[Discussion] Job generation / submission hooks & Atlas integration

[Kostas Kloudas-4]

Hi all,

I do not have a strong opinion on the topic yet, but I would like to
share my thoughts on this.

In the solution proposing a wrapping AtlasExecutor around the Flink
Executors, if we allow the user to use the CLI to submit jobs, then
this means that the CLI code may have to change so that it injects the
executor option to AtlasExecutor (transparently to the user), and then
the AtlasExecutor should take what the user has actually set as
pipeline executor and find the adequate executor. If this is not done
transparently, then the user should do sth explicit to point Flink to
Atlas and then to the correct executor, which implies that we should
add user-facing stuff (like cli options) to Flink.

For the solution of adding getPipeline() to the JobListener, I think
that from a design perspective, it does not fit in the listener
itself. The listener is a "passive" entity that is expected to listen
to specific "events". Adding a getter does not fit there. Other
options for the getPipeline() method are:
1) add it as a method to the JobClient
2) add it as an argument to the methods of the JobListener (along with
the JobClient and the throwable)

Alternative 1) would currently work because the JobClient is only
instantiated by the executor. But in the future, we may (and probably
will because of implications of FLIP-85) allow a JobClient to get
"attached" to a running job. In this case, the getPipeline() will not
have a pipeline to return.
Alternative 2) will break existing code, which I am not sure how
important this is as the JobListener is a new feature and I guess some
but not many users.

As a sidenote, if I am not mistaken, apart from Yarn, none of the
above solutions would work in per-job mode for Kuberneter, Mesos or
with web-submissions. These modes go through "special" execution
environments that use them simply to extract the JobGraph which then
they submit to the cluster. In this case, there is no executor
involved. Are these cases important to you?

Finally, another solution, although more drastic and more involved,
could be to have a "JobListener" running on the jobMaster. This will
collect the relevant info and send them to Atlas. But I am not sure
how Atlas works and if it requires the data to be extracted on the
client side. I am saying this because the JobMasters may be running
anywhere in a cluster while the clients may run on designated machines
which can have specific configurations, e.g. open ports to communicate
with a specific Atlas server.

Cheers,
Kostas

On Thu, Mar 12, 2020 at 3:19 PM Stephan Ewen <[hidden email]> wrote:

>
> Hi Gyula!
>
> My main motivation was to try and avoid mixing an internal interface
> (Pipeline) with public API. It looks like this is trying to go "public
> stable", but doesn't really do it exactly because of mixing "pipeline" into
> this.
> You would need to cast "Pipeline" and work on internal classes in the
> implementation.
>
> If we use an "internal API" or a "semi-stable SPI" class, it looks at a
> first glance a bit cleaner and more maintainable (opening up less surface)
> to make the PipelineExecutor a "stable SPI".
> I have not checked out all the details, though.
>
> Best,
> Stephan
>
>
> On Thu, Mar 12, 2020 at 2:47 PM Gyula Fóra <[hidden email]> wrote:
>
> > Hi Stephan!
> >
> > Thanks for checking this out. I agree that wrapping the other
> > PipelineExecutors with a delegating AtlasExecutor would be a good
> > alternative approach to implement this but I actually feel that it suffers
> > even more problems than exposing the Pipeline instance in the JobListener.
> >
> > The main idea with the Atlas integration would be to have the Atlas hook
> > logic in the Atlas project where it would be maintained. This means that
> > any approach we take has to rely on public APIs. The JobListener is already
> > a public evolving API while the PipelineExecutor and the factory is purely
> > internal. Even if we make it public it will still expose the Pipeline so we
> > did not gain much on the public/internal API front.
> >
> > I also feel that since the Atlas hook logic should only observe the
> > pipeline and collect information the JobListener interface seems an ideal
> > match and the implementation can be pretty lightweight. From a purely
> > implementation perspective adding an Executor would be more heavy as it has
> > to properly delegate to an other executor making sure that we don't break
> > anything.
> >
> > Don't take me wrong, I am not opposed to reworking the implementations we
> > have as it's very simple at this point but I also want to make sure that we
> > take the approach that is simple from a maintainability standpoint. Of
> > course my argument rests on the assumption that the AtlasHook itself will
> > live outside of the Flink project, thats another question.
> >
> > Cheers,
> > Gyula
> >
> > On Thu, Mar 12, 2020 at 11:34 AM Stephan Ewen <[hidden email]> wrote:
> >
> > > Hi all!
> > >
> > > In general, nice idea to support this integration with Atlas.
> > >
> > > I think we could make this a bit easier/lightweight with a small change.
> > > One of the issues that is not super nice is that this starts exposing the
> > > (currently empty) Pipeline interface in the public API.
> > > The Pipeline is an SPI interface that would be good to hide in the API.
> > >
> > > Since 1.10, Flink has the notion of Executors, which take the pipeline
> > and
> > > execute them. Meaning each pipeline is passed on anyways. And executors
> > are
> > > already configurable in the Flink configuration.
> > > So, instead of passing the pipeline both "down" (to the executor) and "to
> > > the side" (JobListener), could we just have a wrapping "AtlasExecutor"
> > that
> > > takes the pipeline, does whatever it wants, and then passes it to the
> > > proper executor? This would also have the advantage that it supports
> > making
> > > changes to the pipeline, if needed in the future. For example, if there
> > is
> > > ever the need to add additional configuration fields, set properties, add
> > > "labels" or so, this could be easily done in the suggested approach.
> > >
> > > I tried to sketch this in the picture below, pardon my bad drawing.
> > >
> > > [image: Listener_Executor.png]
> > >
> > >
> > >
> > https://xjcrkw.bn.files.1drv.com/y4pWH57aEvLU5Ww4REC9XLi7nJMLGHq2smPSzaslU8ogywFDcMkP-_Rsl8B1njf4qphodim6bgnLTNFwNoEuwFdTuA2Xmf7CJ_8lTJjrKlFlDwrugVeBQzEhAY7n_5j2bumwDBf29jn_tZ1ueZxe2slhLkPC-9K6Dry_vpvRvZRY-CSnQXxj9jDf7P53Vz1K9Ez/Listener_Executor.png?psid=1
> > >
> > >
> > > Best,
> > > Stephan
> > >
> > >
> > > On Wed, Mar 11, 2020 at 11:41 AM Aljoscha Krettek <[hidden email]>
> > > wrote:
> > >
> > >> Thanks! I'm reading the document now and will get back to you.
> > >>
> > >> Best,
> > >> Aljoscha
> > >>
> > >
> >

[Kostas Kloudas-4]

Hi again,

Just to clarify, I am not against exposing the Pipeline if this will
lead to a "clean" solution.
And, I. forgot to say that the last solution, if adopted, would have
to work on the JobGraph, which may not be that desirable.

Kostas

On Thu, Mar 12, 2020 at 8:26 PM Kostas Kloudas <[hidden email]> wrote:

>
> Hi all,
>
> I do not have a strong opinion on the topic yet, but I would like to
> share my thoughts on this.
>
> In the solution proposing a wrapping AtlasExecutor around the Flink
> Executors, if we allow the user to use the CLI to submit jobs, then
> this means that the CLI code may have to change so that it injects the
> executor option to AtlasExecutor (transparently to the user), and then
> the AtlasExecutor should take what the user has actually set as
> pipeline executor and find the adequate executor. If this is not done
> transparently, then the user should do sth explicit to point Flink to
> Atlas and then to the correct executor, which implies that we should
> add user-facing stuff (like cli options) to Flink.
>
> For the solution of adding getPipeline() to the JobListener, I think
> that from a design perspective, it does not fit in the listener
> itself. The listener is a "passive" entity that is expected to listen
> to specific "events". Adding a getter does not fit there. Other
> options for the getPipeline() method are:
> 1) add it as a method to the JobClient
> 2) add it as an argument to the methods of the JobListener (along with
> the JobClient and the throwable)
>
> Alternative 1) would currently work because the JobClient is only
> instantiated by the executor. But in the future, we may (and probably
> will because of implications of FLIP-85) allow a JobClient to get
> "attached" to a running job. In this case, the getPipeline() will not
> have a pipeline to return.
> Alternative 2) will break existing code, which I am not sure how
> important this is as the JobListener is a new feature and I guess some
> but not many users.
>
> As a sidenote, if I am not mistaken, apart from Yarn, none of the
> above solutions would work in per-job mode for Kuberneter, Mesos or
> with web-submissions. These modes go through "special" execution
> environments that use them simply to extract the JobGraph which then
> they submit to the cluster. In this case, there is no executor
> involved. Are these cases important to you?
>
> Finally, another solution, although more drastic and more involved,
> could be to have a "JobListener" running on the jobMaster. This will
> collect the relevant info and send them to Atlas. But I am not sure
> how Atlas works and if it requires the data to be extracted on the
> client side. I am saying this because the JobMasters may be running
> anywhere in a cluster while the clients may run on designated machines
> which can have specific configurations, e.g. open ports to communicate
> with a specific Atlas server.
>
> Cheers,
> Kostas
>
> On Thu, Mar 12, 2020 at 3:19 PM Stephan Ewen <[hidden email]> wrote:
> >
> > Hi Gyula!
> >
> > My main motivation was to try and avoid mixing an internal interface
> > (Pipeline) with public API. It looks like this is trying to go "public
> > stable", but doesn't really do it exactly because of mixing "pipeline" into
> > this.
> > You would need to cast "Pipeline" and work on internal classes in the
> > implementation.
> >
> > If we use an "internal API" or a "semi-stable SPI" class, it looks at a
> > first glance a bit cleaner and more maintainable (opening up less surface)
> > to make the PipelineExecutor a "stable SPI".
> > I have not checked out all the details, though.
> >
> > Best,
> > Stephan
> >
> >
> > On Thu, Mar 12, 2020 at 2:47 PM Gyula Fóra <[hidden email]> wrote:
> >
> > > Hi Stephan!
> > >
> > > Thanks for checking this out. I agree that wrapping the other
> > > PipelineExecutors with a delegating AtlasExecutor would be a good
> > > alternative approach to implement this but I actually feel that it suffers
> > > even more problems than exposing the Pipeline instance in the JobListener.
> > >
> > > The main idea with the Atlas integration would be to have the Atlas hook
> > > logic in the Atlas project where it would be maintained. This means that
> > > any approach we take has to rely on public APIs. The JobListener is already
> > > a public evolving API while the PipelineExecutor and the factory is purely
> > > internal. Even if we make it public it will still expose the Pipeline so we
> > > did not gain much on the public/internal API front.
> > >
> > > I also feel that since the Atlas hook logic should only observe the
> > > pipeline and collect information the JobListener interface seems an ideal
> > > match and the implementation can be pretty lightweight. From a purely
> > > implementation perspective adding an Executor would be more heavy as it has
> > > to properly delegate to an other executor making sure that we don't break
> > > anything.
> > >
> > > Don't take me wrong, I am not opposed to reworking the implementations we
> > > have as it's very simple at this point but I also want to make sure that we
> > > take the approach that is simple from a maintainability standpoint. Of
> > > course my argument rests on the assumption that the AtlasHook itself will
> > > live outside of the Flink project, thats another question.
> > >
> > > Cheers,
> > > Gyula
> > >
> > > On Thu, Mar 12, 2020 at 11:34 AM Stephan Ewen <[hidden email]> wrote:
> > >
> > > > Hi all!
> > > >
> > > > In general, nice idea to support this integration with Atlas.
> > > >
> > > > I think we could make this a bit easier/lightweight with a small change.
> > > > One of the issues that is not super nice is that this starts exposing the
> > > > (currently empty) Pipeline interface in the public API.
> > > > The Pipeline is an SPI interface that would be good to hide in the API.
> > > >
> > > > Since 1.10, Flink has the notion of Executors, which take the pipeline
> > > and
> > > > execute them. Meaning each pipeline is passed on anyways. And executors
> > > are
> > > > already configurable in the Flink configuration.
> > > > So, instead of passing the pipeline both "down" (to the executor) and "to
> > > > the side" (JobListener), could we just have a wrapping "AtlasExecutor"
> > > that
> > > > takes the pipeline, does whatever it wants, and then passes it to the
> > > > proper executor? This would also have the advantage that it supports
> > > making
> > > > changes to the pipeline, if needed in the future. For example, if there
> > > is
> > > > ever the need to add additional configuration fields, set properties, add
> > > > "labels" or so, this could be easily done in the suggested approach.
> > > >
> > > > I tried to sketch this in the picture below, pardon my bad drawing.
> > > >
> > > > [image: Listener_Executor.png]
> > > >
> > > >
> > > >
> > > https://xjcrkw.bn.files.1drv.com/y4pWH57aEvLU5Ww4REC9XLi7nJMLGHq2smPSzaslU8ogywFDcMkP-_Rsl8B1njf4qphodim6bgnLTNFwNoEuwFdTuA2Xmf7CJ_8lTJjrKlFlDwrugVeBQzEhAY7n_5j2bumwDBf29jn_tZ1ueZxe2slhLkPC-9K6Dry_vpvRvZRY-CSnQXxj9jDf7P53Vz1K9Ez/Listener_Executor.png?psid=1
> > > >
> > > >
> > > > Best,
> > > > Stephan
> > > >
> > > >
> > > > On Wed, Mar 11, 2020 at 11:41 AM Aljoscha Krettek <[hidden email]>
> > > > wrote:
> > > >
> > > >> Thanks! I'm reading the document now and will get back to you.
> > > >>
> > > >> Best,
> > > >> Aljoscha
> > > >>
> > > >
> > >

[Gyula Fóra]

Thanks Kostas, I have to review the possible limitations with the Executor
before I can properly answer.

Regarding you comments for the listener pattern, we proposed in the
document to include the getPipeline() in the JobClient itself as you
suggested to fit the pattern :) For not always being able to return the
pipeline, this might be expected depending on how the JobClient, so we need
to handle it some way.


On Thu, Mar 12, 2020 at 8:30 PM Kostas Kloudas <[hidden email]> wrote:

> Hi again,
>
> Just to clarify, I am not against exposing the Pipeline if this will
> lead to a "clean" solution.
> And, I. forgot to say that the last solution, if adopted, would have
> to work on the JobGraph, which may not be that desirable.
>
> Kostas
>
> On Thu, Mar 12, 2020 at 8:26 PM Kostas Kloudas <[hidden email]> wrote:
> >
> > Hi all,
> >
> > I do not have a strong opinion on the topic yet, but I would like to
> > share my thoughts on this.
> >
> > In the solution proposing a wrapping AtlasExecutor around the Flink
> > Executors, if we allow the user to use the CLI to submit jobs, then
> > this means that the CLI code may have to change so that it injects the
> > executor option to AtlasExecutor (transparently to the user), and then
> > the AtlasExecutor should take what the user has actually set as
> > pipeline executor and find the adequate executor. If this is not done
> > transparently, then the user should do sth explicit to point Flink to
> > Atlas and then to the correct executor, which implies that we should
> > add user-facing stuff (like cli options) to Flink.
> >
> > For the solution of adding getPipeline() to the JobListener, I think
> > that from a design perspective, it does not fit in the listener
> > itself. The listener is a "passive" entity that is expected to listen
> > to specific "events". Adding a getter does not fit there. Other
> > options for the getPipeline() method are:
> > 1) add it as a method to the JobClient
> > 2) add it as an argument to the methods of the JobListener (along with
> > the JobClient and the throwable)
> >
> > Alternative 1) would currently work because the JobClient is only
> > instantiated by the executor. But in the future, we may (and probably
> > will because of implications of FLIP-85) allow a JobClient to get
> > "attached" to a running job. In this case, the getPipeline() will not
> > have a pipeline to return.
> > Alternative 2) will break existing code, which I am not sure how
> > important this is as the JobListener is a new feature and I guess some
> > but not many users.
> >
> > As a sidenote, if I am not mistaken, apart from Yarn, none of the
> > above solutions would work in per-job mode for Kuberneter, Mesos or
> > with web-submissions. These modes go through "special" execution
> > environments that use them simply to extract the JobGraph which then
> > they submit to the cluster. In this case, there is no executor
> > involved. Are these cases important to you?
> >
> > Finally, another solution, although more drastic and more involved,
> > could be to have a "JobListener" running on the jobMaster. This will
> > collect the relevant info and send them to Atlas. But I am not sure
> > how Atlas works and if it requires the data to be extracted on the
> > client side. I am saying this because the JobMasters may be running
> > anywhere in a cluster while the clients may run on designated machines
> > which can have specific configurations, e.g. open ports to communicate
> > with a specific Atlas server.
> >
> > Cheers,
> > Kostas
> >
> > On Thu, Mar 12, 2020 at 3:19 PM Stephan Ewen <[hidden email]> wrote:
> > >
> > > Hi Gyula!
> > >
> > > My main motivation was to try and avoid mixing an internal interface
> > > (Pipeline) with public API. It looks like this is trying to go "public
> > > stable", but doesn't really do it exactly because of mixing "pipeline"
> into
> > > this.
> > > You would need to cast "Pipeline" and work on internal classes in the
> > > implementation.
> > >
> > > If we use an "internal API" or a "semi-stable SPI" class, it looks at a
> > > first glance a bit cleaner and more maintainable (opening up less
> surface)
> > > to make the PipelineExecutor a "stable SPI".
> > > I have not checked out all the details, though.
> > >
> > > Best,
> > > Stephan
> > >
> > >
> > > On Thu, Mar 12, 2020 at 2:47 PM Gyula Fóra <[hidden email]>
> wrote:
> > >
> > > > Hi Stephan!
> > > >
> > > > Thanks for checking this out. I agree that wrapping the other
> > > > PipelineExecutors with a delegating AtlasExecutor would be a good
> > > > alternative approach to implement this but I actually feel that it
> suffers
> > > > even more problems than exposing the Pipeline instance in the
> JobListener.
> > > >
> > > > The main idea with the Atlas integration would be to have the Atlas
> hook
> > > > logic in the Atlas project where it would be maintained. This means
> that
> > > > any approach we take has to rely on public APIs. The JobListener is
> already
> > > > a public evolving API while the PipelineExecutor and the factory is
> purely
> > > > internal. Even if we make it public it will still expose the
> Pipeline so we
> > > > did not gain much on the public/internal API front.
> > > >
> > > > I also feel that since the Atlas hook logic should only observe the
> > > > pipeline and collect information the JobListener interface seems an
> ideal
> > > > match and the implementation can be pretty lightweight. From a purely
> > > > implementation perspective adding an Executor would be more heavy as
> it has
> > > > to properly delegate to an other executor making sure that we don't
> break
> > > > anything.
> > > >
> > > > Don't take me wrong, I am not opposed to reworking the
> implementations we
> > > > have as it's very simple at this point but I also want to make sure
> that we
> > > > take the approach that is simple from a maintainability standpoint.
> Of
> > > > course my argument rests on the assumption that the AtlasHook itself
> will
> > > > live outside of the Flink project, thats another question.
> > > >
> > > > Cheers,
> > > > Gyula
> > > >
> > > > On Thu, Mar 12, 2020 at 11:34 AM Stephan Ewen <[hidden email]>
> wrote:
> > > >
> > > > > Hi all!
> > > > >
> > > > > In general, nice idea to support this integration with Atlas.
> > > > >
> > > > > I think we could make this a bit easier/lightweight with a small
> change.
> > > > > One of the issues that is not super nice is that this starts
> exposing the
> > > > > (currently empty) Pipeline interface in the public API.
> > > > > The Pipeline is an SPI interface that would be good to hide in the
> API.
> > > > >
> > > > > Since 1.10, Flink has the notion of Executors, which take the
> pipeline
> > > > and
> > > > > execute them. Meaning each pipeline is passed on anyways. And
> executors
> > > > are
> > > > > already configurable in the Flink configuration.
> > > > > So, instead of passing the pipeline both "down" (to the executor)
> and "to
> > > > > the side" (JobListener), could we just have a wrapping
> "AtlasExecutor"
> > > > that
> > > > > takes the pipeline, does whatever it wants, and then passes it to
> the
> > > > > proper executor? This would also have the advantage that it
> supports
> > > > making
> > > > > changes to the pipeline, if needed in the future. For example, if
> there
> > > > is
> > > > > ever the need to add additional configuration fields, set
> properties, add
> > > > > "labels" or so, this could be easily done in the suggested
> approach.
> > > > >
> > > > > I tried to sketch this in the picture below, pardon my bad drawing.
> > > > >
> > > > > [image: Listener_Executor.png]
> > > > >
> > > > >
> > > > >
> > > >
> https://xjcrkw.bn.files.1drv.com/y4pWH57aEvLU5Ww4REC9XLi7nJMLGHq2smPSzaslU8ogywFDcMkP-_Rsl8B1njf4qphodim6bgnLTNFwNoEuwFdTuA2Xmf7CJ_8lTJjrKlFlDwrugVeBQzEhAY7n_5j2bumwDBf29jn_tZ1ueZxe2slhLkPC-9K6Dry_vpvRvZRY-CSnQXxj9jDf7P53Vz1K9Ez/Listener_Executor.png?psid=1
> > > > >
> > > > >
> > > > > Best,
> > > > > Stephan
> > > > >
> > > > >
> > > > > On Wed, Mar 11, 2020 at 11:41 AM Aljoscha Krettek <
> [hidden email]>
> > > > > wrote:
> > > > >
> > > > >> Thanks! I'm reading the document now and will get back to you.
> > > > >>
> > > > >> Best,
> > > > >> Aljoscha
> > > > >>
> > > > >
> > > >
>

[Kostas Kloudas-4]

Thanks Gyula,

Looking forward to your comments.
Just to let you know, I would not like having a method that in some
cases works as expected and in some other ones it does not. It would
be nice if we could expose consistent behaviour to the users.

On Thu, Mar 12, 2020 at 8:44 PM Gyula Fóra <[hidden email]> wrote:

>
> Thanks Kostas, I have to review the possible limitations with the Executor
> before I can properly answer.
>
> Regarding you comments for the listener pattern, we proposed in the
> document to include the getPipeline() in the JobClient itself as you
> suggested to fit the pattern :) For not always being able to return the
> pipeline, this might be expected depending on how the JobClient, so we need
> to handle it some way.
>
>
> On Thu, Mar 12, 2020 at 8:30 PM Kostas Kloudas <[hidden email]> wrote:
>
> > Hi again,
> >
> > Just to clarify, I am not against exposing the Pipeline if this will
> > lead to a "clean" solution.
> > And, I. forgot to say that the last solution, if adopted, would have
> > to work on the JobGraph, which may not be that desirable.
> >
> > Kostas
> >
> > On Thu, Mar 12, 2020 at 8:26 PM Kostas Kloudas <[hidden email]> wrote:
> > >
> > > Hi all,
> > >
> > > I do not have a strong opinion on the topic yet, but I would like to
> > > share my thoughts on this.
> > >
> > > In the solution proposing a wrapping AtlasExecutor around the Flink
> > > Executors, if we allow the user to use the CLI to submit jobs, then
> > > this means that the CLI code may have to change so that it injects the
> > > executor option to AtlasExecutor (transparently to the user), and then
> > > the AtlasExecutor should take what the user has actually set as
> > > pipeline executor and find the adequate executor. If this is not done
> > > transparently, then the user should do sth explicit to point Flink to
> > > Atlas and then to the correct executor, which implies that we should
> > > add user-facing stuff (like cli options) to Flink.
> > >
> > > For the solution of adding getPipeline() to the JobListener, I think
> > > that from a design perspective, it does not fit in the listener
> > > itself. The listener is a "passive" entity that is expected to listen
> > > to specific "events". Adding a getter does not fit there. Other
> > > options for the getPipeline() method are:
> > > 1) add it as a method to the JobClient
> > > 2) add it as an argument to the methods of the JobListener (along with
> > > the JobClient and the throwable)
> > >
> > > Alternative 1) would currently work because the JobClient is only
> > > instantiated by the executor. But in the future, we may (and probably
> > > will because of implications of FLIP-85) allow a JobClient to get
> > > "attached" to a running job. In this case, the getPipeline() will not
> > > have a pipeline to return.
> > > Alternative 2) will break existing code, which I am not sure how
> > > important this is as the JobListener is a new feature and I guess some
> > > but not many users.
> > >
> > > As a sidenote, if I am not mistaken, apart from Yarn, none of the
> > > above solutions would work in per-job mode for Kuberneter, Mesos or
> > > with web-submissions. These modes go through "special" execution
> > > environments that use them simply to extract the JobGraph which then
> > > they submit to the cluster. In this case, there is no executor
> > > involved. Are these cases important to you?
> > >
> > > Finally, another solution, although more drastic and more involved,
> > > could be to have a "JobListener" running on the jobMaster. This will
> > > collect the relevant info and send them to Atlas. But I am not sure
> > > how Atlas works and if it requires the data to be extracted on the
> > > client side. I am saying this because the JobMasters may be running
> > > anywhere in a cluster while the clients may run on designated machines
> > > which can have specific configurations, e.g. open ports to communicate
> > > with a specific Atlas server.
> > >
> > > Cheers,
> > > Kostas
> > >
> > > On Thu, Mar 12, 2020 at 3:19 PM Stephan Ewen <[hidden email]> wrote:
> > > >
> > > > Hi Gyula!
> > > >
> > > > My main motivation was to try and avoid mixing an internal interface
> > > > (Pipeline) with public API. It looks like this is trying to go "public
> > > > stable", but doesn't really do it exactly because of mixing "pipeline"
> > into
> > > > this.
> > > > You would need to cast "Pipeline" and work on internal classes in the
> > > > implementation.
> > > >
> > > > If we use an "internal API" or a "semi-stable SPI" class, it looks at a
> > > > first glance a bit cleaner and more maintainable (opening up less
> > surface)
> > > > to make the PipelineExecutor a "stable SPI".
> > > > I have not checked out all the details, though.
> > > >
> > > > Best,
> > > > Stephan
> > > >
> > > >
> > > > On Thu, Mar 12, 2020 at 2:47 PM Gyula Fóra <[hidden email]>
> > wrote:
> > > >
> > > > > Hi Stephan!
> > > > >
> > > > > Thanks for checking this out. I agree that wrapping the other
> > > > > PipelineExecutors with a delegating AtlasExecutor would be a good
> > > > > alternative approach to implement this but I actually feel that it
> > suffers
> > > > > even more problems than exposing the Pipeline instance in the
> > JobListener.
> > > > >
> > > > > The main idea with the Atlas integration would be to have the Atlas
> > hook
> > > > > logic in the Atlas project where it would be maintained. This means
> > that
> > > > > any approach we take has to rely on public APIs. The JobListener is
> > already
> > > > > a public evolving API while the PipelineExecutor and the factory is
> > purely
> > > > > internal. Even if we make it public it will still expose the
> > Pipeline so we
> > > > > did not gain much on the public/internal API front.
> > > > >
> > > > > I also feel that since the Atlas hook logic should only observe the
> > > > > pipeline and collect information the JobListener interface seems an
> > ideal
> > > > > match and the implementation can be pretty lightweight. From a purely
> > > > > implementation perspective adding an Executor would be more heavy as
> > it has
> > > > > to properly delegate to an other executor making sure that we don't
> > break
> > > > > anything.
> > > > >
> > > > > Don't take me wrong, I am not opposed to reworking the
> > implementations we
> > > > > have as it's very simple at this point but I also want to make sure
> > that we
> > > > > take the approach that is simple from a maintainability standpoint.
> > Of
> > > > > course my argument rests on the assumption that the AtlasHook itself
> > will
> > > > > live outside of the Flink project, thats another question.
> > > > >
> > > > > Cheers,
> > > > > Gyula
> > > > >
> > > > > On Thu, Mar 12, 2020 at 11:34 AM Stephan Ewen <[hidden email]>
> > wrote:
> > > > >
> > > > > > Hi all!
> > > > > >
> > > > > > In general, nice idea to support this integration with Atlas.
> > > > > >
> > > > > > I think we could make this a bit easier/lightweight with a small
> > change.
> > > > > > One of the issues that is not super nice is that this starts
> > exposing the
> > > > > > (currently empty) Pipeline interface in the public API.
> > > > > > The Pipeline is an SPI interface that would be good to hide in the
> > API.
> > > > > >
> > > > > > Since 1.10, Flink has the notion of Executors, which take the
> > pipeline
> > > > > and
> > > > > > execute them. Meaning each pipeline is passed on anyways. And
> > executors
> > > > > are
> > > > > > already configurable in the Flink configuration.
> > > > > > So, instead of passing the pipeline both "down" (to the executor)
> > and "to
> > > > > > the side" (JobListener), could we just have a wrapping
> > "AtlasExecutor"
> > > > > that
> > > > > > takes the pipeline, does whatever it wants, and then passes it to
> > the
> > > > > > proper executor? This would also have the advantage that it
> > supports
> > > > > making
> > > > > > changes to the pipeline, if needed in the future. For example, if
> > there
> > > > > is
> > > > > > ever the need to add additional configuration fields, set
> > properties, add
> > > > > > "labels" or so, this could be easily done in the suggested
> > approach.
> > > > > >
> > > > > > I tried to sketch this in the picture below, pardon my bad drawing.
> > > > > >
> > > > > > [image: Listener_Executor.png]
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > https://xjcrkw.bn.files.1drv.com/y4pWH57aEvLU5Ww4REC9XLi7nJMLGHq2smPSzaslU8ogywFDcMkP-_Rsl8B1njf4qphodim6bgnLTNFwNoEuwFdTuA2Xmf7CJ_8lTJjrKlFlDwrugVeBQzEhAY7n_5j2bumwDBf29jn_tZ1ueZxe2slhLkPC-9K6Dry_vpvRvZRY-CSnQXxj9jDf7P53Vz1K9Ez/Listener_Executor.png?psid=1
> > > > > >
> > > > > >
> > > > > > Best,
> > > > > > Stephan
> > > > > >
> > > > > >
> > > > > > On Wed, Mar 11, 2020 at 11:41 AM Aljoscha Krettek <
> > [hidden email]>
> > > > > > wrote:
> > > > > >
> > > > > >> Thanks! I'm reading the document now and will get back to you.
> > > > > >>
> > > > > >> Best,
> > > > > >> Aljoscha
> > > > > >>
> > > > > >
> > > > >
> >

[Gyula Fóra]

Thanks again Kostas for diving deep into this, it is great feedback!

I agree with the concerns regarding the custom executor, it has to be able
to properly handle the "original" executor somehow.
This might be quite tricky if we want to implement the AtlasExecutor
outside Flink. In any case does not really feel clean or lightweight at
first glance.

As for the JobClient/JobListener/Pipeline question, as you brought up the
possibility for later attaching the JobClient, maybe the best route for
this would be to
add the Pipeline as a method parameter in the JobListener. It would break
code compatibility but at least would have a consistent behavior.

Now to the big problem of not having executors / joblisteners work in
kuberentes-per-job,  web, etc modes. I was not aware of this problem until
now, this also seems to affect the whole concept of the JobListener
interface. What good is a JobListener if it only listens to certain kind of
deployments :)

Incidentally, in my first proposal (and prototype) I had the atlashook
running on the JobMaster with an extra addition to a JobGraphGenerator hook
that could be registered in the StreamExecutionEnvironment. This meant that
we could work on the StreamGraph, register metadata in the JobGraph, and
execute the actual atlas registration logic in the JobMaster when the job
starts.

Looking back this is a much more complex, and uglier, logic than having a
simple JobListener. But it would at least work in all possible job
submission scenarios, as long as the JobGraph was generated through the
StreamGraph logic (which should be always).

Cheers,
Gyula


On Thu, Mar 12, 2020 at 8:53 PM Kostas Kloudas <[hidden email]> wrote:

> Thanks Gyula,
>
> Looking forward to your comments.
> Just to let you know, I would not like having a method that in some
> cases works as expected and in some other ones it does not. It would
> be nice if we could expose consistent behaviour to the users.
>
> On Thu, Mar 12, 2020 at 8:44 PM Gyula Fóra <[hidden email]> wrote:
> >
> > Thanks Kostas, I have to review the possible limitations with the
> Executor
> > before I can properly answer.
> >
> > Regarding you comments for the listener pattern, we proposed in the
> > document to include the getPipeline() in the JobClient itself as you
> > suggested to fit the pattern :) For not always being able to return the
> > pipeline, this might be expected depending on how the JobClient, so we
> need
> > to handle it some way.
> >
> >
> > On Thu, Mar 12, 2020 at 8:30 PM Kostas Kloudas <[hidden email]>
> wrote:
> >
> > > Hi again,
> > >
> > > Just to clarify, I am not against exposing the Pipeline if this will
> > > lead to a "clean" solution.
> > > And, I. forgot to say that the last solution, if adopted, would have
> > > to work on the JobGraph, which may not be that desirable.
> > >
> > > Kostas
> > >
> > > On Thu, Mar 12, 2020 at 8:26 PM Kostas Kloudas <[hidden email]>
> wrote:
> > > >
> > > > Hi all,
> > > >
> > > > I do not have a strong opinion on the topic yet, but I would like to
> > > > share my thoughts on this.
> > > >
> > > > In the solution proposing a wrapping AtlasExecutor around the Flink
> > > > Executors, if we allow the user to use the CLI to submit jobs, then
> > > > this means that the CLI code may have to change so that it injects
> the
> > > > executor option to AtlasExecutor (transparently to the user), and
> then
> > > > the AtlasExecutor should take what the user has actually set as
> > > > pipeline executor and find the adequate executor. If this is not done
> > > > transparently, then the user should do sth explicit to point Flink to
> > > > Atlas and then to the correct executor, which implies that we should
> > > > add user-facing stuff (like cli options) to Flink.
> > > >
> > > > For the solution of adding getPipeline() to the JobListener, I think
> > > > that from a design perspective, it does not fit in the listener
> > > > itself. The listener is a "passive" entity that is expected to listen
> > > > to specific "events". Adding a getter does not fit there. Other
> > > > options for the getPipeline() method are:
> > > > 1) add it as a method to the JobClient
> > > > 2) add it as an argument to the methods of the JobListener (along
> with
> > > > the JobClient and the throwable)
> > > >
> > > > Alternative 1) would currently work because the JobClient is only
> > > > instantiated by the executor. But in the future, we may (and probably
> > > > will because of implications of FLIP-85) allow a JobClient to get
> > > > "attached" to a running job. In this case, the getPipeline() will not
> > > > have a pipeline to return.
> > > > Alternative 2) will break existing code, which I am not sure how
> > > > important this is as the JobListener is a new feature and I guess
> some
> > > > but not many users.
> > > >
> > > > As a sidenote, if I am not mistaken, apart from Yarn, none of the
> > > > above solutions would work in per-job mode for Kuberneter, Mesos or
> > > > with web-submissions. These modes go through "special" execution
> > > > environments that use them simply to extract the JobGraph which then
> > > > they submit to the cluster. In this case, there is no executor
> > > > involved. Are these cases important to you?
> > > >
> > > > Finally, another solution, although more drastic and more involved,
> > > > could be to have a "JobListener" running on the jobMaster. This will
> > > > collect the relevant info and send them to Atlas. But I am not sure
> > > > how Atlas works and if it requires the data to be extracted on the
> > > > client side. I am saying this because the JobMasters may be running
> > > > anywhere in a cluster while the clients may run on designated
> machines
> > > > which can have specific configurations, e.g. open ports to
> communicate
> > > > with a specific Atlas server.
> > > >
> > > > Cheers,
> > > > Kostas
> > > >
> > > > On Thu, Mar 12, 2020 at 3:19 PM Stephan Ewen <[hidden email]>
> wrote:
> > > > >
> > > > > Hi Gyula!
> > > > >
> > > > > My main motivation was to try and avoid mixing an internal
> interface
> > > > > (Pipeline) with public API. It looks like this is trying to go
> "public
> > > > > stable", but doesn't really do it exactly because of mixing
> "pipeline"
> > > into
> > > > > this.
> > > > > You would need to cast "Pipeline" and work on internal classes in
> the
> > > > > implementation.
> > > > >
> > > > > If we use an "internal API" or a "semi-stable SPI" class, it looks
> at a
> > > > > first glance a bit cleaner and more maintainable (opening up less
> > > surface)
> > > > > to make the PipelineExecutor a "stable SPI".
> > > > > I have not checked out all the details, though.
> > > > >
> > > > > Best,
> > > > > Stephan
> > > > >
> > > > >
> > > > > On Thu, Mar 12, 2020 at 2:47 PM Gyula Fóra <[hidden email]>
> > > wrote:
> > > > >
> > > > > > Hi Stephan!
> > > > > >
> > > > > > Thanks for checking this out. I agree that wrapping the other
> > > > > > PipelineExecutors with a delegating AtlasExecutor would be a good
> > > > > > alternative approach to implement this but I actually feel that
> it
> > > suffers
> > > > > > even more problems than exposing the Pipeline instance in the
> > > JobListener.
> > > > > >
> > > > > > The main idea with the Atlas integration would be to have the
> Atlas
> > > hook
> > > > > > logic in the Atlas project where it would be maintained. This
> means
> > > that
> > > > > > any approach we take has to rely on public APIs. The JobListener
> is
> > > already
> > > > > > a public evolving API while the PipelineExecutor and the factory
> is
> > > purely
> > > > > > internal. Even if we make it public it will still expose the
> > > Pipeline so we
> > > > > > did not gain much on the public/internal API front.
> > > > > >
> > > > > > I also feel that since the Atlas hook logic should only observe
> the
> > > > > > pipeline and collect information the JobListener interface seems
> an
> > > ideal
> > > > > > match and the implementation can be pretty lightweight. From a
> purely
> > > > > > implementation perspective adding an Executor would be more
> heavy as
> > > it has
> > > > > > to properly delegate to an other executor making sure that we
> don't
> > > break
> > > > > > anything.
> > > > > >
> > > > > > Don't take me wrong, I am not opposed to reworking the
> > > implementations we
> > > > > > have as it's very simple at this point but I also want to make
> sure
> > > that we
> > > > > > take the approach that is simple from a maintainability
> standpoint.
> > > Of
> > > > > > course my argument rests on the assumption that the AtlasHook
> itself
> > > will
> > > > > > live outside of the Flink project, thats another question.
> > > > > >
> > > > > > Cheers,
> > > > > > Gyula
> > > > > >
> > > > > > On Thu, Mar 12, 2020 at 11:34 AM Stephan Ewen <[hidden email]>
> > > wrote:
> > > > > >
> > > > > > > Hi all!
> > > > > > >
> > > > > > > In general, nice idea to support this integration with Atlas.
> > > > > > >
> > > > > > > I think we could make this a bit easier/lightweight with a
> small
> > > change.
> > > > > > > One of the issues that is not super nice is that this starts
> > > exposing the
> > > > > > > (currently empty) Pipeline interface in the public API.
> > > > > > > The Pipeline is an SPI interface that would be good to hide in
> the
> > > API.
> > > > > > >
> > > > > > > Since 1.10, Flink has the notion of Executors, which take the
> > > pipeline
> > > > > > and
> > > > > > > execute them. Meaning each pipeline is passed on anyways. And
> > > executors
> > > > > > are
> > > > > > > already configurable in the Flink configuration.
> > > > > > > So, instead of passing the pipeline both "down" (to the
> executor)
> > > and "to
> > > > > > > the side" (JobListener), could we just have a wrapping
> > > "AtlasExecutor"
> > > > > > that
> > > > > > > takes the pipeline, does whatever it wants, and then passes it
> to
> > > the
> > > > > > > proper executor? This would also have the advantage that it
> > > supports
> > > > > > making
> > > > > > > changes to the pipeline, if needed in the future. For example,
> if
> > > there
> > > > > > is
> > > > > > > ever the need to add additional configuration fields, set
> > > properties, add
> > > > > > > "labels" or so, this could be easily done in the suggested
> > > approach.
> > > > > > >
> > > > > > > I tried to sketch this in the picture below, pardon my bad
> drawing.
> > > > > > >
> > > > > > > [image: Listener_Executor.png]
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > >
> https://xjcrkw.bn.files.1drv.com/y4pWH57aEvLU5Ww4REC9XLi7nJMLGHq2smPSzaslU8ogywFDcMkP-_Rsl8B1njf4qphodim6bgnLTNFwNoEuwFdTuA2Xmf7CJ_8lTJjrKlFlDwrugVeBQzEhAY7n_5j2bumwDBf29jn_tZ1ueZxe2slhLkPC-9K6Dry_vpvRvZRY-CSnQXxj9jDf7P53Vz1K9Ez/Listener_Executor.png?psid=1
> > > > > > >
> > > > > > >
> > > > > > > Best,
> > > > > > > Stephan
> > > > > > >
> > > > > > >
> > > > > > > On Wed, Mar 11, 2020 at 11:41 AM Aljoscha Krettek <
> > > [hidden email]>
> > > > > > > wrote:
> > > > > > >
> > > > > > >> Thanks! I'm reading the document now and will get back to you.
> > > > > > >>
> > > > > > >> Best,
> > > > > > >> Aljoscha
> > > > > > >>
> > > > > > >
> > > > > >
> > >
>

[tison]

Hi Gyula and all,

Thanks for the discussion so far.

It seems that the requirement is to deliver some metadata of the submitted
job,
and such metadata can be simply extracted from StreamGraph.

I'm unfamiliar with metadata Atlas needs so I make some assumptions.

Assumption:
Metadata needed by Atlas is actually some Flink scope information, such as
input/
output of a node. And this metadata is compile time information so that we
know it
during compiling the StreamGraph.

If the assumption stands, I'm curious whether or not it is an option we
standardize
the JSON representation of StreamGraph which will contain metadata
required. And
pass the JSON representation from generation phase to JobGraph and then
ExecutionGraph and finally retrievable from RestServer(so that we can extend
JobClient to retrieve the plan by querying the cluster instead of have a
pre-configured
one).

It is like `jsonPlan` in ExecutionGraph now(which is exposed by JobPlan REST
endpoint). And I believe rather than JobGraph dump which is a physical plan,
exposing access to StreamGraph dump which is a logical plan is possibly more
interested from user perspective.

Best,
tison.


Gyula Fóra <[hidden email]> 于2020年3月13日周五 下午3:20写道：

> Thanks again Kostas for diving deep into this, it is great feedback!
>
> I agree with the concerns regarding the custom executor, it has to be able
> to properly handle the "original" executor somehow.
> This might be quite tricky if we want to implement the AtlasExecutor
> outside Flink. In any case does not really feel clean or lightweight at
> first glance.
>
> As for the JobClient/JobListener/Pipeline question, as you brought up the
> possibility for later attaching the JobClient, maybe the best route for
> this would be to
> add the Pipeline as a method parameter in the JobListener. It would break
> code compatibility but at least would have a consistent behavior.
>
> Now to the big problem of not having executors / joblisteners work in
> kuberentes-per-job,  web, etc modes. I was not aware of this problem until
> now, this also seems to affect the whole concept of the JobListener
> interface. What good is a JobListener if it only listens to certain kind of
> deployments :)
>
> Incidentally, in my first proposal (and prototype) I had the atlashook
> running on the JobMaster with an extra addition to a JobGraphGenerator hook
> that could be registered in the StreamExecutionEnvironment. This meant that
> we could work on the StreamGraph, register metadata in the JobGraph, and
> execute the actual atlas registration logic in the JobMaster when the job
> starts.
>
> Looking back this is a much more complex, and uglier, logic than having a
> simple JobListener. But it would at least work in all possible job
> submission scenarios, as long as the JobGraph was generated through the
> StreamGraph logic (which should be always).
>
> Cheers,
> Gyula
>
>
> On Thu, Mar 12, 2020 at 8:53 PM Kostas Kloudas <[hidden email]> wrote:
>
> > Thanks Gyula,
> >
> > Looking forward to your comments.
> > Just to let you know, I would not like having a method that in some
> > cases works as expected and in some other ones it does not. It would
> > be nice if we could expose consistent behaviour to the users.
> >
> > On Thu, Mar 12, 2020 at 8:44 PM Gyula Fóra <[hidden email]> wrote:
> > >
> > > Thanks Kostas, I have to review the possible limitations with the
> > Executor
> > > before I can properly answer.
> > >
> > > Regarding you comments for the listener pattern, we proposed in the
> > > document to include the getPipeline() in the JobClient itself as you
> > > suggested to fit the pattern :) For not always being able to return the
> > > pipeline, this might be expected depending on how the JobClient, so we
> > need
> > > to handle it some way.
> > >
> > >
> > > On Thu, Mar 12, 2020 at 8:30 PM Kostas Kloudas <[hidden email]>
> > wrote:
> > >
> > > > Hi again,
> > > >
> > > > Just to clarify, I am not against exposing the Pipeline if this will
> > > > lead to a "clean" solution.
> > > > And, I. forgot to say that the last solution, if adopted, would have
> > > > to work on the JobGraph, which may not be that desirable.
> > > >
> > > > Kostas
> > > >
> > > > On Thu, Mar 12, 2020 at 8:26 PM Kostas Kloudas <[hidden email]>
> > wrote:
> > > > >
> > > > > Hi all,
> > > > >
> > > > > I do not have a strong opinion on the topic yet, but I would like
> to
> > > > > share my thoughts on this.
> > > > >
> > > > > In the solution proposing a wrapping AtlasExecutor around the Flink
> > > > > Executors, if we allow the user to use the CLI to submit jobs, then
> > > > > this means that the CLI code may have to change so that it injects
> > the
> > > > > executor option to AtlasExecutor (transparently to the user), and
> > then
> > > > > the AtlasExecutor should take what the user has actually set as
> > > > > pipeline executor and find the adequate executor. If this is not
> done
> > > > > transparently, then the user should do sth explicit to point Flink
> to
> > > > > Atlas and then to the correct executor, which implies that we
> should
> > > > > add user-facing stuff (like cli options) to Flink.
> > > > >
> > > > > For the solution of adding getPipeline() to the JobListener, I
> think
> > > > > that from a design perspective, it does not fit in the listener
> > > > > itself. The listener is a "passive" entity that is expected to
> listen
> > > > > to specific "events". Adding a getter does not fit there. Other
> > > > > options for the getPipeline() method are:
> > > > > 1) add it as a method to the JobClient
> > > > > 2) add it as an argument to the methods of the JobListener (along
> > with
> > > > > the JobClient and the throwable)
> > > > >
> > > > > Alternative 1) would currently work because the JobClient is only
> > > > > instantiated by the executor. But in the future, we may (and
> probably
> > > > > will because of implications of FLIP-85) allow a JobClient to get
> > > > > "attached" to a running job. In this case, the getPipeline() will
> not
> > > > > have a pipeline to return.
> > > > > Alternative 2) will break existing code, which I am not sure how
> > > > > important this is as the JobListener is a new feature and I guess
> > some
> > > > > but not many users.
> > > > >
> > > > > As a sidenote, if I am not mistaken, apart from Yarn, none of the
> > > > > above solutions would work in per-job mode for Kuberneter, Mesos or
> > > > > with web-submissions. These modes go through "special" execution
> > > > > environments that use them simply to extract the JobGraph which
> then
> > > > > they submit to the cluster. In this case, there is no executor
> > > > > involved. Are these cases important to you?
> > > > >
> > > > > Finally, another solution, although more drastic and more involved,
> > > > > could be to have a "JobListener" running on the jobMaster. This
> will
> > > > > collect the relevant info and send them to Atlas. But I am not sure
> > > > > how Atlas works and if it requires the data to be extracted on the
> > > > > client side. I am saying this because the JobMasters may be running
> > > > > anywhere in a cluster while the clients may run on designated
> > machines
> > > > > which can have specific configurations, e.g. open ports to
> > communicate
> > > > > with a specific Atlas server.
> > > > >
> > > > > Cheers,
> > > > > Kostas
> > > > >
> > > > > On Thu, Mar 12, 2020 at 3:19 PM Stephan Ewen <[hidden email]>
> > wrote:
> > > > > >
> > > > > > Hi Gyula!
> > > > > >
> > > > > > My main motivation was to try and avoid mixing an internal
> > interface
> > > > > > (Pipeline) with public API. It looks like this is trying to go
> > "public
> > > > > > stable", but doesn't really do it exactly because of mixing
> > "pipeline"
> > > > into
> > > > > > this.
> > > > > > You would need to cast "Pipeline" and work on internal classes in
> > the
> > > > > > implementation.
> > > > > >
> > > > > > If we use an "internal API" or a "semi-stable SPI" class, it
> looks
> > at a
> > > > > > first glance a bit cleaner and more maintainable (opening up less
> > > > surface)
> > > > > > to make the PipelineExecutor a "stable SPI".
> > > > > > I have not checked out all the details, though.
> > > > > >
> > > > > > Best,
> > > > > > Stephan
> > > > > >
> > > > > >
> > > > > > On Thu, Mar 12, 2020 at 2:47 PM Gyula Fóra <[hidden email]
> >
> > > > wrote:
> > > > > >
> > > > > > > Hi Stephan!
> > > > > > >
> > > > > > > Thanks for checking this out. I agree that wrapping the other
> > > > > > > PipelineExecutors with a delegating AtlasExecutor would be a
> good
> > > > > > > alternative approach to implement this but I actually feel that
> > it
> > > > suffers
> > > > > > > even more problems than exposing the Pipeline instance in the
> > > > JobListener.
> > > > > > >
> > > > > > > The main idea with the Atlas integration would be to have the
> > Atlas
> > > > hook
> > > > > > > logic in the Atlas project where it would be maintained. This
> > means
> > > > that
> > > > > > > any approach we take has to rely on public APIs. The
> JobListener
> > is
> > > > already
> > > > > > > a public evolving API while the PipelineExecutor and the
> factory
> > is
> > > > purely
> > > > > > > internal. Even if we make it public it will still expose the
> > > > Pipeline so we
> > > > > > > did not gain much on the public/internal API front.
> > > > > > >
> > > > > > > I also feel that since the Atlas hook logic should only observe
> > the
> > > > > > > pipeline and collect information the JobListener interface
> seems
> > an
> > > > ideal
> > > > > > > match and the implementation can be pretty lightweight. From a
> > purely
> > > > > > > implementation perspective adding an Executor would be more
> > heavy as
> > > > it has
> > > > > > > to properly delegate to an other executor making sure that we
> > don't
> > > > break
> > > > > > > anything.
> > > > > > >
> > > > > > > Don't take me wrong, I am not opposed to reworking the
> > > > implementations we
> > > > > > > have as it's very simple at this point but I also want to make
> > sure
> > > > that we
> > > > > > > take the approach that is simple from a maintainability
> > standpoint.
> > > > Of
> > > > > > > course my argument rests on the assumption that the AtlasHook
> > itself
> > > > will
> > > > > > > live outside of the Flink project, thats another question.
> > > > > > >
> > > > > > > Cheers,
> > > > > > > Gyula
> > > > > > >
> > > > > > > On Thu, Mar 12, 2020 at 11:34 AM Stephan Ewen <
> [hidden email]>
> > > > wrote:
> > > > > > >
> > > > > > > > Hi all!
> > > > > > > >
> > > > > > > > In general, nice idea to support this integration with Atlas.
> > > > > > > >
> > > > > > > > I think we could make this a bit easier/lightweight with a
> > small
> > > > change.
> > > > > > > > One of the issues that is not super nice is that this starts
> > > > exposing the
> > > > > > > > (currently empty) Pipeline interface in the public API.
> > > > > > > > The Pipeline is an SPI interface that would be good to hide
> in
> > the
> > > > API.
> > > > > > > >
> > > > > > > > Since 1.10, Flink has the notion of Executors, which take the
> > > > pipeline
> > > > > > > and
> > > > > > > > execute them. Meaning each pipeline is passed on anyways. And
> > > > executors
> > > > > > > are
> > > > > > > > already configurable in the Flink configuration.
> > > > > > > > So, instead of passing the pipeline both "down" (to the
> > executor)
> > > > and "to
> > > > > > > > the side" (JobListener), could we just have a wrapping
> > > > "AtlasExecutor"
> > > > > > > that
> > > > > > > > takes the pipeline, does whatever it wants, and then passes
> it
> > to
> > > > the
> > > > > > > > proper executor? This would also have the advantage that it
> > > > supports
> > > > > > > making
> > > > > > > > changes to the pipeline, if needed in the future. For
> example,
> > if
> > > > there
> > > > > > > is
> > > > > > > > ever the need to add additional configuration fields, set
> > > > properties, add
> > > > > > > > "labels" or so, this could be easily done in the suggested
> > > > approach.
> > > > > > > >
> > > > > > > > I tried to sketch this in the picture below, pardon my bad
> > drawing.
> > > > > > > >
> > > > > > > > [image: Listener_Executor.png]
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > >
> >
> https://xjcrkw.bn.files.1drv.com/y4pWH57aEvLU5Ww4REC9XLi7nJMLGHq2smPSzaslU8ogywFDcMkP-_Rsl8B1njf4qphodim6bgnLTNFwNoEuwFdTuA2Xmf7CJ_8lTJjrKlFlDwrugVeBQzEhAY7n_5j2bumwDBf29jn_tZ1ueZxe2slhLkPC-9K6Dry_vpvRvZRY-CSnQXxj9jDf7P53Vz1K9Ez/Listener_Executor.png?psid=1
> > > > > > > >
> > > > > > > >
> > > > > > > > Best,
> > > > > > > > Stephan
> > > > > > > >
> > > > > > > >
> > > > > > > > On Wed, Mar 11, 2020 at 11:41 AM Aljoscha Krettek <
> > > > [hidden email]>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > >> Thanks! I'm reading the document now and will get back to
> you.
> > > > > > > >>
> > > > > > > >> Best,
> > > > > > > >> Aljoscha
> > > > > > > >>
> > > > > > > >
> > > > > > >
> > > >
> >
>

[Stephan Ewen]

Few thoughts on the discussion:

## Changes on the Master

If possible, let's avoid changes to the master (JobManager / Dispatcher).
These components are complex, we should strive to keep anything out of them
that we can keep out of them.

## Problems in different deployments (applications / sessions)

This should be pretty straightforward after FLIP-84, correct? There should
be no more "exception throwing" environments that sneak the job graph out
of the main method.

## Proposal: Executor Listeners

We could think of a mix between the two approaches: Executor Listerners.
When an executor is invoked with the Pipeline, the listener is also
notified. That would keep this out of the API and be properly within the
SPI layer.
The listeners could be loaded from config, or via service loaders.


On Fri, Mar 13, 2020 at 8:59 AM tison <[hidden email]> wrote:

> Hi Gyula and all,
>
> Thanks for the discussion so far.
>
> It seems that the requirement is to deliver some metadata of the submitted
> job,
> and such metadata can be simply extracted from StreamGraph.
>
> I'm unfamiliar with metadata Atlas needs so I make some assumptions.
>
> Assumption:
> Metadata needed by Atlas is actually some Flink scope information, such as
> input/
> output of a node. And this metadata is compile time information so that we
> know it
> during compiling the StreamGraph.
>
> If the assumption stands, I'm curious whether or not it is an option we
> standardize
> the JSON representation of StreamGraph which will contain metadata
> required. And
> pass the JSON representation from generation phase to JobGraph and then
> ExecutionGraph and finally retrievable from RestServer(so that we can
> extend
> JobClient to retrieve the plan by querying the cluster instead of have a
> pre-configured
> one).
>
> It is like `jsonPlan` in ExecutionGraph now(which is exposed by JobPlan
> REST
> endpoint). And I believe rather than JobGraph dump which is a physical
> plan,
> exposing access to StreamGraph dump which is a logical plan is possibly
> more
> interested from user perspective.
>
> Best,
> tison.
>
>
> Gyula Fóra <[hidden email]> 于2020年3月13日周五 下午3:20写道：
>
> > Thanks again Kostas for diving deep into this, it is great feedback!
> >
> > I agree with the concerns regarding the custom executor, it has to be
> able
> > to properly handle the "original" executor somehow.
> > This might be quite tricky if we want to implement the AtlasExecutor
> > outside Flink. In any case does not really feel clean or lightweight at
> > first glance.
> >
> > As for the JobClient/JobListener/Pipeline question, as you brought up the
> > possibility for later attaching the JobClient, maybe the best route for
> > this would be to
> > add the Pipeline as a method parameter in the JobListener. It would break
> > code compatibility but at least would have a consistent behavior.
> >
> > Now to the big problem of not having executors / joblisteners work in
> > kuberentes-per-job,  web, etc modes. I was not aware of this problem
> until
> > now, this also seems to affect the whole concept of the JobListener
> > interface. What good is a JobListener if it only listens to certain kind
> of
> > deployments :)
> >
> > Incidentally, in my first proposal (and prototype) I had the atlashook
> > running on the JobMaster with an extra addition to a JobGraphGenerator
> hook
> > that could be registered in the StreamExecutionEnvironment. This meant
> that
> > we could work on the StreamGraph, register metadata in the JobGraph, and
> > execute the actual atlas registration logic in the JobMaster when the job
> > starts.
> >
> > Looking back this is a much more complex, and uglier, logic than having a
> > simple JobListener. But it would at least work in all possible job
> > submission scenarios, as long as the JobGraph was generated through the
> > StreamGraph logic (which should be always).
> >
> > Cheers,
> > Gyula
> >
> >
> > On Thu, Mar 12, 2020 at 8:53 PM Kostas Kloudas <[hidden email]>
> wrote:
> >
> > > Thanks Gyula,
> > >
> > > Looking forward to your comments.
> > > Just to let you know, I would not like having a method that in some
> > > cases works as expected and in some other ones it does not. It would
> > > be nice if we could expose consistent behaviour to the users.
> > >
> > > On Thu, Mar 12, 2020 at 8:44 PM Gyula Fóra <[hidden email]>
> wrote:
> > > >
> > > > Thanks Kostas, I have to review the possible limitations with the
> > > Executor
> > > > before I can properly answer.
> > > >
> > > > Regarding you comments for the listener pattern, we proposed in the
> > > > document to include the getPipeline() in the JobClient itself as you
> > > > suggested to fit the pattern :) For not always being able to return
> the
> > > > pipeline, this might be expected depending on how the JobClient, so
> we
> > > need
> > > > to handle it some way.
> > > >
> > > >
> > > > On Thu, Mar 12, 2020 at 8:30 PM Kostas Kloudas <[hidden email]>
> > > wrote:
> > > >
> > > > > Hi again,
> > > > >
> > > > > Just to clarify, I am not against exposing the Pipeline if this
> will
> > > > > lead to a "clean" solution.
> > > > > And, I. forgot to say that the last solution, if adopted, would
> have
> > > > > to work on the JobGraph, which may not be that desirable.
> > > > >
> > > > > Kostas
> > > > >
> > > > > On Thu, Mar 12, 2020 at 8:26 PM Kostas Kloudas <[hidden email]
> >
> > > wrote:
> > > > > >
> > > > > > Hi all,
> > > > > >
> > > > > > I do not have a strong opinion on the topic yet, but I would like
> > to
> > > > > > share my thoughts on this.
> > > > > >
> > > > > > In the solution proposing a wrapping AtlasExecutor around the
> Flink
> > > > > > Executors, if we allow the user to use the CLI to submit jobs,
> then
> > > > > > this means that the CLI code may have to change so that it
> injects
> > > the
> > > > > > executor option to AtlasExecutor (transparently to the user), and
> > > then
> > > > > > the AtlasExecutor should take what the user has actually set as
> > > > > > pipeline executor and find the adequate executor. If this is not
> > done
> > > > > > transparently, then the user should do sth explicit to point
> Flink
> > to
> > > > > > Atlas and then to the correct executor, which implies that we
> > should
> > > > > > add user-facing stuff (like cli options) to Flink.
> > > > > >
> > > > > > For the solution of adding getPipeline() to the JobListener, I
> > think
> > > > > > that from a design perspective, it does not fit in the listener
> > > > > > itself. The listener is a "passive" entity that is expected to
> > listen
> > > > > > to specific "events". Adding a getter does not fit there. Other
> > > > > > options for the getPipeline() method are:
> > > > > > 1) add it as a method to the JobClient
> > > > > > 2) add it as an argument to the methods of the JobListener (along
> > > with
> > > > > > the JobClient and the throwable)
> > > > > >
> > > > > > Alternative 1) would currently work because the JobClient is only
> > > > > > instantiated by the executor. But in the future, we may (and
> > probably
> > > > > > will because of implications of FLIP-85) allow a JobClient to get
> > > > > > "attached" to a running job. In this case, the getPipeline() will
> > not
> > > > > > have a pipeline to return.
> > > > > > Alternative 2) will break existing code, which I am not sure how
> > > > > > important this is as the JobListener is a new feature and I guess
> > > some
> > > > > > but not many users.
> > > > > >
> > > > > > As a sidenote, if I am not mistaken, apart from Yarn, none of the
> > > > > > above solutions would work in per-job mode for Kuberneter, Mesos
> or
> > > > > > with web-submissions. These modes go through "special" execution
> > > > > > environments that use them simply to extract the JobGraph which
> > then
> > > > > > they submit to the cluster. In this case, there is no executor
> > > > > > involved. Are these cases important to you?
> > > > > >
> > > > > > Finally, another solution, although more drastic and more
> involved,
> > > > > > could be to have a "JobListener" running on the jobMaster. This
> > will
> > > > > > collect the relevant info and send them to Atlas. But I am not
> sure
> > > > > > how Atlas works and if it requires the data to be extracted on
> the
> > > > > > client side. I am saying this because the JobMasters may be
> running
> > > > > > anywhere in a cluster while the clients may run on designated
> > > machines
> > > > > > which can have specific configurations, e.g. open ports to
> > > communicate
> > > > > > with a specific Atlas server.
> > > > > >
> > > > > > Cheers,
> > > > > > Kostas
> > > > > >
> > > > > > On Thu, Mar 12, 2020 at 3:19 PM Stephan Ewen <[hidden email]>
> > > wrote:
> > > > > > >
> > > > > > > Hi Gyula!
> > > > > > >
> > > > > > > My main motivation was to try and avoid mixing an internal
> > > interface
> > > > > > > (Pipeline) with public API. It looks like this is trying to go
> > > "public
> > > > > > > stable", but doesn't really do it exactly because of mixing
> > > "pipeline"
> > > > > into
> > > > > > > this.
> > > > > > > You would need to cast "Pipeline" and work on internal classes
> in
> > > the
> > > > > > > implementation.
> > > > > > >
> > > > > > > If we use an "internal API" or a "semi-stable SPI" class, it
> > looks
> > > at a
> > > > > > > first glance a bit cleaner and more maintainable (opening up
> less
> > > > > surface)
> > > > > > > to make the PipelineExecutor a "stable SPI".
> > > > > > > I have not checked out all the details, though.
> > > > > > >
> > > > > > > Best,
> > > > > > > Stephan
> > > > > > >
> > > > > > >
> > > > > > > On Thu, Mar 12, 2020 at 2:47 PM Gyula Fóra <
> [hidden email]
> > >
> > > > > wrote:
> > > > > > >
> > > > > > > > Hi Stephan!
> > > > > > > >
> > > > > > > > Thanks for checking this out. I agree that wrapping the other
> > > > > > > > PipelineExecutors with a delegating AtlasExecutor would be a
> > good
> > > > > > > > alternative approach to implement this but I actually feel
> that
> > > it
> > > > > suffers
> > > > > > > > even more problems than exposing the Pipeline instance in the
> > > > > JobListener.
> > > > > > > >
> > > > > > > > The main idea with the Atlas integration would be to have the
> > > Atlas
> > > > > hook
> > > > > > > > logic in the Atlas project where it would be maintained. This
> > > means
> > > > > that
> > > > > > > > any approach we take has to rely on public APIs. The
> > JobListener
> > > is
> > > > > already
> > > > > > > > a public evolving API while the PipelineExecutor and the
> > factory
> > > is
> > > > > purely
> > > > > > > > internal. Even if we make it public it will still expose the
> > > > > Pipeline so we
> > > > > > > > did not gain much on the public/internal API front.
> > > > > > > >
> > > > > > > > I also feel that since the Atlas hook logic should only
> observe
> > > the
> > > > > > > > pipeline and collect information the JobListener interface
> > seems
> > > an
> > > > > ideal
> > > > > > > > match and the implementation can be pretty lightweight. From
> a
> > > purely
> > > > > > > > implementation perspective adding an Executor would be more
> > > heavy as
> > > > > it has
> > > > > > > > to properly delegate to an other executor making sure that we
> > > don't
> > > > > break
> > > > > > > > anything.
> > > > > > > >
> > > > > > > > Don't take me wrong, I am not opposed to reworking the
> > > > > implementations we
> > > > > > > > have as it's very simple at this point but I also want to
> make
> > > sure
> > > > > that we
> > > > > > > > take the approach that is simple from a maintainability
> > > standpoint.
> > > > > Of
> > > > > > > > course my argument rests on the assumption that the AtlasHook
> > > itself
> > > > > will
> > > > > > > > live outside of the Flink project, thats another question.
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > > Gyula
> > > > > > > >
> > > > > > > > On Thu, Mar 12, 2020 at 11:34 AM Stephan Ewen <
> > [hidden email]>
> > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi all!
> > > > > > > > >
> > > > > > > > > In general, nice idea to support this integration with
> Atlas.
> > > > > > > > >
> > > > > > > > > I think we could make this a bit easier/lightweight with a
> > > small
> > > > > change.
> > > > > > > > > One of the issues that is not super nice is that this
> starts
> > > > > exposing the
> > > > > > > > > (currently empty) Pipeline interface in the public API.
> > > > > > > > > The Pipeline is an SPI interface that would be good to hide
> > in
> > > the
> > > > > API.
> > > > > > > > >
> > > > > > > > > Since 1.10, Flink has the notion of Executors, which take
> the
> > > > > pipeline
> > > > > > > > and
> > > > > > > > > execute them. Meaning each pipeline is passed on anyways.
> And
> > > > > executors
> > > > > > > > are
> > > > > > > > > already configurable in the Flink configuration.
> > > > > > > > > So, instead of passing the pipeline both "down" (to the
> > > executor)
> > > > > and "to
> > > > > > > > > the side" (JobListener), could we just have a wrapping
> > > > > "AtlasExecutor"
> > > > > > > > that
> > > > > > > > > takes the pipeline, does whatever it wants, and then passes
> > it
> > > to
> > > > > the
> > > > > > > > > proper executor? This would also have the advantage that it
> > > > > supports
> > > > > > > > making
> > > > > > > > > changes to the pipeline, if needed in the future. For
> > example,
> > > if
> > > > > there
> > > > > > > > is
> > > > > > > > > ever the need to add additional configuration fields, set
> > > > > properties, add
> > > > > > > > > "labels" or so, this could be easily done in the suggested
> > > > > approach.
> > > > > > > > >
> > > > > > > > > I tried to sketch this in the picture below, pardon my bad
> > > drawing.
> > > > > > > > >
> > > > > > > > > [image: Listener_Executor.png]
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > >
> > >
> >
> https://xjcrkw.bn.files.1drv.com/y4pWH57aEvLU5Ww4REC9XLi7nJMLGHq2smPSzaslU8ogywFDcMkP-_Rsl8B1njf4qphodim6bgnLTNFwNoEuwFdTuA2Xmf7CJ_8lTJjrKlFlDwrugVeBQzEhAY7n_5j2bumwDBf29jn_tZ1ueZxe2slhLkPC-9K6Dry_vpvRvZRY-CSnQXxj9jDf7P53Vz1K9Ez/Listener_Executor.png?psid=1
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Best,
> > > > > > > > > Stephan
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On Wed, Mar 11, 2020 at 11:41 AM Aljoscha Krettek <
> > > > > [hidden email]>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > >> Thanks! I'm reading the document now and will get back to
> > you.
> > > > > > > > >>
> > > > > > > > >> Best,
> > > > > > > > >> Aljoscha
> > > > > > > > >>
> > > > > > > > >
> > > > > > > >
> > > > >
> > >
> >
>

[Kostas Kloudas-4]

I think that the ExecutorListener idea could work.

With a bit more than FLIP-85, it is true that we can get rid of the
"exception throwing" environments and we need to introduce an
"EmbeddedExecutor" which is going to run on the JM. So, the 2 above,
coupled with an ExecutorListener can have the desired effect.

Cheers,
Kostas

On Fri, Mar 13, 2020 at 11:37 AM Stephan Ewen <[hidden email]> wrote:

>
> Few thoughts on the discussion:
>
> ## Changes on the Master
>
> If possible, let's avoid changes to the master (JobManager / Dispatcher).
> These components are complex, we should strive to keep anything out of them
> that we can keep out of them.
>
> ## Problems in different deployments (applications / sessions)
>
> This should be pretty straightforward after FLIP-84, correct? There should
> be no more "exception throwing" environments that sneak the job graph out
> of the main method.
>
> ## Proposal: Executor Listeners
>
> We could think of a mix between the two approaches: Executor Listerners.
> When an executor is invoked with the Pipeline, the listener is also
> notified. That would keep this out of the API and be properly within the
> SPI layer.
> The listeners could be loaded from config, or via service loaders.
>
>
> On Fri, Mar 13, 2020 at 8:59 AM tison <[hidden email]> wrote:
>
> > Hi Gyula and all,
> >
> > Thanks for the discussion so far.
> >
> > It seems that the requirement is to deliver some metadata of the submitted
> > job,
> > and such metadata can be simply extracted from StreamGraph.
> >
> > I'm unfamiliar with metadata Atlas needs so I make some assumptions.
> >
> > Assumption:
> > Metadata needed by Atlas is actually some Flink scope information, such as
> > input/
> > output of a node. And this metadata is compile time information so that we
> > know it
> > during compiling the StreamGraph.
> >
> > If the assumption stands, I'm curious whether or not it is an option we
> > standardize
> > the JSON representation of StreamGraph which will contain metadata
> > required. And
> > pass the JSON representation from generation phase to JobGraph and then
> > ExecutionGraph and finally retrievable from RestServer(so that we can
> > extend
> > JobClient to retrieve the plan by querying the cluster instead of have a
> > pre-configured
> > one).
> >
> > It is like `jsonPlan` in ExecutionGraph now(which is exposed by JobPlan
> > REST
> > endpoint). And I believe rather than JobGraph dump which is a physical
> > plan,
> > exposing access to StreamGraph dump which is a logical plan is possibly
> > more
> > interested from user perspective.
> >
> > Best,
> > tison.
> >
> >
> > Gyula Fóra <[hidden email]> 于2020年3月13日周五 下午3:20写道：
> >
> > > Thanks again Kostas for diving deep into this, it is great feedback!
> > >
> > > I agree with the concerns regarding the custom executor, it has to be
> > able
> > > to properly handle the "original" executor somehow.
> > > This might be quite tricky if we want to implement the AtlasExecutor
> > > outside Flink. In any case does not really feel clean or lightweight at
> > > first glance.
> > >
> > > As for the JobClient/JobListener/Pipeline question, as you brought up the
> > > possibility for later attaching the JobClient, maybe the best route for
> > > this would be to
> > > add the Pipeline as a method parameter in the JobListener. It would break
> > > code compatibility but at least would have a consistent behavior.
> > >
> > > Now to the big problem of not having executors / joblisteners work in
> > > kuberentes-per-job,  web, etc modes. I was not aware of this problem
> > until
> > > now, this also seems to affect the whole concept of the JobListener
> > > interface. What good is a JobListener if it only listens to certain kind
> > of
> > > deployments :)
> > >
> > > Incidentally, in my first proposal (and prototype) I had the atlashook
> > > running on the JobMaster with an extra addition to a JobGraphGenerator
> > hook
> > > that could be registered in the StreamExecutionEnvironment. This meant
> > that
> > > we could work on the StreamGraph, register metadata in the JobGraph, and
> > > execute the actual atlas registration logic in the JobMaster when the job
> > > starts.
> > >
> > > Looking back this is a much more complex, and uglier, logic than having a
> > > simple JobListener. But it would at least work in all possible job
> > > submission scenarios, as long as the JobGraph was generated through the
> > > StreamGraph logic (which should be always).
> > >
> > > Cheers,
> > > Gyula
> > >
> > >
> > > On Thu, Mar 12, 2020 at 8:53 PM Kostas Kloudas <[hidden email]>
> > wrote:
> > >
> > > > Thanks Gyula,
> > > >
> > > > Looking forward to your comments.
> > > > Just to let you know, I would not like having a method that in some
> > > > cases works as expected and in some other ones it does not. It would
> > > > be nice if we could expose consistent behaviour to the users.
> > > >
> > > > On Thu, Mar 12, 2020 at 8:44 PM Gyula Fóra <[hidden email]>
> > wrote:
> > > > >
> > > > > Thanks Kostas, I have to review the possible limitations with the
> > > > Executor
> > > > > before I can properly answer.
> > > > >
> > > > > Regarding you comments for the listener pattern, we proposed in the
> > > > > document to include the getPipeline() in the JobClient itself as you
> > > > > suggested to fit the pattern :) For not always being able to return
> > the
> > > > > pipeline, this might be expected depending on how the JobClient, so
> > we
> > > > need
> > > > > to handle it some way.
> > > > >
> > > > >
> > > > > On Thu, Mar 12, 2020 at 8:30 PM Kostas Kloudas <[hidden email]>
> > > > wrote:
> > > > >
> > > > > > Hi again,
> > > > > >
> > > > > > Just to clarify, I am not against exposing the Pipeline if this
> > will
> > > > > > lead to a "clean" solution.
> > > > > > And, I. forgot to say that the last solution, if adopted, would
> > have
> > > > > > to work on the JobGraph, which may not be that desirable.
> > > > > >
> > > > > > Kostas
> > > > > >
> > > > > > On Thu, Mar 12, 2020 at 8:26 PM Kostas Kloudas <[hidden email]
> > >
> > > > wrote:
> > > > > > >
> > > > > > > Hi all,
> > > > > > >
> > > > > > > I do not have a strong opinion on the topic yet, but I would like
> > > to
> > > > > > > share my thoughts on this.
> > > > > > >
> > > > > > > In the solution proposing a wrapping AtlasExecutor around the
> > Flink
> > > > > > > Executors, if we allow the user to use the CLI to submit jobs,
> > then
> > > > > > > this means that the CLI code may have to change so that it
> > injects
> > > > the
> > > > > > > executor option to AtlasExecutor (transparently to the user), and
> > > > then
> > > > > > > the AtlasExecutor should take what the user has actually set as
> > > > > > > pipeline executor and find the adequate executor. If this is not
> > > done
> > > > > > > transparently, then the user should do sth explicit to point
> > Flink
> > > to
> > > > > > > Atlas and then to the correct executor, which implies that we
> > > should
> > > > > > > add user-facing stuff (like cli options) to Flink.
> > > > > > >
> > > > > > > For the solution of adding getPipeline() to the JobListener, I
> > > think
> > > > > > > that from a design perspective, it does not fit in the listener
> > > > > > > itself. The listener is a "passive" entity that is expected to
> > > listen
> > > > > > > to specific "events". Adding a getter does not fit there. Other
> > > > > > > options for the getPipeline() method are:
> > > > > > > 1) add it as a method to the JobClient
> > > > > > > 2) add it as an argument to the methods of the JobListener (along
> > > > with
> > > > > > > the JobClient and the throwable)
> > > > > > >
> > > > > > > Alternative 1) would currently work because the JobClient is only
> > > > > > > instantiated by the executor. But in the future, we may (and
> > > probably
> > > > > > > will because of implications of FLIP-85) allow a JobClient to get
> > > > > > > "attached" to a running job. In this case, the getPipeline() will
> > > not
> > > > > > > have a pipeline to return.
> > > > > > > Alternative 2) will break existing code, which I am not sure how
> > > > > > > important this is as the JobListener is a new feature and I guess
> > > > some
> > > > > > > but not many users.
> > > > > > >
> > > > > > > As a sidenote, if I am not mistaken, apart from Yarn, none of the
> > > > > > > above solutions would work in per-job mode for Kuberneter, Mesos
> > or
> > > > > > > with web-submissions. These modes go through "special" execution
> > > > > > > environments that use them simply to extract the JobGraph which
> > > then
> > > > > > > they submit to the cluster. In this case, there is no executor
> > > > > > > involved. Are these cases important to you?
> > > > > > >
> > > > > > > Finally, another solution, although more drastic and more
> > involved,
> > > > > > > could be to have a "JobListener" running on the jobMaster. This
> > > will
> > > > > > > collect the relevant info and send them to Atlas. But I am not
> > sure
> > > > > > > how Atlas works and if it requires the data to be extracted on
> > the
> > > > > > > client side. I am saying this because the JobMasters may be
> > running
> > > > > > > anywhere in a cluster while the clients may run on designated
> > > > machines
> > > > > > > which can have specific configurations, e.g. open ports to
> > > > communicate
> > > > > > > with a specific Atlas server.
> > > > > > >
> > > > > > > Cheers,
> > > > > > > Kostas
> > > > > > >
> > > > > > > On Thu, Mar 12, 2020 at 3:19 PM Stephan Ewen <[hidden email]>
> > > > wrote:
> > > > > > > >
> > > > > > > > Hi Gyula!
> > > > > > > >
> > > > > > > > My main motivation was to try and avoid mixing an internal
> > > > interface
> > > > > > > > (Pipeline) with public API. It looks like this is trying to go
> > > > "public
> > > > > > > > stable", but doesn't really do it exactly because of mixing
> > > > "pipeline"
> > > > > > into
> > > > > > > > this.
> > > > > > > > You would need to cast "Pipeline" and work on internal classes
> > in
> > > > the
> > > > > > > > implementation.
> > > > > > > >
> > > > > > > > If we use an "internal API" or a "semi-stable SPI" class, it
> > > looks
> > > > at a
> > > > > > > > first glance a bit cleaner and more maintainable (opening up
> > less
> > > > > > surface)
> > > > > > > > to make the PipelineExecutor a "stable SPI".
> > > > > > > > I have not checked out all the details, though.
> > > > > > > >
> > > > > > > > Best,
> > > > > > > > Stephan
> > > > > > > >
> > > > > > > >
> > > > > > > > On Thu, Mar 12, 2020 at 2:47 PM Gyula Fóra <
> > [hidden email]
> > > >
> > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Stephan!
> > > > > > > > >
> > > > > > > > > Thanks for checking this out. I agree that wrapping the other
> > > > > > > > > PipelineExecutors with a delegating AtlasExecutor would be a
> > > good
> > > > > > > > > alternative approach to implement this but I actually feel
> > that
> > > > it
> > > > > > suffers
> > > > > > > > > even more problems than exposing the Pipeline instance in the
> > > > > > JobListener.
> > > > > > > > >
> > > > > > > > > The main idea with the Atlas integration would be to have the
> > > > Atlas
> > > > > > hook
> > > > > > > > > logic in the Atlas project where it would be maintained. This
> > > > means
> > > > > > that
> > > > > > > > > any approach we take has to rely on public APIs. The
> > > JobListener
> > > > is
> > > > > > already
> > > > > > > > > a public evolving API while the PipelineExecutor and the
> > > factory
> > > > is
> > > > > > purely
> > > > > > > > > internal. Even if we make it public it will still expose the
> > > > > > Pipeline so we
> > > > > > > > > did not gain much on the public/internal API front.
> > > > > > > > >
> > > > > > > > > I also feel that since the Atlas hook logic should only
> > observe
> > > > the
> > > > > > > > > pipeline and collect information the JobListener interface
> > > seems
> > > > an
> > > > > > ideal
> > > > > > > > > match and the implementation can be pretty lightweight. From
> > a
> > > > purely
> > > > > > > > > implementation perspective adding an Executor would be more
> > > > heavy as
> > > > > > it has
> > > > > > > > > to properly delegate to an other executor making sure that we
> > > > don't
> > > > > > break
> > > > > > > > > anything.
> > > > > > > > >
> > > > > > > > > Don't take me wrong, I am not opposed to reworking the
> > > > > > implementations we
> > > > > > > > > have as it's very simple at this point but I also want to
> > make
> > > > sure
> > > > > > that we
> > > > > > > > > take the approach that is simple from a maintainability
> > > > standpoint.
> > > > > > Of
> > > > > > > > > course my argument rests on the assumption that the AtlasHook
> > > > itself
> > > > > > will
> > > > > > > > > live outside of the Flink project, thats another question.
> > > > > > > > >
> > > > > > > > > Cheers,
> > > > > > > > > Gyula
> > > > > > > > >
> > > > > > > > > On Thu, Mar 12, 2020 at 11:34 AM Stephan Ewen <
> > > [hidden email]>
> > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi all!
> > > > > > > > > >
> > > > > > > > > > In general, nice idea to support this integration with
> > Atlas.
> > > > > > > > > >
> > > > > > > > > > I think we could make this a bit easier/lightweight with a
> > > > small
> > > > > > change.
> > > > > > > > > > One of the issues that is not super nice is that this
> > starts
> > > > > > exposing the
> > > > > > > > > > (currently empty) Pipeline interface in the public API.
> > > > > > > > > > The Pipeline is an SPI interface that would be good to hide
> > > in
> > > > the
> > > > > > API.
> > > > > > > > > >
> > > > > > > > > > Since 1.10, Flink has the notion of Executors, which take
> > the
> > > > > > pipeline
> > > > > > > > > and
> > > > > > > > > > execute them. Meaning each pipeline is passed on anyways.
> > And
> > > > > > executors
> > > > > > > > > are
> > > > > > > > > > already configurable in the Flink configuration.
> > > > > > > > > > So, instead of passing the pipeline both "down" (to the
> > > > executor)
> > > > > > and "to
> > > > > > > > > > the side" (JobListener), could we just have a wrapping
> > > > > > "AtlasExecutor"
> > > > > > > > > that
> > > > > > > > > > takes the pipeline, does whatever it wants, and then passes
> > > it
> > > > to
> > > > > > the
> > > > > > > > > > proper executor? This would also have the advantage that it
> > > > > > supports
> > > > > > > > > making
> > > > > > > > > > changes to the pipeline, if needed in the future. For
> > > example,
> > > > if
> > > > > > there
> > > > > > > > > is
> > > > > > > > > > ever the need to add additional configuration fields, set
> > > > > > properties, add
> > > > > > > > > > "labels" or so, this could be easily done in the suggested
> > > > > > approach.
> > > > > > > > > >
> > > > > > > > > > I tried to sketch this in the picture below, pardon my bad
> > > > drawing.
> > > > > > > > > >
> > > > > > > > > > [image: Listener_Executor.png]
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > >
> > > >
> > >
> > https://xjcrkw.bn.files.1drv.com/y4pWH57aEvLU5Ww4REC9XLi7nJMLGHq2smPSzaslU8ogywFDcMkP-_Rsl8B1njf4qphodim6bgnLTNFwNoEuwFdTuA2Xmf7CJ_8lTJjrKlFlDwrugVeBQzEhAY7n_5j2bumwDBf29jn_tZ1ueZxe2slhLkPC-9K6Dry_vpvRvZRY-CSnQXxj9jDf7P53Vz1K9Ez/Listener_Executor.png?psid=1
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Best,
> > > > > > > > > > Stephan
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > On Wed, Mar 11, 2020 at 11:41 AM Aljoscha Krettek <
> > > > > > [hidden email]>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > >> Thanks! I'm reading the document now and will get back to
> > > you.
> > > > > > > > > >>
> > > > > > > > > >> Best,
> > > > > > > > > >> Aljoscha
> > > > > > > > > >>
> > > > > > > > > >
> > > > > > > > >
> > > > > >
> > > >
> > >
> >

[Jacky Lau]

Hi:
  i think flink integrate atlas also need add catalog information such as
spark atlas project
.https://github.com/hortonworks-spark/spark-atlas-connector
 when user use catalog such as JDBCCatalog/HiveCatalog, flink atlas project
will sync this information to atlas.
  But i don't find any Event Interface for flink to implement it as
spark-atlas-connector does. Does anyone know how to do it



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[Márton Balassi]

Hi Jack,

Yes, we know how to do it and even have the implementation ready and being
reviewed by the Atlas community at the moment. :-)
Would you be interested in having a look?

On Thu, Mar 19, 2020 at 12:56 PM jackylau <[hidden email]> wrote:

> Hi:
>   i think flink integrate atlas also need add catalog information such as
> spark atlas project
> .https://github.com/hortonworks-spark/spark-atlas-connector
>  when user use catalog such as JDBCCatalog/HiveCatalog, flink atlas project
> will sync this information to atlas.
>   But i don't find any Event Interface for flink to implement it as
> spark-atlas-connector does. Does anyone know how to do it
>
>
>
> --
> Sent from: http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/
>

[Jacky Lau]

Hi Márton Balassi:
   I am very glad to look at it and where to find .
   And it is my issue , which you can see
https://issues.apache.org/jira/browse/FLINK-16774



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[Gyula Fóra]

Hi Jack!

You can find the document here:
https://docs.google.com/document/d/1wSgzPdhcwt-SlNBBqL-Zb7g8fY6bN8JwHEg7GCdsBG8/edit?usp=sharing

The document links to an already working Atlas hook prototype (and
accompanying flink fork). The links for that are also here:
Flink: https://github.com/gyfora/flink/tree/atlas-changes
Atlas: https://github.com/gyfora/atlas/tree/flink-bridge

We need to adapt this according to the above discussion this was an early
prototype.
Gyula

On Fri, Mar 27, 2020 at 11:07 AM jackylau <[hidden email]> wrote:

> Hi Márton Balassi:
>    I am very glad to look at it and where to find .
>    And it is my issue , which you can see
> https://issues.apache.org/jira/browse/FLINK-16774
>
>
>
> --
> Sent from: http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/
>

[Jacky Lau]

thanks Gyula Fóra. i have read it. And i think it is lark of flink catalog
info, which you can see spark atlas project here
https://github.com/hortonworks-spark/spark-atlas-connector



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