Docker isn't a silver bullet and may not be the best choice for all environments (I'm also looking at potentially launching SDK workers in a different way), but AFAIK there has not been any alternative proposal for default SDK execution that can handle all of Python, Go and Java.
Regardless of the default implementation, we should strive to keep the implementation modular so users can plug in their own replacement as needed. Looking at the prototype implementation, Docker comes downstream of FlinkExecutableStageFunction, and it will be possible to supply a custom implementation by making the translator pluggable (which I intend to work on once backporting to master is complete), and possibly "SDKHarnessManager" itself can also be swapped out. I would also prefer that for Flink and other Java based runners we retain the option to inline executable stages that are in Java. I would expect a good number of use cases to benefit from direct execution in the task manager, and it may be good to offer the user that optimization. Thanks, Thomas On Sat, May 5, 2018 at 12:54 PM, Eugene Kirpichov <kirpic...@google.com> wrote: > To add on that: Romain, if you are really excited about Graal as a > project, here are some constructive suggestions as to what you can do on a > reasonably short timeframe: > - Propose/prototype a design for writing UDFs in Beam SQL using Graal > - Go through the portability-related design documents, come up with a more > precise assessment of what parts are actually dependent on Docker's > container format and/or on Docker itself, and propose a plan for untangling > this dependency and opening the door to other mechanisms of cross-language > execution > > On Sat, May 5, 2018 at 12:50 PM Eugene Kirpichov <kirpic...@google.com> > wrote: > >> Graal is a very young project, currently nowhere near the level of >> maturity or completeness as to be sufficient for Beam to fully bet its >> portability vision on it: >> - Graal currently only claims to support Java and Javascript, with Ruby >> and R in the status of "some applications may run", Python support "just >> beginning", and Go lacking altogether. >> - Regarding existing production usage, the Graal FAQ says it is "a >> project with new innovative technology in its early stages." >> >> That said, as Graal matures, I think it would be reasonable to keep an >> eye on it as a potential future lightweight alternative to containers for >> pipelines where Graal's level of support is sufficient for this particular >> pipeline. >> >> Please also keep in mind that execution of user code is only a small part >> of the overall portability picture, and dependency on Docker is an even >> smaller part of that (there is only 1 mention of the word "Docker" in all >> of Beam's portability protos, and the mention is in an out-of-date TODO >> comment). I hope this addresses your concerns. >> >> On Sat, May 5, 2018 at 11:49 AM Romain Manni-Bucau <rmannibu...@gmail.com> >> wrote: >> >>> Agree >>> >>> The jvm is still mainstream for big data and it is trivial to have a >>> remote facade to support natives but no point to have it in runners, it is >>> some particular transforms or even dofn and sources only... >>> >>> >>> Le 5 mai 2018 19:03, "Andrew Pilloud" <apill...@google.com> a écrit : >>> >>>> Thanks for the examples earlier, I think Hazelcast is a great example >>>> of something portability might make more difficult. I'm not working on >>>> portability, but my understanding is that the data sent to the runner is a >>>> blob of code and the name of the container to run it in. A runner with a >>>> native language (java on Hazelcast for example) could run the code directly >>>> without the container if it is in a language it supports. So when Hazelcast >>>> sees a known java container specified, it just loads the java blob and runs >>>> it. When it sees another container it rejects the pipeline. You could use >>>> Graal in the Hazelcast runner to do this for a number of languages. I would >>>> expect that this could also be done in the direct runner, which similarly >>>> provides a native java environment, so portable Java pipelines can be >>>> tested without docker? >>>> >>>> For another way to frame this: if Beam was originally written in Go, we >>>> would be having a different discussion. A pipeline written entirely in java >>>> wouldn't be possible, so instead to enable Hazelcast, we would have to be >>>> able to run the java from portability without running the container. >>>> >>>> Andrew >>>> >>>> On Sat, May 5, 2018 at 1:48 AM Romain Manni-Bucau < >>>> rmannibu...@gmail.com> wrote: >>>> >>>>> >>>>> >>>>> 2018-05-05 9:27 GMT+02:00 Ismaël Mejía <ieme...@gmail.com>: >>>>> >>>>>> Graal would not be a viable solution for the reasons Henning and >>>>>> Andrew >>>>>> mentioned, or put in other words, when users choose a programming >>>>>> language >>>>>> they don’t choose only a ‘friendly’ syntax or programming model, they >>>>>> choose also the ecosystem that comes with it, and the libraries that >>>>>> make >>>>>> their life easier. However isolating these user >>>>>> libraries/dependencies is a >>>>>> hard problem and so far the standard solution to this problem is to >>>>>> use >>>>>> operating systems containers via docker. >>>>>> >>>>> >>>>> Graal solves that Ismael. Same kind of experience than running npm >>>>> libs on nashorn but with a more unified API to run any language soft. >>>>> >>>>> >>>>>> >>>>>> The Beam vision from day zero is to run pipelines written in multiple >>>>>> languages in runners in multiple systems, and so far we are not doing >>>>>> this >>>>>> in particular in the Apache runners. The portability work is the >>>>>> cleanest >>>>>> way to achieve this vision given the constraints. >>>>>> >>>>> >>>>> Hmm, did I read it wrong and we don't have specific integration of the >>>>> portable API in runners? This is what is messing up the runners and >>>>> limiting beam adoption on existing runners. >>>>> Portable API is a feature buildable on top of runner, not in runners. >>>>> Same as a runner implementing the 5-6 primitives can run anything, the >>>>> portable API should just rely on that and not require more integration. >>>>> It doesn't prevent more deep integrations as for some higher level >>>>> primitives existing in runners but it is not the case today for runners so >>>>> shouldn't exist IMHO. >>>>> >>>>> >>>>>> >>>>>> I agree however that for the Java SDK to Java runner case this can >>>>>> represent additional pain, docker ideally should not be a requirement >>>>>> for >>>>>> Java users with the Direct runner and debugging a pipeline should be >>>>>> as >>>>>> easy as it is today. I think the Univerrsal Local Runner exists to >>>>>> cover >>>>>> the Portable case, but after looking at this JIRA I am not sure if >>>>>> unification is coming (and by consequence if docker would be >>>>>> mandatory). >>>>>> https://issues.apache.org/jira/browse/BEAM-4239 >>>>>> >>>>>> I suppose for the distributed runners that they must implement the >>>>>> full >>>>>> Portability APIs to be considered Beam multi language compliant but >>>>>> they >>>>>> can prefer for performance reasons to translate without the >>>>>> portability >>>>>> APIs the Java to Java case. >>>>>> >>>>> >>>>> >>>>> This is my issue, language portability must NOT impact runners at all, >>>>> it is just a way to forward primitives to a runner. >>>>> See it as a layer rewriting the pipeline and submitting it. No need to >>>>> modify any runner. >>>>> >>>>> >>>>>> On Sat, May 5, 2018 at 9:11 AM Reuven Lax <re...@google.com> wrote: >>>>>> >>>>>> > A beam cluster with the spark runner would include a spark cluster, >>>>>> plus >>>>>> what's needed for portability, plus the beam sdk. >>>>>> >>>>>> > On Fri, May 4, 2018, 11:55 PM Romain Manni-Bucau < >>>>>> rmannibu...@gmail.com> >>>>>> wrote: >>>>>> >>>>>> >>>>>> >>>>>> >> Le 5 mai 2018 08:43, "Reuven Lax" <re...@google.com> a écrit : >>>>>> >>>>>> >> I don't believe we enforce docker anywhere. In fact if someone >>>>>> wanted to >>>>>> run an all-windows beam cluster, they would probably not use docker >>>>>> for >>>>>> their runner (docker runs on Windows, but not efficiently). >>>>>> >>>>>> >>>>>> >>>>>> >> Or doesnt run sometimes - a colleague hit that yesterday :(. >>>>>> >>>>>> >> What is a "beam cluster" - opposed to a spark or foink cluster? How >>>>>> would it work on windows servers? >>>>>> >>>>>> >>>>>> >> On Fri, May 4, 2018, 11:19 PM Romain Manni-Bucau < >>>>>> rmannibu...@gmail.com> >>>>>> wrote: >>>>>> >>>>>> >>>>>> >>>>>> >>> 2018-05-05 2:33 GMT+02:00 Andrew Pilloud <apill...@google.com>: >>>>>> >>>>>> >>>> What docker really buys is a package format and runtime >>>>>> environment >>>>>> that is language and operating system agnostic. The docker packaging >>>>>> and >>>>>> runtime format is the de facto standard for portable applications >>>>>> such as >>>>>> this, and there is a group trying to turn it into an actual standard. >>>>>> >>>>>> >>>> I would agree with you that dockerd has become bloated but there >>>>>> are >>>>>> projects that solve that. There is no longer lock-in to dockerd, >>>>>> there are >>>>>> package format compatible docker replacements that eliminate the >>>>>> performance issues and overhead associated with docker. CRI-O ( >>>>>> https://github.com/kubernetes-incubator/cri-o) is a really cool >>>>>> RedHat >>>>>> project which is a minimalist replacement for docker. I was recently >>>>>> working at a startup where I migrated our "data mover" appliance from >>>>>> Docker to CRI-O. Our application was able to get direct access to the >>>>>> ethernet driver and block devices which enabled a huge performance >>>>>> boost >>>>>> but we were also able to run containers produced by docker without >>>>>> modification. >>>>>> >>>>>> >>>> You mention that docker is "detail of one runner+vendor >>>>>> corrupting all >>>>>> the project and adding complexity and work to everyone". It sounds >>>>>> like you >>>>>> have a specific example you'd like to share? Is there a runner that is >>>>>> unable to move to portability because of docker? >>>>>> >>>>>> >>>>>> >>> IBM one for instance, some custom ones like an hazelcast based >>>>>> one, >>>>>> etc... More generally any runner developped outside beam itself - >>>>>> even if >>>>>> we take a snapshot today, most of beam's ones have the same pitall. >>>>>> >>>>>> >>> Note: i never said docker was a bad techno or so. Let me try to >>>>>> clarify. >>>>>> >>>>>> >>> Main issue is that you enforce docker usage which is still >>>>>> trendy. It >>>>>> is like scla which was promishing to kill java, check what it does >>>>>> today... >>>>>> >>> It starts to be tooled but it is also very impacting on the >>>>>> deployment >>>>>> side and for a good number of beam users who deploy it outside the >>>>>> cloud it >>>>>> is an issue. >>>>>> >>> Keep in mind beam is embeddable by design, it is not a runner >>>>>> environment and with the docker choice it imposes some environment >>>>>> which is >>>>>> inconsistent with beam design itself and this is where this choice >>>>>> blocks. >>>>>> >>>>>> >>>>>> >>>>>> >>>> Andrew >>>>>> >>>>>> >>>> On Fri, May 4, 2018 at 4:32 PM Henning Rohde <hero...@google.com >>>>>> > >>>>>> wrote: >>>>>> >>>>>> >>>>> Romain, >>>>>> >>>>>> >>>>> Docker, unlike selinux, solves a great number of tangible >>>>>> problems >>>>>> for us with IMO a relatively small tax. It does not have to be the >>>>>> only >>>>>> way. Some of the concerns you bring up along with possibilities were >>>>>> also >>>>>> discussed here: https://s.apache.org/beam-fn-api-container-contract. >>>>>> I >>>>>> encourage you to take a look. >>>>>> >>>>>> >>>>> Thanks, >>>>>> >>>>> Henning >>>>>> >>>>>> >>>>>> >>>>> On Fri, May 4, 2018 at 3:18 PM Romain Manni-Bucau < >>>>>> rmannibu...@gmail.com> wrote: >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> Le 4 mai 2018 21:31, "Henning Rohde" <hero...@google.com> a >>>>>> écrit : >>>>>> >>>>>> >>>>>> I disagree with the characterization of docker and the >>>>>> implications >>>>>> made towards portability. Graal looks like a neat project (and I never >>>>>> thought I would live to see the phrase "Practical Partial Evaluation" >>>>>> ..), >>>>>> but it doesn't address the needs of portability. In addition to Luke's >>>>>> examples, Go and most other languages don't work on it either. Docker >>>>>> containers also address packaging, OS dependencies, conflicting >>>>>> versions >>>>>> and distribution aspects in addition to truly universal language >>>>>> support. >>>>>> >>>>>> >>>>>> >>>>>> This is wrong, docker also has its conflicts, is not universal >>>>>> (fails on windows and mac easily - as host or not, cloud vendors put >>>>>> layers >>>>>> limiting or corrupting it, and it is an infra constraint imposed and a >>>>>> vendor locking not welcomed in beam IMHO). >>>>>> >>>>>> >>>>>> This is my main concern. All the work done looks like an >>>>>> implemzntation detail of one runner+vendor corrupting all the project >>>>>> and >>>>>> adding complexity and work to everyone instead of keeping it localised >>>>>> (technically it is possible). >>>>>> >>>>>> >>>>>> Would you accept i enforce you to use selinux? Using docker is >>>>>> the >>>>>> same kind of constraint. >>>>>> >>>>>> >>>>>> >>>>>> That said, it's entirely fine for some runners to use Jython, >>>>>> Graal, >>>>>> etc to provide a specialized offering similar to the direct runners, >>>>>> but it >>>>>> would be disjoint from portability IMO. >>>>>> >>>>>> >>>>>> On Fri, May 4, 2018 at 10:14 AM Romain Manni-Bucau < >>>>>> rmannibu...@gmail.com> wrote: >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> Le 4 mai 2018 17:55, "Lukasz Cwik" <lc...@google.com> a >>>>>> écrit : >>>>>> >>>>>> >>>>>>> I did take a look at Graal a while back when thinking about >>>>>> how >>>>>> execution environments could be defined, my concerns were related to >>>>>> it not >>>>>> supporting all of the features of a language. >>>>>> >>>>>>> For example, its typical for Python to load and call native >>>>>> libraries and Graal can only execute C/C++ code that has been >>>>>> compiled to >>>>>> LLVM. >>>>>> >>>>>>> Also, a good amount of people interested in using ML >>>>>> libraries will >>>>>> want access to GPUs to improve performance which I believe that Graal >>>>>> can't >>>>>> support. >>>>>> >>>>>> >>>>>>> It can be a very useful way to run simple lamda functions >>>>>> written >>>>>> in some language directly without needing to use a docker environment >>>>>> but >>>>>> you could probably use something even lighter weight then Graal that >>>>>> is >>>>>> language specific like Jython. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> Right, the jsr223 impl works very well but you can also have >>>>>> a perf >>>>>> boost using native (like v8 java binding for js for instance). It is >>>>>> way >>>>>> more efficient than docker most of the time and not code intrusive at >>>>>> all >>>>>> in runners so likely more adoption-able and maintainable. That said >>>>>> all is >>>>>> doable behind the jsr223 so maybe not a big deal in terms of api. We >>>>>> just >>>>>> need to ensure portability work stay clean and actually portable and >>>>>> doesnt >>>>>> impact runners as poc done until today did. >>>>>> >>>>>> >>>>>>> Works for me. >>>>>> >>>>>> >>>>>> >>>>>>> On Thu, May 3, 2018 at 10:05 PM Romain Manni-Bucau < >>>>>> rmannibu...@gmail.com> wrote: >>>>>> >>>>>> >>>>>>>> Hi guys >>>>>> >>>>>> >>>>>>>> Since some time there are efforts to have a language portable >>>>>> support in beam but I cant really find a case it "works" being based >>>>>> on >>>>>> docker except for some vendor specific infra. >>>>>> >>>>>> >>>>>>>> Current solution: >>>>>> >>>>>> >>>>>>>> 1. Is runner intrusive (which is bad for beam and prevents >>>>>> adoption of big data vendors) >>>>>> >>>>>>>> 2. Based on docker (which assumed a runtime environment and >>>>>> is >>>>>> very ops/infra intrusive and likely too $$ quite often for what it >>>>>> brings) >>>>>> >>>>>> >>>>>>>> Did anyone had a look to graal which seems a way to make the >>>>>> feature doable in a lighter manner and optimized compared to default >>>>>> jsr223 >>>>>> impls? >>>>>> >>>>> >>>>>
