Thanks for clarifying, that was not clear to me. That sounds fine to me, given that it just adds extra information, not changes existing one.
On Wed, May 6, 2020 at 9:06 AM Till Rohrmann <trohrm...@apache.org> wrote: > Just for clarifications and as Yang already pointed out: The discussion > here is about also creating the log, out and err files as well as keeping > writing to STDOUT and STDERR. > > Hence, there should be no regression for K8s users. The main problem, as > Chesnay pointed out, could be the increased disk usage by creating these > files. > > Cheers, > Till > > On Wed, May 6, 2020 at 5:10 AM Yang Wang <danrtsey...@gmail.com> wrote: > > > Hi Thomas Weise, > > > > I am not sure why this change will break the existing K8s/container-based > > setup. > > Since it will output the logs to stdout and log files at the same time, > you > > could still > > use the `kubectl logs` to view the logs. And log collection could just > work > > as before. > > > > What we could benefit from this is the logs could also be accessed via > > Flink web > > dashboard. I think it is more convenient when the users do not have the > > permissions > > to execute `kubectl`. > > > > > > @Till Rohrmann <trohrm...@apache.org>, it will be great if we could use > > tee > > to side output logs to file and avoid > > duplication. I will have a look. > > > > > > Best, > > Yang > > > > Thomas Weise <t...@apache.org> 于2020年5月6日周三 上午1:40写道： > > > > > The downside of change to the default behavior is the breakage of > > existing > > > k8s or other container-based production setups. > > > > > > Logs that are emitted to stdout are visible through kubectl logs and > > > infrastructure is setup for log collection. > > > > > > Thanks, > > > Thomas > > > > > > > > > On Tue, May 5, 2020 at 6:31 AM Arvid Heise <ar...@ververica.com> > wrote: > > > > > > > From my previous experience with K8s, I'd assume that the cluster > > itself > > > > already has some ELK attached to it and all stdout/err is collected > > > > automatically. > > > > > > > > So if you want to also add logs, I'd make that configurable and I'm > > torn > > > > what the default should be as both make sense. > > > > > > > > However, thinking a bit further, it sounds as if the current way is > > > already > > > > very inconsistent. We should probably either have log files for > > > everything > > > > or log everything to stdout/err and let K8s deal with it. And then we > > > > should have some configuration to toggle between the modes. > > > > > > > > On Tue, May 5, 2020 at 2:50 PM Stephan Ewen <se...@apache.org> > wrote: > > > > > > > > > @Patrick could you chime in? > > > > > > > > > > We should at least understand the original motivation before simply > > > > > changing the way it works. > > > > > > > > > > On Tue, May 5, 2020 at 2:49 PM Stephan Ewen <se...@apache.org> > > wrote: > > > > > > > > > > > I think Patrick originally introduced the foreground mode, and I > > > > believe > > > > > > it had indeed something to do with container use and logging. > > > > > > > > > > > > IIRC the default assumption in docker and Kubernetes is that the > > logs > > > > > come > > > > > > on stdout (or stderr) so after "principle of least astonishment" > > the > > > > idea > > > > > > was to give a similar experience with Flink. > > > > > > > > > > > > On Tue, May 5, 2020 at 10:49 AM David Anderson < > > > da...@alpinegizmo.com> > > > > > > wrote: > > > > > > > > > > > >> I like this idea because it should improve the experience (and > > > reduce > > > > > >> confusion) for folks having their first flink experience via one > > of > > > > the > > > > > >> docker playgrounds. Right now it gives the impression that > > something > > > > is > > > > > >> broken out-of-the-box. > > > > > >> > > > > > >> Regards, > > > > > >> David > > > > > >> > > > > > >> On Mon, May 4, 2020 at 6:01 PM Till Rohrmann < > > trohrm...@apache.org> > > > > > >> wrote: > > > > > >> > > > > > >> > Hi everyone, > > > > > >> > > > > > > >> > thanks for starting this discussion Chesnay. > > > > > >> > > > > > > >> > I think it would be nice if we also displayed the logs when > > > starting > > > > > the > > > > > >> > process in the foreground. > > > > > >> > > > > > > >> > The repercussions could be mitigated if the default logger > > > > > >> configurations > > > > > >> > would contain file rolling with a max log file size. > > > > > >> > > > > > > >> > @Yang I think there are solutions how to redirect stdout and > > > stderr > > > > > into > > > > > >> > separate files using tee without duplication [1]. > > > > > >> > > > > > > >> > [1] http://www.softpanorama.org/Tools/tee.shtml > > > > > >> > > > > > > >> > Cheers, > > > > > >> > Till > > > > > >> > > > > > > >> > On Wed, Apr 29, 2020 at 4:28 AM Yang Wang < > > danrtsey...@gmail.com> > > > > > >> wrote: > > > > > >> > > > > > > >> > > Thanks for Chesnay starting this discussion. > > > > > >> > > > > > > > >> > > In FLINK-17166 implementation[1], we are trying to use "tee" > > > > instead > > > > > >> of > > > > > >> > > introducing the stream redirection(redirect the out/err to > > > files). > > > > > >> > However, > > > > > >> > > a side effect is that the logging will be duplicated both in > > > .log > > > > > and > > > > > >> > .out > > > > > >> > > files. > > > > > >> > > Then it may consume more disk space. However it is not a > very > > > > > critical > > > > > >> > > problem since we could use log4j/logback configuration to > > > control > > > > > the > > > > > >> > > rolling > > > > > >> > > files and max size. > > > > > >> > > > > > > > >> > > Also, it only happens in docker/K8s deployment. For > YARN/Mesos > > > > > >> > deployment, > > > > > >> > > the behavior is just same as before. > > > > > >> > > > > > > > >> > > > > > > > >> > > [1]. https://github.com/apache/flink/pull/11839 > > > > > >> > > > > > > > >> > > Best, > > > > > >> > > Yang > > > > > >> > > > > > > > >> > > Chesnay Schepler <ches...@apache.org> 于2020年4月29日周三 > > 上午12:30写道： > > > > > >> > > > > > > > >> > > > Currently, processes started in the foreground (like in > the > > > case > > > > > of > > > > > >> > > > Docker) output all logging/stdout directly to the console, > > > > without > > > > > >> > > > creating any logging files. > > > > > >> > > > > > > > > >> > > > The downside of this approach, as outlined in FLIP-111, is > > > that > > > > > the > > > > > >> > > > WebUI is not able to display the logs since it relies on > > these > > > > > very > > > > > >> > > > files to exist. > > > > > >> > > > > > > > > >> > > > In FLINK-17166 (part of FLIP-111) we are trying to change > > this > > > > > such > > > > > >> > that > > > > > >> > > > we always created .log/.out files. It seems like a > > reasonable > > > > > >> change to > > > > > >> > > > do, but it could have repercussions on existing > deployments > > > > since > > > > > we > > > > > >> > > > will naturally use more disk space (logs gotta go > > somewhere). > > > > > >> > > > > > > > > >> > > > I'm curious what people think about this. > > > > > >> > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > Arvid Heise | Senior Java Developer > > > > > > > > <https://www.ververica.com/> > > > > > > > > Follow us @VervericaData > > > > > > > > -- > > > > > > > > Join Flink Forward <https://flink-forward.org/> - The Apache Flink > > > > Conference > > > > > > > > Stream Processing | Event Driven | Real Time > > > > > > > > -- > > > > > > > > Ververica GmbH | Invalidenstrasse 115, 10115 Berlin, Germany > > > > > > > > -- > > > > Ververica GmbH > > > > Registered at Amtsgericht Charlottenburg: HRB 158244 B > > > > Managing Directors: Timothy Alexander Steinert, Yip Park Tung Jason, > Ji > > > > (Toni) Cheng > > > > > > > > > >
