Hi Everyone, @John
This is a problem that we've spent some time trying to crack; in the end, we've decided to go against doing any upgrades to JobGraphStore from JobMaster to avoid having multiple writers that are guarded by different leader election lock (Dispatcher and JobMaster might live in a different process). The contract we've decided to choose instead is leveraging the idempotency of the endpoint and having the user of the API retry in case we're unable to persist new requirements in the JobGraphStore [1]. We eventually need to move JobGraphStore out of the dispatcher, but that's way out of the scope of this FLIP. The solution is a deliberate trade-off. The worst scenario is that the Dispatcher fails over in between retries, which would simply rescale the job to meet the previous resource requirements (more extended unavailability of underlying HA storage would have worse consequences than this). Does that answer your question? @Matthias Good catch! I'm fixing it now, thanks! [1] https://github.com/dmvk/flink/commit/5e7edcb77d8522c367bc6977f80173b14dc03ce9#diff-a4b690fb2c4975d25b05eb4161617af0d704a85ff7b1cad19d3c817c12f1e29cR1151 Best, D. On Tue, Feb 21, 2023 at 12:24 AM John Roesler <vvcep...@apache.org> wrote: > Thanks for the FLIP, David! > > I just had one small question. IIUC, the REST API PUT request will go > through the new DispatcherGateway method to be handled. Then, after > validation, the dispatcher would call the new JobMasterGateway method to > actually update the job. > > Which component will write the updated JobGraph? I just wanted to make > sure it’s the JobMaster because it it were the dispatcher, there could be a > race condition with the async JobMaster method. > > Thanks! > -John > > On Mon, Feb 20, 2023, at 07:34, Matthias Pohl wrote: > > Thanks for your clarifications, David. I don't have any additional major > > points to add. One thing about the FLIP: The RPC layer API for updating > the > > JRR returns a future with a JRR? I don't see value in returning a JRR > here > > since it's an idempotent operation? Wouldn't it be enough to return > > CompletableFuture<Void> here? Or am I missing something? > > > > Matthias > > > > On Mon, Feb 20, 2023 at 1:48 PM Maximilian Michels <m...@apache.org> > wrote: > > > >> Thanks David! If we could get the pre-allocation working as part of > >> the FLIP, that would be great. > >> > >> Concerning the downscale case, I agree this is a special case for the > >> (single-job) application mode where we could re-allocate slots in a > >> way that could leave entire task managers unoccupied which we would > >> then be able to release. The goal essentially is to reduce slot > >> fragmentation on scale down by packing the slots efficiently. The > >> easiest way to add this optimization when running in application mode > >> would be to drop as many task managers during the restart such that > >> NUM_REQUIRED_SLOTS >= NUM_AVAILABLE_SLOTS stays true. We can look into > >> this independently of the FLIP. > >> > >> Feel free to start the vote. > >> > >> -Max > >> > >> On Mon, Feb 20, 2023 at 9:10 AM David Morávek <d...@apache.org> wrote: > >> > > >> > Hi everyone, > >> > > >> > Thanks for the feedback! I've updated the FLIP to use idempotent PUT > API > >> instead of PATCH and to properly handle lower bound settings, to support > >> the "pre-allocation" of the resources. > >> > > >> > @Max > >> > > >> > > How hard would it be to address this issue in the FLIP? > >> > > >> > I've included this in the FLIP. It might not be too hard to implement > >> this in the end. > >> > > >> > > B) drop as many superfluous task managers as needed > >> > > >> > I've intentionally left this part out for now because this ultimately > >> needs to be the responsibility of the Resource Manager. After all, in > the > >> Session Cluster scenario, the Scheduler doesn't have the bigger picture > of > >> other tasks of other jobs running on those TMs. This will most likely > be a > >> topic for another FLIP. > >> > > >> > WDYT? If there are no other questions or concerns, I'd like to start > the > >> vote on Wednesday. > >> > > >> > Best, > >> > D. > >> > > >> > On Wed, Feb 15, 2023 at 3:34 PM Maximilian Michels <m...@apache.org> > >> wrote: > >> >> > >> >> I missed that the FLIP states: > >> >> > >> >> > Currently, even though we’d expose the lower bound for clarity and > >> API completeness, we won’t allow setting it to any other value than one > >> until we have full support throughout the stack. > >> >> > >> >> How hard would it be to address this issue in the FLIP? > >> >> > >> >> There is not much value to offer setting a lower bound which won't be > >> >> respected / throw an error when it is set. If we had support for a > >> >> lower bound, we could enforce a resource contract externally via > >> >> setting lowerBound == upperBound. That ties back to the Rescale API > >> >> discussion we had. I want to better understand what the major > concerns > >> >> would be around allowing this. > >> >> > >> >> Just to outline how I imagine the logic to work: > >> >> > >> >> A) The resource constraints are already met => Nothing changes > >> >> B) More resources available than required => Cancel the job, drop as > >> >> many superfluous task managers as needed, restart the job > >> >> C) Less resources available than required => Acquire new task > >> >> managers, wait for them to register, cancel and restart the job > >> >> > >> >> I'm open to helping out with the implementation. > >> >> > >> >> -Max > >> >> > >> >> On Mon, Feb 13, 2023 at 7:45 PM Maximilian Michels <m...@apache.org> > >> wrote: > >> >> > > >> >> > Based on further discussion I had with Chesnay on this PR [1], I > think > >> >> > jobs would currently go into a restarting state after the resource > >> >> > requirements have changed. This wouldn't achieve what we had in > mind, > >> >> > i.e. sticking to the old resource requirements until enough slots > are > >> >> > available to fulfil the new resource requirements. So this may not > be > >> >> > 100% what we need but it could be extended to do what we want. > >> >> > > >> >> > -Max > >> >> > > >> >> > [1] > https://github.com/apache/flink/pull/21908#discussion_r1104792362 > >> >> > > >> >> > On Mon, Feb 13, 2023 at 7:16 PM Maximilian Michels <m...@apache.org > > > >> wrote: > >> >> > > > >> >> > > Hi David, > >> >> > > > >> >> > > This is awesome! Great writeup and demo. This is pretty much > what we > >> >> > > need for the autoscaler as part of the Flink Kubernetes operator > >> [1]. > >> >> > > Scaling Flink jobs effectively is hard but fortunately we have > >> solved > >> >> > > the issue as part of the Flink Kubernetes operator. The only > >> critical > >> >> > > piece we are missing is a better way to execute scaling > decisions, > >> as > >> >> > > discussed in [2]. > >> >> > > > >> >> > > Looking at your proposal, we would set lowerBound == upperBound > for > >> >> > > the parallelism because we want to fully determine the > parallelism > >> >> > > externally based on the scaling metrics. Does that sound right? > >> >> > > > >> >> > > What is the timeline for these changes? Is there a JIRA? > >> >> > > > >> >> > > Cheers, > >> >> > > Max > >> >> > > > >> >> > > [1] > >> > https://nightlies.apache.org/flink/flink-kubernetes-operator-docs-main/docs/custom-resource/autoscaler/ > >> >> > > [2] > >> https://lists.apache.org/thread/2f7dgr88xtbmsohtr0f6wmsvw8sw04f5 > >> >> > > > >> >> > > On Mon, Feb 13, 2023 at 1:16 PM feng xiangyu < > xiangyu...@gmail.com> > >> wrote: > >> >> > > > > >> >> > > > Hi David, > >> >> > > > > >> >> > > > Thanks for your reply. I think your response totally make > >> sense. This > >> >> > > > flip targets on declaring required resource to ResourceManager > >> instead of > >> >> > > > using ResourceManager to add/remove TMs directly. > >> >> > > > > >> >> > > > Best, > >> >> > > > Xiangyu > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > > David Morávek <david.mora...@gmail.com> 于2023年2月13日周一 15:46写道： > >> >> > > > > >> >> > > > > Hi everyone, > >> >> > > > > > >> >> > > > > @Shammon > >> >> > > > > > >> >> > > > > I'm not entirely sure what "config file" you're referring to. > >> You can, of > >> >> > > > > course, override the default parallelism in > "flink-conf.yaml", > >> but for > >> >> > > > > sinks and sources, the parallelism needs to be tweaked on the > >> connector > >> >> > > > > level ("WITH" statement). > >> >> > > > > > >> >> > > > > This is something that should be achieved with tooling around > >> Flink. We > >> >> > > > > want to provide an API on the lowest level that generalizes > >> well. Achieving > >> >> > > > > what you're describing should be straightforward with this > API. > >> >> > > > > > >> >> > > > > @Xiangyu > >> >> > > > > > >> >> > > > > Is it possible for this REST API to declare TM resources in > the > >> future? > >> >> > > > > > >> >> > > > > > >> >> > > > > Would you like to add/remove TMs if you use an active > Resource > >> Manager? > >> >> > > > > This would be out of the scope of this effort since it > targets > >> the > >> >> > > > > scheduler component only (we make no assumptions about the > used > >> Resource > >> >> > > > > Manager). Also, the AdaptiveScheduler is only intended to be > >> used for > >> >> > > > > Streaming. > >> >> > > > > > >> >> > > > > And for streaming jobs, I'm wondering if there is any > >> situation we need to > >> >> > > > > > rescale the TM resources of a flink cluster at first and > then > >> the > >> >> > > > > adaptive > >> >> > > > > > scheduler will rescale the per-vertex ResourceProfiles > >> accordingly. > >> >> > > > > > > >> >> > > > > > >> >> > > > > We plan on adding support for the ResourceProfiles (dynamic > slot > >> >> > > > > allocation) as the next step. Again we won't make any > >> assumptions about the > >> >> > > > > used Resource Manager. In other words, this effort ends by > >> declaring > >> >> > > > > desired resources to the Resource Manager. > >> >> > > > > > >> >> > > > > Does that make sense? > >> >> > > > > > >> >> > > > > @Matthias > >> >> > > > > > >> >> > > > > We've done another pass on the proposed API and currently > lean > >> towards > >> >> > > > > having an idempotent PUT API. > >> >> > > > > - We don't care too much about multiple writers' scenarios in > >> terms of who > >> >> > > > > can write an authoritative payload; this is up to the user of > >> the API to > >> >> > > > > figure out > >> >> > > > > - It's indeed tricky to achieve atomicity with PATCH API; > >> switching to PUT > >> >> > > > > API seems to do the trick > >> >> > > > > - We won't allow partial "payloads" anymore, meaning you need > >> to define > >> >> > > > > requirements for all vertices in the JobGraph; This is > >> completely fine for > >> >> > > > > the programmatic workflows. For DEBUG / DEMO purposes, you > can > >> use the GET > >> >> > > > > endpoint and tweak the response to avoid writing the whole > >> payload by hand. > >> >> > > > > > >> >> > > > > WDYT? > >> >> > > > > > >> >> > > > > > >> >> > > > > Best, > >> >> > > > > D. > >> >> > > > > > >> >> > > > > On Fri, Feb 10, 2023 at 11:21 AM feng xiangyu < > >> xiangyu...@gmail.com> > >> >> > > > > wrote: > >> >> > > > > > >> >> > > > > > Hi David, > >> >> > > > > > > >> >> > > > > > Thanks for creating this flip. I think this work it is very > >> useful, > >> >> > > > > > especially in autoscaling scenario. I would like to share > >> some questions > >> >> > > > > > from my view. > >> >> > > > > > > >> >> > > > > > 1, Is it possible for this REST API to declare TM resources > >> in the > >> >> > > > > future? > >> >> > > > > > I'm asking because we are building the autoscaling feature > >> for Flink OLAP > >> >> > > > > > Session Cluster in ByteDance. We need to rescale the > >> cluster's resource > >> >> > > > > on > >> >> > > > > > TM level instead of Job level. It would be very helpful if > we > >> have a REST > >> >> > > > > > API for out external Autoscaling service to use. > >> >> > > > > > > >> >> > > > > > 2, And for streaming jobs, I'm wondering if there is any > >> situation we > >> >> > > > > need > >> >> > > > > > to rescale the TM resources of a flink cluster at first and > >> then the > >> >> > > > > > adaptive scheduler will rescale the per-vertex > >> ResourceProfiles > >> >> > > > > > accordingly. > >> >> > > > > > > >> >> > > > > > best. > >> >> > > > > > Xiangyu > >> >> > > > > > > >> >> > > > > > Shammon FY <zjur...@gmail.com> 于2023年2月9日周四 11:31写道： > >> >> > > > > > > >> >> > > > > > > Hi David > >> >> > > > > > > > >> >> > > > > > > Thanks for your answer. > >> >> > > > > > > > >> >> > > > > > > > Can you elaborate more about how you'd intend to use > the > >> endpoint? I > >> >> > > > > > > think we can ultimately introduce a way of re-declaring > >> "per-vertex > >> >> > > > > > > defaults," but I'd like to understand the use case bit > more > >> first. > >> >> > > > > > > > >> >> > > > > > > For this issue, I mainly consider the consistency of user > >> configuration > >> >> > > > > > and > >> >> > > > > > > job runtime. For sql jobs, users usually set specific > >> parallelism for > >> >> > > > > > > source and sink, and set a global parallelism for other > >> operators. > >> >> > > > > These > >> >> > > > > > > config items are stored in a config file. For some > >> high-priority jobs, > >> >> > > > > > > users may want to manage them manually. > >> >> > > > > > > 1. When users need to scale the parallelism, they should > >> update the > >> >> > > > > > config > >> >> > > > > > > file and restart flink job, which may take a long time. > >> >> > > > > > > 2. After providing the REST API, users can just send a > >> request to the > >> >> > > > > job > >> >> > > > > > > via REST API quickly after updating the config file. > >> >> > > > > > > The configuration in the running job and config file > should > >> be the > >> >> > > > > same. > >> >> > > > > > > What do you think of this? > >> >> > > > > > > > >> >> > > > > > > best. > >> >> > > > > > > Shammon > >> >> > > > > > > > >> >> > > > > > > > >> >> > > > > > > > >> >> > > > > > > On Tue, Feb 7, 2023 at 4:51 PM David Morávek < > >> david.mora...@gmail.com> > >> >> > > > > > > wrote: > >> >> > > > > > > > >> >> > > > > > > > Hi everyone, > >> >> > > > > > > > > >> >> > > > > > > > Let's try to answer the questions one by one. > >> >> > > > > > > > > >> >> > > > > > > > *@ConradJam* > >> >> > > > > > > > > >> >> > > > > > > > when the number of "slots" is insufficient, can we can > >> stop users > >> >> > > > > > > rescaling > >> >> > > > > > > > > or throw something to tell user "less avaliable slots > >> to upgrade, > >> >> > > > > > > please > >> >> > > > > > > > > checkout your alivalbe slots" ? > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > The main property of AdaptiveScheduler is that it can > >> adapt to > >> >> > > > > > "available > >> >> > > > > > > > resources," which means you're still able to make > >> progress even > >> >> > > > > though > >> >> > > > > > > you > >> >> > > > > > > > didn't get all the slots you've asked for. Let's break > >> down the pros > >> >> > > > > > and > >> >> > > > > > > > cons of this property. > >> >> > > > > > > > > >> >> > > > > > > > - (plus) If you lose a TM for some reason, you can > still > >> recover even > >> >> > > > > > if > >> >> > > > > > > it > >> >> > > > > > > > doesn't come back. We still need to give it some time > to > >> eliminate > >> >> > > > > > > > unnecessary rescaling, which can be controlled by > setting > >> >> > > > > > > > "resource-stabilization-timeout." > >> >> > > > > > > > - (plus) The resources can arrive with a significant > >> delay. For > >> >> > > > > > example, > >> >> > > > > > > > you're unable to spawn enough TMs on time because > you've > >> run out of > >> >> > > > > > > > resources in your k8s cluster, and you need to wait for > >> the cluster > >> >> > > > > > auto > >> >> > > > > > > > scaler to kick in and add new nodes to the cluster. In > >> this scenario, > >> >> > > > > > > > you'll be able to start making progress faster, at the > >> cost of > >> >> > > > > multiple > >> >> > > > > > > > rescalings (once the remaining resources arrive). > >> >> > > > > > > > - (plus) This plays well with the declarative manner of > >> today's > >> >> > > > > > > > infrastructure. For example, you tell k8s that you need > >> 10 TMs, and > >> >> > > > > > > you'll > >> >> > > > > > > > eventually get them. > >> >> > > > > > > > - (minus) In the case of large state jobs, the cost of > >> multiple > >> >> > > > > > > rescalings > >> >> > > > > > > > might outweigh the above. > >> >> > > > > > > > > >> >> > > > > > > > We've already touched on the solution to this problem > on > >> the FLIP. > >> >> > > > > > Please > >> >> > > > > > > > notice the parallelism knob being a range with a lower > >> and upper > >> >> > > > > bound. > >> >> > > > > > > > Setting both the lower and upper bound to the same > value > >> could give > >> >> > > > > the > >> >> > > > > > > > behavior you're describing at the cost of giving up > some > >> properties > >> >> > > > > > that > >> >> > > > > > > AS > >> >> > > > > > > > gives you (you'd be falling back to the > >> DefaultScheduler's behavior). > >> >> > > > > > > > > >> >> > > > > > > > when user upgrade job-vertx-parallelism . I want to > have > >> an interface > >> >> > > > > > to > >> >> > > > > > > > > query the current update parallel execution status, > so > >> that the > >> >> > > > > user > >> >> > > > > > or > >> >> > > > > > > > > program can understand the current status > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > This is a misunderstanding. We're not introducing the > >> RESCALE > >> >> > > > > endpoint. > >> >> > > > > > > > This endpoint allows you to re-declare the resources > >> needed to run > >> >> > > > > the > >> >> > > > > > > job. > >> >> > > > > > > > Once you reach the desired resources (you get more > >> resources than the > >> >> > > > > > > lower > >> >> > > > > > > > bound defines), your job will run. > >> >> > > > > > > > > >> >> > > > > > > > We can expose a similar endpoint to "resource > >> requirements" to give > >> >> > > > > you > >> >> > > > > > > an > >> >> > > > > > > > overview of the resources the vertices already have. > You > >> can already > >> >> > > > > > get > >> >> > > > > > > > this from the REST API, so exposing this in yet another > >> way should be > >> >> > > > > > > > considered carefully. > >> >> > > > > > > > > >> >> > > > > > > > *@Matthias* > >> >> > > > > > > > > >> >> > > > > > > > I'm wondering whether it makes sense to add some kind > of > >> resource ID > >> >> > > > > to > >> >> > > > > > > the > >> >> > > > > > > > > REST API. > >> >> > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > That's a good question. I want to think about that and > >> get back to > >> >> > > > > the > >> >> > > > > > > > question later. My main struggle when thinking about > this > >> is, "if > >> >> > > > > this > >> >> > > > > > > > would be an idempotent POST endpoint," would it be any > >> different? > >> >> > > > > > > > > >> >> > > > > > > > How often do we allow resource requirements to be > changed? > >> >> > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > There shall be no rate limiting on the FLINK side. If > >> this is > >> >> > > > > something > >> >> > > > > > > > your environment needs, you can achieve it on a > different > >> layer ("we > >> >> > > > > > > can't > >> >> > > > > > > > have FLINK to do everything"). > >> >> > > > > > > > > >> >> > > > > > > > Versioning the JobGraph in the JobGraphStore rather > than > >> overwriting > >> >> > > > > it > >> >> > > > > > > > > might be an idea. > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > This sounds interesting since it would be closer to the > >> JobGraph > >> >> > > > > being > >> >> > > > > > > > immutable. The main problem I see here is that this > would > >> introduce a > >> >> > > > > > > > BW-incompatible change so it might be a topic for > >> follow-up FLIP. > >> >> > > > > > > > > >> >> > > > > > > > I'm just wondering whether we bundle two things > together > >> that are > >> >> > > > > > > actually > >> >> > > > > > > > > separate > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > Yup, this is how we think about it as well. The main > >> question is, > >> >> > > > > "who > >> >> > > > > > > > should be responsible for bookkeeping 1) the JobGraph > and > >> 2) the > >> >> > > > > > > > JobResourceRequirements". The JobMaster would be the > >> right place for > >> >> > > > > > > both, > >> >> > > > > > > > but it's currently not the case, and we're tightly > >> coupling the > >> >> > > > > > > dispatcher > >> >> > > > > > > > with the JobMaster. > >> >> > > > > > > > > >> >> > > > > > > > Initially, we tried to introduce a separate HA > component > >> in JobMaster > >> >> > > > > > for > >> >> > > > > > > > bookkeeping the JobResourceRequirements, but that > proved > >> to be a more > >> >> > > > > > > > significant effort adding additional mess to the > already > >> messy HA > >> >> > > > > > > > ecosystem. Another approach we've discussed was > mutating > >> the JobGraph > >> >> > > > > > and > >> >> > > > > > > > setting JRR into the JobGraph structure itself. > >> >> > > > > > > > > >> >> > > > > > > > The middle ground for keeping this effort reasonably > >> sized and not > >> >> > > > > > > > violating "we want to keep JG immutable" too much is > >> keeping the > >> >> > > > > > > > JobResourceRequirements separate as an internal config > >> option in > >> >> > > > > > > JobGraph's > >> >> > > > > > > > configuration. > >> >> > > > > > > > > >> >> > > > > > > > We ultimately need to rethink the tight coupling of > >> Dispatcher and > >> >> > > > > > > > JobMaster, but it needs to be a separate effort. > >> >> > > > > > > > > >> >> > > > > > > > ...also considering the amount of data that can be > stored > >> in a > >> >> > > > > > > > > ConfigMap/ZooKeeper node if versioning the resource > >> requirement > >> >> > > > > > change > >> >> > > > > > > as > >> >> > > > > > > > > proposed in my previous item is an option for us. > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > AFAIK we're only storing pointers to the S3 objects in > HA > >> metadata, > >> >> > > > > so > >> >> > > > > > we > >> >> > > > > > > > should be okay with having larger structures for now. > >> >> > > > > > > > > >> >> > > > > > > > Updating the JobGraphStore means adding more requests > to > >> the HA > >> >> > > > > backend > >> >> > > > > > > > API. > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > It's fine unless you intend to override the resource > >> requirements a > >> >> > > > > few > >> >> > > > > > > > times per second. > >> >> > > > > > > > > >> >> > > > > > > > *@Shammon* > >> >> > > > > > > > > >> >> > > > > > > > How about adding some more information such as vertex > type > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > Since it was intended as a "debug" endpoint, it makes > >> complete sense! > >> >> > > > > > > > > >> >> > > > > > > > For sql jobs, we always use a unified parallelism for > >> most vertices. > >> >> > > > > > Can > >> >> > > > > > > > > we provide them with a more convenient setting method > >> instead of > >> >> > > > > each > >> >> > > > > > > > one? > >> >> > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > I completely feel with this. The main thoughts when > >> designing the API > >> >> > > > > > > were: > >> >> > > > > > > > - We want to keep it clean and easy to understand. > >> >> > > > > > > > - Global parallelism can be modeled using per-vertex > >> parallelism but > >> >> > > > > > not > >> >> > > > > > > > the other way around. > >> >> > > > > > > > - The API will be used by external tooling (operator, > >> auto scaler). > >> >> > > > > > > > > >> >> > > > > > > > Can you elaborate more about how you'd intend to use > the > >> endpoint? I > >> >> > > > > > > think > >> >> > > > > > > > we can ultimately introduce a way of re-declaring > >> "per-vertex > >> >> > > > > > defaults," > >> >> > > > > > > > but I'd like to understand the use case bit more first. > >> >> > > > > > > > > >> >> > > > > > > > *@Weijie* > >> >> > > > > > > > > >> >> > > > > > > > What is the default value here (based on what > >> configuration), or just > >> >> > > > > > > > > infinite? > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > Currently, for the lower bound, it's always one, and > for > >> the upper > >> >> > > > > > bound, > >> >> > > > > > > > it's either parallelism (if defined) or the > >> maxParallelism of the > >> >> > > > > > vertex > >> >> > > > > > > in > >> >> > > > > > > > JobGraph. This question might be another signal for > >> making the > >> >> > > > > defaults > >> >> > > > > > > > explicit (see the answer to Shammon's question above). > >> >> > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > Thanks, everyone, for your initial thoughts! > >> >> > > > > > > > > >> >> > > > > > > > Best, > >> >> > > > > > > > D. > >> >> > > > > > > > > >> >> > > > > > > > On Tue, Feb 7, 2023 at 4:39 AM weijie guo < > >> guoweijieres...@gmail.com > >> >> > > > > > > >> >> > > > > > > > wrote: > >> >> > > > > > > > > >> >> > > > > > > > > Thanks David for driving this. This is a very > valuable > >> work, > >> >> > > > > > especially > >> >> > > > > > > > for > >> >> > > > > > > > > cloud native environment. > >> >> > > > > > > > > > >> >> > > > > > > > > >> How about adding some more information such as > >> vertex type > >> >> > > > > > > > > (SOURCE/MAP/JOIN and .etc) in the response of `get > jobs > >> >> > > > > > > > > resource-requirements`? For users, only vertex-id may > >> be difficult > >> >> > > > > to > >> >> > > > > > > > > understand. > >> >> > > > > > > > > > >> >> > > > > > > > > +1 for this suggestion, including jobvertex's name in > >> the response > >> >> > > > > > body > >> >> > > > > > > > is > >> >> > > > > > > > > more > >> >> > > > > > > > > user-friendly. > >> >> > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > > I saw this sentence in FLIP: "Setting the upper bound > >> to -1 will > >> >> > > > > > reset > >> >> > > > > > > > the > >> >> > > > > > > > > value to the default setting." What is the default > >> value here > >> >> > > > > (based > >> >> > > > > > > on > >> >> > > > > > > > > what configuration), or just infinite? > >> >> > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > > Best regards, > >> >> > > > > > > > > > >> >> > > > > > > > > Weijie > >> >> > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > > Shammon FY <zjur...@gmail.com> 于2023年2月6日周一 18:06写道： > >> >> > > > > > > > > > >> >> > > > > > > > > > Hi David > >> >> > > > > > > > > > > >> >> > > > > > > > > > Thanks for initiating this discussion. I think > >> declaring job > >> >> > > > > > resource > >> >> > > > > > > > > > requirements by REST API is very valuable. I just > >> left some > >> >> > > > > > comments > >> >> > > > > > > as > >> >> > > > > > > > > > followed > >> >> > > > > > > > > > > >> >> > > > > > > > > > 1) How about adding some more information such as > >> vertex type > >> >> > > > > > > > > > (SOURCE/MAP/JOIN and .etc) in the response of `get > >> jobs > >> >> > > > > > > > > > resource-requirements`? For users, only vertex-id > may > >> be > >> >> > > > > difficult > >> >> > > > > > to > >> >> > > > > > > > > > understand. > >> >> > > > > > > > > > > >> >> > > > > > > > > > 2) For sql jobs, we always use a unified > parallelism > >> for most > >> >> > > > > > > vertices. > >> >> > > > > > > > > Can > >> >> > > > > > > > > > we provide them with a more convenient setting > method > >> instead of > >> >> > > > > > each > >> >> > > > > > > > > one? > >> >> > > > > > > > > > > >> >> > > > > > > > > > > >> >> > > > > > > > > > Best, > >> >> > > > > > > > > > Shammon > >> >> > > > > > > > > > > >> >> > > > > > > > > > > >> >> > > > > > > > > > On Fri, Feb 3, 2023 at 8:18 PM Matthias Pohl < > >> >> > > > > > matthias.p...@aiven.io > >> >> > > > > > > > > > .invalid> > >> >> > > > > > > > > > wrote: > >> >> > > > > > > > > > > >> >> > > > > > > > > > > Thanks David for creating this FLIP. It sounds > >> promising and > >> >> > > > > > useful > >> >> > > > > > > > to > >> >> > > > > > > > > > > have. Here are some thoughts from my side (some > of > >> them might > >> >> > > > > be > >> >> > > > > > > > > rather a > >> >> > > > > > > > > > > follow-up and not necessarily part of this FLIP): > >> >> > > > > > > > > > > - I'm wondering whether it makes sense to add > some > >> kind of > >> >> > > > > > resource > >> >> > > > > > > > ID > >> >> > > > > > > > > to > >> >> > > > > > > > > > > the REST API. This would give Flink a tool to > >> verify the PATCH > >> >> > > > > > > > request > >> >> > > > > > > > > of > >> >> > > > > > > > > > > the external system in a compare-and-set kind of > >> manner. AFAIU, > >> >> > > > > > the > >> >> > > > > > > > > > process > >> >> > > > > > > > > > > requires the external system to retrieve the > >> resource > >> >> > > > > > requirements > >> >> > > > > > > > > first > >> >> > > > > > > > > > > (to retrieve the vertex IDs). A resource ID <ABC> > >> would be sent > >> >> > > > > > > along > >> >> > > > > > > > > as > >> >> > > > > > > > > > a > >> >> > > > > > > > > > > unique identifier for the provided setup. It's > >> essentially the > >> >> > > > > > > > version > >> >> > > > > > > > > ID > >> >> > > > > > > > > > > of the currently deployed resource requirement > >> configuration. > >> >> > > > > > Flink > >> >> > > > > > > > > > doesn't > >> >> > > > > > > > > > > know whether the external system would use the > >> provided > >> >> > > > > > information > >> >> > > > > > > > in > >> >> > > > > > > > > > some > >> >> > > > > > > > > > > way to derive a new set of resource requirements > >> for this job. > >> >> > > > > > The > >> >> > > > > > > > > > > subsequent PATCH request with updated resource > >> requirements > >> >> > > > > would > >> >> > > > > > > > > include > >> >> > > > > > > > > > > the previously retrieved resource ID <ABC>. The > >> PATCH call > >> >> > > > > would > >> >> > > > > > > fail > >> >> > > > > > > > > if > >> >> > > > > > > > > > > there was a concurrent PATCH call in between > >> indicating to the > >> >> > > > > > > > external > >> >> > > > > > > > > > > system that the resource requirements were > >> concurrently > >> >> > > > > updated. > >> >> > > > > > > > > > > - How often do we allow resource requirements to > be > >> changed? > >> >> > > > > That > >> >> > > > > > > > > > question > >> >> > > > > > > > > > > might make my previous comment on the resource ID > >> obsolete > >> >> > > > > > because > >> >> > > > > > > we > >> >> > > > > > > > > > could > >> >> > > > > > > > > > > just make any PATCH call fail if there was a > >> resource > >> >> > > > > requirement > >> >> > > > > > > > > update > >> >> > > > > > > > > > > within a certain time frame before the request. > But > >> such a time > >> >> > > > > > > > period > >> >> > > > > > > > > is > >> >> > > > > > > > > > > something we might want to make configurable > then, > >> I guess. > >> >> > > > > > > > > > > - Versioning the JobGraph in the JobGraphStore > >> rather than > >> >> > > > > > > > overwriting > >> >> > > > > > > > > it > >> >> > > > > > > > > > > might be an idea. This would enable us to provide > >> resource > >> >> > > > > > > > requirement > >> >> > > > > > > > > > > changes in the UI or through the REST API. It is > >> related to a > >> >> > > > > > > problem > >> >> > > > > > > > > > > around keeping track of the exception history > >> within the > >> >> > > > > > > > > > AdaptiveScheduler > >> >> > > > > > > > > > > and also having to consider multiple versions of > a > >> JobGraph. > >> >> > > > > But > >> >> > > > > > > for > >> >> > > > > > > > > that > >> >> > > > > > > > > > > one, we use the ExecutionGraphInfoStore right > now. > >> >> > > > > > > > > > > - Updating the JobGraph in the JobGraphStore > makes > >> sense. I'm > >> >> > > > > > just > >> >> > > > > > > > > > > wondering whether we bundle two things together > >> that are > >> >> > > > > actually > >> >> > > > > > > > > > separate: > >> >> > > > > > > > > > > The business logic and the execution > configuration > >> (the > >> >> > > > > resource > >> >> > > > > > > > > > > requirements). I'm aware that this is not a flaw > of > >> the current > >> >> > > > > > > FLIP > >> >> > > > > > > > > but > >> >> > > > > > > > > > > rather something that was not necessary to > address > >> in the past > >> >> > > > > > > > because > >> >> > > > > > > > > > the > >> >> > > > > > > > > > > JobGraph was kind of static. I don't remember > >> whether that was > >> >> > > > > > > > already > >> >> > > > > > > > > > > discussed while working on the AdaptiveScheduler > >> for FLIP-160 > >> >> > > > > > [1]. > >> >> > > > > > > > > Maybe, > >> >> > > > > > > > > > > I'm missing some functionality here that requires > >> us to have > >> >> > > > > > > > everything > >> >> > > > > > > > > > in > >> >> > > > > > > > > > > one place. But it feels like updating the entire > >> JobGraph which > >> >> > > > > > > could > >> >> > > > > > > > > be > >> >> > > > > > > > > > > actually a "config change" is not reasonable. > >> ...also > >> >> > > > > considering > >> >> > > > > > > the > >> >> > > > > > > > > > > amount of data that can be stored in a > >> ConfigMap/ZooKeeper node > >> >> > > > > > if > >> >> > > > > > > > > > > versioning the resource requirement change as > >> proposed in my > >> >> > > > > > > previous > >> >> > > > > > > > > > item > >> >> > > > > > > > > > > is an option for us. > >> >> > > > > > > > > > > - Updating the JobGraphStore means adding more > >> requests to the > >> >> > > > > HA > >> >> > > > > > > > > backend > >> >> > > > > > > > > > > API. There were some concerns shared in the > >> discussion thread > >> >> > > > > [2] > >> >> > > > > > > for > >> >> > > > > > > > > > > FLIP-270 [3] on pressuring the k8s API server in > >> the past with > >> >> > > > > > too > >> >> > > > > > > > many > >> >> > > > > > > > > > > calls. Eventhough, it's more likely to be caused > by > >> >> > > > > > checkpointing, > >> >> > > > > > > I > >> >> > > > > > > > > > still > >> >> > > > > > > > > > > wanted to bring it up. We're working on a > >> standardized > >> >> > > > > > performance > >> >> > > > > > > > test > >> >> > > > > > > > > > to > >> >> > > > > > > > > > > prepare going forward with FLIP-270 [3] right > now. > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > Best, > >> >> > > > > > > > > > > Matthias > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > [1] > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > >> >> > > > > > > >> >> > > > > > >> > https://cwiki.apache.org/confluence/display/FLINK/FLIP-160%3A+Adaptive+Scheduler > >> >> > > > > > > > > > > [2] > >> >> > > > > > > > >> https://lists.apache.org/thread/bm6rmxxk6fbrqfsgz71gvso58950d4mj > >> >> > > > > > > > > > > [3] > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > >> >> > > > > > > >> >> > > > > > >> > https://cwiki.apache.org/confluence/display/FLINK/FLIP-270%3A+Repeatable+Cleanup+of+Checkpoints > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > On Fri, Feb 3, 2023 at 10:31 AM ConradJam < > >> jam.gz...@gmail.com > >> >> > > > > > > >> >> > > > > > > > wrote: > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > > Hi David: > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > Thank you for drive this flip, which helps less > >> flink > >> >> > > > > shutdown > >> >> > > > > > > time > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > for this flip, I would like to make a few idea > on > >> share > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > - when the number of "slots" is > insufficient, > >> can we can > >> >> > > > > > stop > >> >> > > > > > > > > users > >> >> > > > > > > > > > > > rescaling or throw something to tell user > >> "less avaliable > >> >> > > > > > > slots > >> >> > > > > > > > to > >> >> > > > > > > > > > > > upgrade, > >> >> > > > > > > > > > > > please checkout your alivalbe slots" ? Or we > >> could have a > >> >> > > > > > > > request > >> >> > > > > > > > > > > > switch(true/false) to allow this behavior > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > - when user upgrade job-vertx-parallelism . > I > >> want to have > >> >> > > > > > an > >> >> > > > > > > > > > > interface > >> >> > > > > > > > > > > > to query the current update parallel > execution > >> status, so > >> >> > > > > > that > >> >> > > > > > > > the > >> >> > > > > > > > > > > user > >> >> > > > > > > > > > > > or > >> >> > > > > > > > > > > > program can understand the current status > >> >> > > > > > > > > > > > - I want to have an interface to query the > >> current update > >> >> > > > > > > > > > parallelism > >> >> > > > > > > > > > > > execution status. This also helps similar to > >> *[1] Flink > >> >> > > > > K8S > >> >> > > > > > > > > > Operator* > >> >> > > > > > > > > > > > management > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > { > >> >> > > > > > > > > > > > status: Failed > >> >> > > > > > > > > > > > reason: "less avaliable slots to upgrade, > >> please checkout > >> >> > > > > > your > >> >> > > > > > > > > > alivalbe > >> >> > > > > > > > > > > > slots" > >> >> > > > > > > > > > > > } > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > - *Pending*: this job now is join the > upgrade > >> queue,it > >> >> > > > > will > >> >> > > > > > be > >> >> > > > > > > > > > update > >> >> > > > > > > > > > > > later > >> >> > > > > > > > > > > > - *Rescaling*: job now is rescaling,wait it > >> finish > >> >> > > > > > > > > > > > - *Finished*: finish do it > >> >> > > > > > > > > > > > - *Failed* : something have wrong,so this > job > >> is not > >> >> > > > > > alivable > >> >> > > > > > > > > > upgrade > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > I want to supplement my above content in flip, > >> what do you > >> >> > > > > > think > >> >> > > > > > > ? > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > 1. > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > >> >> > > > > > >> https://nightlies.apache.org/flink/flink-kubernetes-operator-docs-main/ > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > David Morávek <d...@apache.org> 于2023年2月3日周五 > >> 16:42写道： > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > Hi everyone, > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > This FLIP [1] introduces a new REST API for > >> declaring > >> >> > > > > > resource > >> >> > > > > > > > > > > > requirements > >> >> > > > > > > > > > > > > for the Adaptive Scheduler. There seems to > be a > >> clear need > >> >> > > > > > for > >> >> > > > > > > > this > >> >> > > > > > > > > > API > >> >> > > > > > > > > > > > > based on the discussion on the "Reworking the > >> Rescale API" > >> >> > > > > > [2] > >> >> > > > > > > > > > thread. > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > Before we get started, this work is heavily > >> based on the > >> >> > > > > > > > prototype > >> >> > > > > > > > > > [3] > >> >> > > > > > > > > > > > > created by Till Rohrmann, and the FLIP is > being > >> published > >> >> > > > > > with > >> >> > > > > > > > his > >> >> > > > > > > > > > > > consent. > >> >> > > > > > > > > > > > > Big shoutout to him! > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > Last and not least, thanks to Chesnay and > Roman > >> for the > >> >> > > > > > initial > >> >> > > > > > > > > > reviews > >> >> > > > > > > > > > > > and > >> >> > > > > > > > > > > > > discussions. > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > The best start would be watching a short demo > >> [4] that I've > >> >> > > > > > > > > recorded, > >> >> > > > > > > > > > > > which > >> >> > > > > > > > > > > > > illustrates newly added capabilities > (rescaling > >> the running > >> >> > > > > > > job, > >> >> > > > > > > > > > > handing > >> >> > > > > > > > > > > > > back resources to the RM, and session cluster > >> support). > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > The intuition behind the FLIP is being able > to > >> define > >> >> > > > > > resource > >> >> > > > > > > > > > > > requirements > >> >> > > > > > > > > > > > > ("resource boundaries") externally that the > >> >> > > > > AdaptiveScheduler > >> >> > > > > > > can > >> >> > > > > > > > > > > > navigate > >> >> > > > > > > > > > > > > within. This is a building block for > >> higher-level efforts > >> >> > > > > > such > >> >> > > > > > > as > >> >> > > > > > > > > an > >> >> > > > > > > > > > > > > external Autoscaler. The natural extension of > >> this work > >> >> > > > > would > >> >> > > > > > > be > >> >> > > > > > > > to > >> >> > > > > > > > > > > allow > >> >> > > > > > > > > > > > > to specify per-vertex ResourceProfiles. > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > Looking forward to your thoughts; any > feedback > >> is > >> >> > > > > > appreciated! > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > [1] > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > >> >> > > > > > > >> >> > > > > > >> > https://cwiki.apache.org/confluence/display/FLINK/FLIP-291%3A+Externalized+Declarative+Resource+Management > >> >> > > > > > > > > > > > > [2] > >> >> > > > > > > > > > >> https://lists.apache.org/thread/2f7dgr88xtbmsohtr0f6wmsvw8sw04f5 > >> >> > > > > > > > > > > > > [3] > >> https://github.com/tillrohrmann/flink/tree/autoscaling > >> >> > > > > > > > > > > > > [4] > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > >> https://drive.google.com/file/d/1Vp8W-7Zk_iKXPTAiBT-eLPmCMd_I57Ty/view > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > Best, > >> >> > > > > > > > > > > > > D. > >> >> > > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > -- > >> >> > > > > > > > > > > > Best > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > ConradJam > >> >> > > > > > > > > > > > > >> >> > > > > > > > > > > > >> >> > > > > > > > > > > >> >> > > > > > > > > > >> >> > > > > > > > > >> >> > > > > > > > >> >> > > > > > > >> >> > > > > > >> >
