I'm also +1 on making it configurable in the same Docker image. It seems we have reached consensus and there are already enough +1s to move forward, and suggest @Yun to conclude the discussion directly if there are no objections.
Thanks. Best Regards, Yu On Fri, 16 Oct 2020 at 23:16, Till Rohrmann <trohrm...@apache.org> wrote: > +1 for making it configurable in the same Docker image. > > Cheers, > Till > > On Fri, Oct 16, 2020 at 12:56 PM Chesnay Schepler <ches...@apache.org> > wrote: > > > If it is possible to support both allocators in a single image then we > > should definitely go with that option. > > > > On 10/16/2020 12:21 PM, Yun Tang wrote: > > > Thanks for Yang's suggestion. I think this could be a better choice. > > > We could install jemalloc and only enable it in LD_PRELOAD when user > > pass specific configuration for docker-entrypoint.sh. > > > By doing so, we could avoid to create another docker image tags and > also > > offer ability to reduce memory fragmentation problem. > > > > > > Does anyone else have other ideas? > > > > > > Best > > > Yun Tang > > > ________________________________ > > > From: Yang Wang <danrtsey...@gmail.com> > > > Sent: Thursday, October 15, 2020 14:59 > > > To: dev <dev@flink.apache.org> > > > Subject: Re: [DISCUSS][docker] Adopt Jemalloc as default memory > > allocator for debian based Flink docker image > > > > > > Thanks Yun Tang for starting this discussion. > > > > > > I think this is very important when deploy Flink with container > > environment > > > in production. I just > > > have quick question. Could we have both memory allocator(e.g. glibc, > > > jemalloc) in the Flink > > > official image and enable a specific one by setting ENV? > > > > > > Best, > > > Yang > > > > > > Yu Li <car...@gmail.com> 于2020年10月14日周三 下午12:23写道： > > > > > >> Thanks for debugging and resolving the issue and driving the > discussion > > >> Yun! > > >> > > >> For the given solutions, I prefer option 1 (supply another Dockerfile > > using > > >> jemalloc as default memory allocator) because of the below reasons: > > >> > > >> 1. It's hard to say jemalloc is always better than ptmalloc (glibc > > malloc), > > >> or else glibc should have already adopted it as the default memory > > >> allocator. And as indicated here [1], in some cases jemalloc will > > >> consume as much as twice the memory than glibc > > >> > > >> 2. All existing Flink docker images use glibc, if we change the > default > > >> memory allocator to jemalloc and only supply one series of images, we > > will > > >> leave those having better performance with glibc no other choices but > > >> staying with old images. In another word, there's a risk of > introducing > > new > > >> problems while fixing an existing one if choosing option-2. > > >> > > >> And there is a third option considering the efforts of maintaining > more > > >> images if the memory leak issue is not widely observed, that we could > > >> document the steps of building Dockerfile with jemalloc as default > > >> allocator so users could build it when needed, which leaves the burden > > to > > >> our users so for me it's not the best option. > > >> > > >> Best Regards, > > >> Yu > > >> > > >> [1] https://stackoverflow.com/a/33993215 > > >> > > >> On Tue, 13 Oct 2020 at 15:34, Yun Tang <myas...@live.com> wrote: > > >> > > >>> Hi all > > >>> > > >>> Users report they meet serious memory leak when submitting jobs > > >>> continously in session mode within k8s (please refer to > FLINK-18712[1] > > ), > > >>> and I also reproduce this to find this is caused by memory > > fragmentation > > >> of > > >>> glibc [2][3] and provide solutions to fix this: > > >>> > > >>> * Quick but not very clean solution to limit the memory pool of > > >> glibc, > > >>> limit MALLOC_ARENA_MAX to 2 > > >>> > > >>> * More general solution by rebuilding the image to install > > >>> libjemalloc-dev and add the libjemalloc.so it to LD_PRELOAD > > >>> > > >>> The reporter adopted the 2nd solution to fix this issue eventually. > > Thus, > > >>> I begin to think whether we should change our Dockerfile to adopt > > >> jemalloc > > >>> as default memory allocator [4]. > > >>> From my point of view, we have two choices: > > >>> > > >>> 1. Introduce another Dockerfile using jemalloc as default memory > > >>> allocator, which means Flink needs another two new image tags to > build > > >>> docker with jemalloc while default docker still use glibc. > > >>> 2. Set the default memory allocator as jemalloc in our existing > > >>> Dockerfiles, which means Flink offer docker image with jemalloc by > > >> default. > > >>> I prefer the 2nd option as our company already use jemalloc as > default > > >>> memory allocator for JDK at our production environment due to > messages > > >> from > > >>> os team warning of glibc's memory fragmentation. > > >>> Moreover, I found several open source projects adopting jemalloc as > > >>> default memory allocator within their images to resolve memory > > >>> fragmentation problem, e.g fluent [5], home-assistant [6]. > > >>> > > >>> What do you guys think of this issue? > > >>> > > >>> [1] https://issues.apache.org/jira/browse/FLINK-18712 > > >>> [2] > > >>> > > >> > > > https://www.gnu.org/software/libc/manual/html_mono/libc.html#Freeing-after-Malloc > > >>> [3] https://sourceware.org/bugzilla/show_bug.cgi?id=15321 > > >>> [4] https://issues.apache.org/jira/browse/FLINK-19125 > > >>> [5] > > >>> > > >> > > > https://docs.fluentbit.io/manual/v/1.0/installation/docker#why-there-is-no-fluent-bit-docker-image-based-on-alpine-linux > > >>> [6] https://github.com/home-assistant/core/pull/33237 > > >>> > > >>> > > >>> Best > > >>> Yun Tang > > >>> > > > > >
