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If it's such a straightforward fix, why isn't it part of the docker core? I'd love to hear from the docker team why it's not a concern for them. Presumably if i

by lox 11y ago

If it's such a straightforward fix, why isn't it part of the docker core? I'd love to hear from the docker team why it's not a concern for them. Presumably if it was they'd have addressed it by now. From my own experience with docker in production, I'm yet to see any of the described scenarios crop up. Has anyone else, or is this solving an extreme edge case?

ckuehl 11y ago
> From my own experience with docker in production, I'm yet to see any of the described scenarios crop up. Has anyone else, or is this solving an extreme edge case? The biggest issue we see at Yelp is leaking containers in test (e.g. Jenkins aborting a job but leaving the containers it spawned still running). Depending on how you orchestrate containers, you might not encounter the issue in prod. If you're using something like Kubernates or Marathon or Paasta, they're probably going to do the "right thing" and ensure the containers are actually stopped. We also use containers a lot in development. For example, we might put a single tool into a container, and then when developers call that tool, they're actually spawning a container without realizing it. For this use case, it's really important that signals are handled properly so that Ctrl-C (and similar) continues working.
- sandGorgon 11y ago
  Why did you not use something like supervisord? I run a few containers (obviously not at yelp scale) and supervisors has been spectacular at restarting, managing,reloading,etc. It handles nginx,gunicorn,puma,tomcat, etc pretty well. Yes its python - but was that the motivation? Also,you guys should comment on https://github.com/docker/docker/pull/5773 https://github.com/docker/docker/pull/5773 which is work on unprivileged systemd in docker. I think you guys can influence the bug with your experience in this.
  - anonbanker 11y ago
    some of us don't want systemd and it's tag-alongs ruining our docker.
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zenlikethat 11y ago
Zombies are not uncommon to see for an app running in a container that forks off other processes. This isn't every program but forking processes is pretty common, enough so to be worrisome. For instance, some programs watch the Docker event stream and can reload, say, HAproxy configuration to automatically load balance any new containers which come up. In my experience, running such a program in a container can make reloading the HAproxy process frequently tend to create a huge variety of zombie processes - and once they're present, zombies are difficult to eliminate without a reboot.

by lox 11y ago

ckuehl 11y ago

> From my own experience with docker in production, I'm yet to see any of the described scenarios crop up. Has anyone else, or is this solving an extreme edge case? The biggest issue we see at Yelp is leaking containers in test (e.g. Jenkins aborting a job but leaving the containers it spawned still running). Depending on how you orchestrate containers, you might not encounter the issue in prod. If you're using something like Kubernates or Marathon or Paasta, they're probably going to do the "right thing" and ensure the containers are actually stopped. We also use containers a lot in development. For example, we might put a single tool into a container, and then when developers call that tool, they're actually spawning a container without realizing it. For this use case, it's really important that signals are handled properly so that Ctrl-C (and similar) continues working.

sandGorgon 11y ago
Why did you not use something like supervisord? I run a few containers (obviously not at yelp scale) and supervisors has been spectacular at restarting, managing,reloading,etc. It handles nginx,gunicorn,puma,tomcat, etc pretty well. Yes its python - but was that the motivation? Also,you guys should comment on https://github.com/docker/docker/pull/5773 https://github.com/docker/docker/pull/5773 which is work on unprivileged systemd in docker. I think you guys can influence the bug with your experience in this.
- anonbanker 11y ago
  some of us don't want systemd and it's tag-alongs ruining our docker.
- deleted 11y ago
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- deleted 11y ago
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zenlikethat 11y ago

Zombies are not uncommon to see for an app running in a container that forks off other processes. This isn't every program but forking processes is pretty common, enough so to be worrisome. For instance, some programs watch the Docker event stream and can reload, say, HAproxy configuration to automatically load balance any new containers which come up. In my experience, running such a program in a container can make reloading the HAproxy process frequently tend to create a huge variety of zombie processes - and once they're present, zombies are difficult to eliminate without a reboot.