ah, did not know that. Thanks for letting me know. The image is not that important, all the important information is in the gist: https://gist.github.com/pingzh/cc44c97336560b658d012c225a2242cc#file-jobdispatcherexecutor-py
Best wishes Ping Zhang On Sun, Aug 23, 2020 at 11:59 PM Deng Xiaodong <xd.den...@gmail.com> wrote: > Hi Ping, > > Inserting images in the email body doesn’t work for this mail list. So we > cannot actually see the pictures you shared. > > If you find them important, you may share the pictures somewhere then > provide the links in the mail body. > > Thanks. > > XD > > On Mon, Aug 24, 2020 at 08:56 Ping Zhang <pin...@umich.edu> wrote: > > > Great ideas. > > > > Actually, when I evaluated using KubernetesExecutor in Airbnb, I created > > *JobDispatcherExecutor*, which is similar to the idea 2. > > > > We have tons of sensor tasks launched at around UTC 00:00 and we enabled > > the SmartSensor, which means each sensor task is very short running. If > we > > choose to have one pod per task, the k8s cluster will not be able to > handle > > the bursty load. > > > > Thus, I created a JobDispatcherExecutor which takes an instance of > > `celery_executor` and `kubernetes_executor`. > > [image: image.png] > > And there is a router > > < > https://gist.github.com/pingzh/cc44c97336560b658d012c225a2242cc#file-jobdispatcherexecutor-py-L165-L168 > > > > method to determine use which executor to queue_command, > > [image: image.png] > > It is currently based on whether a task is a smart sensor task, but it > can > > be easily changed to other attributes and/or settings.policy (so that > infra > > can have control). > > > > Here is the gist: > > > https://gist.github.com/pingzh/cc44c97336560b658d012c225a2242cc#file-jobdispatcherexecutor-py > > > > [image: image.png] > > > > > > Would love to get some feedback. > > > > Best wishes > > > > Ping Zhang > > > > > > On Thu, Aug 13, 2020 at 12:58 PM Jarek Potiuk <jarek.pot...@polidea.com> > > wrote: > > > >> +1 for pod mutation in config. It's not a "yamly" thing - it's a python > >> > >> > >> code to run, so it's quite appropriate to have it in config. > >> > >> > >> > >> > >> > >> On Wed, Aug 12, 2020 at 9:43 PM Daniel Imberman < > >> daniel.imber...@gmail.com> > >> > >> > >> wrote: > >> > >> > >> > >> > >> > >> > I think pod_mutation is important as an “admin override”. E.g. there > >> might > >> > >> > >> > be a label that is required by security policy for all tasks launched > by > >> > >> > >> > airflow. I do agree that the executor_config should take in a V1Pod > >> object > >> > >> > >> > > >> > >> > >> > One option is that the executor_config could take in a > pod_mutation_hook > >> > >> > >> > function as well? So users can manually override the pod functionally > >> > >> > >> > rather than just giving an object and hoping it merges the way they > >> expect > >> > >> > >> > it to? > >> > >> > >> > via Newton Mail [ > >> > >> > >> > > >> > https://cloudmagic.com/k/d/mailapp?ct=dx&cv=10.0.50&pv=10.15.5&source=email_footer_2 > >> > >> > >> > ] > >> > >> > >> > On Wed, Aug 12, 2020 at 12:19 PM, David Lum <davidlu...@gmail.com> > >> wrote: > >> > >> > >> > I'll just leave some passing thoughts here. How the pod template file > is > >> > >> > >> > modified by the executor config might not be very well defined. > >> Currently > >> > >> > >> > when a user passes in a k8s.V1Pod object through executor_config we > >> kind of > >> > >> > >> > arbitrarily merge the two pod definitions to what we imagine the > client > >> > >> > >> > would want, but it could be often misinterpreted. Previously the > >> > >> > >> > Airflow-defined Pod class was fairly flat. This made merging the two > >> > >> > >> > objects fairly straight forward. If the user wrote the field in > >> > >> > >> > executor_config, it overwrote that field in the Pod definition, but > the > >> > >> > >> > rest stayed the same. When attributes are arbitrarily nested like in > the > >> > >> > >> > k8s.V1Pod, some aspects can be mistakenly overwritten. For example, > >> > >> > >> > specifying the volumeMounts of a container requires also specifying > the > >> > >> > >> > rest of the V1Pod. How do we handle this? Do we just overwrite > >> > >> > >> > volumeMounts? The client must have specified a container, so do we > >> > >> > >> > overwrite that too? The fact that there is a choice means the API > could > >> be > >> > >> > >> > unintuitive to the user. > >> > >> > >> > > >> > >> > >> > What I suggest might be easier is that executor_config completely > >> replaces > >> > >> > >> > the pod_template_file if it is specified, but then also offer > something > >> > >> > >> > like pod_mutation_hook at the operator level. This makes it quite > clear > >> to > >> > >> > >> > the user, you are either replacing the pod_template, or you are > >> modifying > >> > >> > >> > the pod_template with pod_mutation_hook and you are doing it by your > own > >> > >> > >> > rules. the argument to executor_config can be something like > >> > >> > >> > ``` > >> > >> > >> > executor_config: { 'KubernetesExector': {'pod_mutation': some_func, > >> > >> > >> > 'pod_template': k8s.V1Pod(...) }} # Pod template could also be a path > >> to a > >> > >> > >> > file > >> > >> > >> > ``` > >> > >> > >> > > >> > >> > >> > If both are specified then pod_mutation is a function applied to > >> > >> > >> > pod_template. Thoughts? > >> > >> > >> > > >> > >> > >> > On Wed, Aug 12, 2020 at 11:24 AM Tomasz Urbaszek < > turbas...@apache.org> > >> > >> > >> > wrote: > >> > >> > >> > > >> > >> > >> > > +1 for the idea, thanks Daniel! I agree that multi-executor and pod > >> > >> > >> > > templates should be 2.1. > >> > >> > >> > > > >> > >> > >> > > T. > >> > >> > >> > > > >> > >> > >> > > On Wed, Aug 12, 2020 at 5:13 PM Daniel Imberman < > >> > >> > >> > daniel.imber...@gmail.com> > >> > >> > >> > > wrote: > >> > >> > >> > > > >> > >> > >> > >> (Also funny enough we could use a lot of the existing > infrastructure > >> int > >> > >> > >> > >> 1.10 to create that migration script. Would just need to take the > >> python > >> > >> > >> > >> dictionary and use the python yaml library) > >> > >> > >> > >> > >> > >> > >> > >> via Newton Mail [ > >> > >> > >> > >> > >> > >> > >> > > >> > https://cloudmagic.com/k/d/mailapp?ct=dx&cv=10.0.50&pv=10.15.5&source=email_footer_2 > >> > >> > >> > >> ] > >> > >> > >> > >> On Wed, Aug 12, 2020 at 8:09 AM, Daniel Imberman < > >> > >> > >> > >> daniel.imber...@gmail.com> wrote: > >> > >> > >> > >> 100% agreed on timing. I think 2.0 should be for the breaking > aspect > >> > >> > >> > >> (losing the configurations) and then 2.1/2.2 we can start adding on > >> the > >> > >> > >> > new > >> > >> > >> > >> features. I also like the idea of a migration tool. We can make a > >> script > >> > >> > >> > >> that takes your airflow.cfg and converts that into a yaml file. > >> > >> > >> > >> > >> > >> > >> > >> via Newton Mail [ > >> > >> > >> > >> > >> > >> > >> > > >> > https://cloudmagic.com/k/d/mailapp?ct=dx&cv=10.0.50&pv=10.15.5&source=email_footer_2 > >> > >> > >> > >> ] > >> > >> > >> > >> On Wed, Aug 12, 2020 at 7:48 AM, Jarek Potiuk < > >> jarek.pot...@polidea.com > >> > >> > >> > > > >> > >> > >> > >> wrote: > >> > >> > >> > >> Big +1. All the arguments are very appealing to me and simplifying > >> the > >> > >> > >> > >> Kubernetes Executor down to YAML-configurable one seems like a > >> > >> > >> > no-brainer > >> > >> > >> > >> especially if we provide some migration tools. I've lost countless > >> hours > >> > >> > >> > >> on > >> > >> > >> > >> debugging some configuration problems, simply because the relevant > >> > >> > >> > >> Kubernetes-related configuration was in the least expected place - > >> i.e. > >> > >> > >> > >> airflow.cfg. YAML configuration. > >> > >> > >> > >> > >> > >> > >> > >> I am also a big fan of both 1. and 2. I've implemented a POC of > >> > >> > >> > >> queue-based multi-scheduler once but having it embedded as part of > >> core > >> > >> > >> > >> Airflow rather than based it on queues (which are basically a > Celery > >> > >> > >> > >> Executor concept) is I think much better approach. Both 1. and 2. > are > >> > >> > >> > >> cool. > >> > >> > >> > >> > >> > >> > >> > >> Now - question about timing. If we decide to go that route - my > view > >> is > >> > >> > >> > >> that simplifying Kubernetes should be an Airflow 2.0 task - > alongside > >> > >> > >> > more > >> > >> > >> > >> comprehensive tests (which will be much easier to write in this > >> case). > >> > >> > >> > The > >> > >> > >> > >> new features/ideas 1. 2. for KE I think should come after that - > >> when we > >> > >> > >> > >> release and stabilize 2.0. Sounds like great candidates for 2.1 to > >> me. > >> > >> > >> > >> > >> > >> > >> > >> J. > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> On Wed, Aug 12, 2020 at 4:24 PM Daniel Imberman < > >> > >> > >> > >> daniel.imber...@gmail.com> > >> > >> > >> > >> wrote: > >> > >> > >> > >> > >> > >> > >> > >> > Hello, fellow Airflowers! I hope you are all well in these trying > >> > >> > >> > times. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > With the recent launch of Airflow 2.0 preparation, it now seems > >> like a > >> > >> > >> > >> > good time to review the project's state and where we can fit in > >> some > >> > >> > >> > >> > breaking changes that will improve the project for the future. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > When we first created the KubernetesExecutor, we had two goals in > >> > >> > >> > mind. > >> > >> > >> > >> > The first goal was to improve the airflow Auto scaling story. > >> > >> > >> > >> Previously, > >> > >> > >> > >> > airflow users would have to manually provision celery workers, > >> which > >> > >> > >> > >> could > >> > >> > >> > >> > lead to wasted resources or missed SLAs. The other goal was to > >> > >> > >> > >> introduce a > >> > >> > >> > >> > community that was not yet well versed in the Kubernetes API to > the > >> > >> > >> > >> > Kubernetes system. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > To ease the community's transition, we abstracted many of the > >> > >> > >> > >> complexities > >> > >> > >> > >> > of creating a Kubernetes object. We chose to offer a limited > >> number of > >> > >> > >> > >> > configurations and keep much of the pod creation process internal > >> to > >> > >> > >> > >> > airflow. In the short-term, this system lowered the barrier to > >> entry. > >> > >> > >> > >> Over > >> > >> > >> > >> > time, however, this abstraction has become a nightmare of tech > >> debt as > >> > >> > >> > >> the > >> > >> > >> > >> > Kubernetes API is expensive and constantly changing. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > With this in mind, I think it's time for us to consider a more > >> > >> > >> > >> > straightforward approach that takes the complexity out of Airflow > >> and > >> > >> > >> > >> > offers the full Kubernetes API to the airflow user. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > What I'm proposing here is pretty straightforward. We remove all > >> > >> > >> > >> > Kubernetes pod creation configurations from the airflow.cfg and > >> > >> > >> > instead > >> > >> > >> > >> > offer only one way to use the KubernetesExecutor: with a YAML > file. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > We can easily supply all of the configurations to the > >> > >> > >> > KubernetesExecutor > >> > >> > >> > >> > by offering example YAMLs (git sync mode is just a sidecar and an > >> init > >> > >> > >> > >> > container, DAG volumes are just an example volume and volume > mount, > >> > >> > >> > >> etc.). > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > This system would simplify a user's ability to predict what a pod > >> will > >> > >> > >> > >> > look like once it is launched by airflow. They will know it's a > >> base > >> > >> > >> > pod > >> > >> > >> > >> > and will be able to simply modify the pod object using the > executor > >> > >> > >> > >> config > >> > >> > >> > >> > and the pod mutation hook. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > This simplification could also lead to some pretty great new > >> features > >> > >> > >> > in > >> > >> > >> > >> > the KubernetesExecutor > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > Idea 1: Picking a pod_template_file per-task > >> > >> > >> > >> > Along with the existing customization with the executor config, > >> solely > >> > >> > >> > >> > relying on pod files can allow users to pick the pod template > file > >> > >> > >> > that > >> > >> > >> > >> > they want to use as their base pod on a per-task basis. An > Airflow > >> > >> > >> > >> engineer > >> > >> > >> > >> > could supply several pre-made templates for their data scientists > >> to > >> > >> > >> > >> reduce > >> > >> > >> > >> > the amount of customization an airflow user would need to use. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > Idea 2: Merging the KubernetesExecutor into the CeleryExecutor > >> > >> > >> > >> > One idea that we've been excited about recently has been the idea > >> of > >> > >> > >> > >> > creating merged Celery and Kubernetes executor. This hybrid > >> executor > >> > >> > >> > >> would > >> > >> > >> > >> > default to launching celery workers with KEDA and would have the > >> > >> > >> > option > >> > >> > >> > >> to > >> > >> > >> > >> > launch individual tasks using the Kubernetes executor when a user > >> > >> > >> > wants > >> > >> > >> > >> > isolation or customization. Simplifying the Kubernetes executor > >> > >> > >> > reduces > >> > >> > >> > >> the > >> > >> > >> > >> > number of fail-points that this merged executor would need to > >> account > >> > >> > >> > >> for. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > What would we need to do to implement this? > >> > >> > >> > >> > The good news here is that the hard work has already been done! > As > >> of > >> > >> > >> > >> > AIRFLOW-5413 [https://issues.apache.org/jira/browse/AIRFLOW-5413 > ] > >> by > >> > >> > >> > >> > David Lum, airflow already has the ability to use base worker > pods > >> on > >> > >> > >> > a > >> > >> > >> > >> > template file. This would involve primarily code deletion and > very > >> > >> > >> > >> little > >> > >> > >> > >> > new code. > >> > >> > >> > >> > > >> > >> > >> > >> > > >> > >> > >> > >> > Thank you for your time and I look forward to the community’s > >> > >> > >> > >> discussion. > >> > >> > >> > >> > > >> > >> > >> > >> > Daniel > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> -- > >> > >> > >> > >> > >> > >> > >> > >> Jarek Potiuk > >> > >> > >> > >> Polidea <https://www.polidea.com/> | Principal Software Engineer > >> > >> > >> > >> > >> > >> > >> > >> M: +48 660 796 129 <+48660796129> > >> > >> > >> > >> [image: Polidea] <https://www.polidea.com/> > >> > >> > >> > > > >> > >> > >> > > > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> -- > >> > >> > >> > >> > >> > >> Jarek Potiuk > >> > >> > >> Polidea <https://www.polidea.com/> | Principal Software Engineer > >> > >> > >> > >> > >> > >> M: +48 660 796 129 <+48660796129> > >> > >> > >> [image: Polidea] <https://www.polidea.com/> > >> > >> > >> > > > > >
