When restarting containers, part of them can not handle the process properly. like when running `docker restart neutron_server`, you will get following warning:
Aug 18 08:26:07 aio dockerd[914]: time="2016-08-18T08:26:07.968485357-04:00" level=info msg="Container f614cdfad6a47b3a4821074da17d072408a6223f9fbd21016e6fa891a1dbaf48 failed to exit within 10 seconds of signal 15 - using the force"
Aug 18 08:26:08 aio dockerd[914]: time="2016-08-18T08:26:08.037156889-04:00" level=warning msg="libcontainerd: container f614cdfad6a47b3a4821074da17d072408a6223f9fbd21016e6fa891a1dbaf48 restart canceled"
it takes 10 seconds to stop the neutron_server with failed and send a 15 signal to the main process, which is bad.
The root cause is: The Linux kernel applies special signal handling to processes which run as PID 1. the solution is use the dumb-init as the init process in the container. more info please check: https://github.com/Yelp/dumb-init#why-you-need-an-init-system
Reviewed: https:/
Committed: https:/
Submitter: Jenkins
Branch: master
commit 6710bbeb7c8bdce
Author: Jeffrey Zhang <jeffrey.
Date: Thu Aug 18 16:42:02 2016 +0800
Use dumb-init to manage the pid 1 process
Normally, when you launch a Docker container, the process you're
executing becomes PID 1, giving it the quirks and responsibilities that
come with being the init system for the container.
There are two common issues this presents:
* In most cases, signals won't be handled properly.
* Orphaned zombie processes aren't properly reaped.
the dumb-init acting like a simple init system. It launches a single
process and then proxies all received signals to a session rooted at
that child process.
Closes-Bug: #1614509
Change-Id: I9d3d04648e151d