I have a docker container with apache running in foreground. On stopping the docker container , a SIGTERM is sent to all the child processes , which is apache in our case.
Now, the problem i am facing is to gracefully shutdown apache on receiving SIGTERM signal.
Apache normally terminates on the current requests immediately which is the main cause of the problem . Somehow, i need to translate the SIGTERM signal to SIGWINCH , which would eventually gracefully shutdown the server.
I was thinking of writing some kind of wrapper script , but couldn't get as to how to start.
Any suggestions in this regard would be highly appreciated!
Thanks.
The tomcat inside of container can be stopped gracefully by issuing below command (change tomcat path if needed):
docker exec -it <container id / name> /usr/local/apache2/bin/apachectl -k graceful
And to your comment, if you want to see the tomcat log in case if it is not running in foreground
docker exec -it <container id / name> tail -f tail -f /usr/local/apache2/logs/error_log
UPDATE: Based on the comments.
From the docker documentation, you may specify the time while stopping the docker container. By default, it will only wait for 10 sec.
To stop container with different timeout:
docker stop -t <time in seconds> <container id/ name>
I believe that, increasing time out while stopping might help in your case.
UPDATE2 sending custom signal, SIGWINCH in your case. Please refer here for more details.
docker kill -s SIGWINCH <apache container id / name>
UPDATE3
There are helpful resources on signal trapping:
https://medium.com/@gchudnov/trapping-signals-in-docker-containers-7a57fdda7d86#.qp68kskwd
http://www.techbar.me/stopping-docker-containers-gracefully/
Hope these are helpful.
