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From Kurt Young <ykt...@gmail.com>
Subject Re: [DISCUSS] FLIP-6 - Flink Deployment and Process Model - Standalone, Yarn, Mesos, Kubernetes, etc.
Date Mon, 01 Aug 2016 01:44:49 GMT
Thanks for the great proposal.

There are still 2 issues i concerned with which i want to discuss with.

#1 Who should decide the resources one operator uses, user or framework?
Like how much cpu or memory will cost by my "map" operator, does it seem a
little bit too low level for the users, should we expose some APIs for
these?

#2 Who decides to combine the slots into a real container in Yarn and Mesos
mode? Currently, flink has an optimize for resource utilization which
called SlotSharingGroup. This took effects before flink allocate resources,
we combine as many operators as we could into one single *SharedSlot*
(which i think it's still a Slot). It seems all the combination or
optimization are done before we allocate resources, so should we
distinguish the differences between slots and containers(if we want
introduces this concept, but i think it's needed by standalone mode). If
the answer is yes, it will lead us to the situation that both JobManager
and ResourceManager will know how to utilize resources. For logic like
SlotSharingGroup, it's more appropriate to let Scheduler handle because
it's has a lot informations about JobGraph and some constraint on it. But
for some other logics which are more pure resources aware or Cluster
specified, we may consider to let ResourceManager handle these. E.g. there
are some limitation about Yarn's allocation, we can only allocate
containers with "integer" vcores, so it's not possible for us to have some
0.1 or 0.2 vcore for now. We have bypassed this by combining some operators
into one slot or it will cause waste of resources. But, i think it's better
if we can make only one role aware all the resources utilizations.

Thanks
Kurt

On Thu, Jul 28, 2016 at 5:22 PM, Maximilian Michels <mxm@apache.org> wrote:

> Hi Stephan,
>
> Thanks for the nice wrap-up of ideas and discussions we had over the
> last months (not all on the mailing list though because we were just
> getting started with the FLIP process). The document is very
> comprehensive and explains the changes in great details, even up to
> the message passing level.
>
> What I really like about the FLIP is that we delegate multi-tenancy
> away from the JobManager to the resource management framework and the
> dispatchers. This will help to make the JobManager component cleaner
> and simpler. The prospect of having the user jars directly in the
> system classpath of the workers, instead of dealing with custom class
> loaders, is very nice.
>
> The model we have for acquiring and releasing resources wouldn't work
> particularly well with all the new deployment options, so +1 on a new
> task slot request/offer system and +1 for making the ResourceManager
> responsible for TaskManager registration and slot management. This is
> well aligned with the initial idea of the ResourceManager component.
>
> We definitely need good testing for these changes since the
> possibility of bugs increases with the additional number of messages
> introduced.
>
> The only thing that bugs me is whether we make the Standalone mode a
> bit less nice to use. The initial bootstrapping of the nodes via the
> local dispatchers and the subsequent registration of TaskManagers and
> allocation of slots could cause some delay. It's not a major concern
> though because it will take little time compared to the actual job run
> time (unless you run a tiny WordCount).
>
> Cheers,
> Max
>
>
>
>
> On Fri, Jul 22, 2016 at 9:26 PM, Stephan Ewen <sewen@apache.org> wrote:
> > Hi all!
> >
> > Here comes a pretty big FLIP: "Improvements to the Flink Deployment and
> > Process Model", to better support Yarn, Mesos, Kubernetes, and whatever
> > else Google, Elon Musk, and all the other folks will think up next.
> >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=65147077
> >
> > It is a pretty big FLIP where I took input and thoughts from many people,
> > like Till, Max, Xiaowei (and his colleagues), Eron, and others.
> >
> > The core ideas revolve around
> >   - making the JobManager in its core a per-job component (handle multi
> > tenancey outside the JobManager)
> >   - making resource acquisition and release more dynamic
> >   - tying deployments more naturally to jobs where desirable
> >
> >
> > Let's get the discussion started...
> >
> > Greetings,
> > Stephan
>

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