The only question left would be what will be the default value? Cheers, Till
On Tue, Oct 20, 2020 at 10:16 AM Yu Li <car...@gmail.com> wrote: > 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 > > > >>> > > > > > > > > >
