I have read the docker documentation about restart policy of containers.
However, I failed to understand the difference between on-failure
and unless-stopped
.
When will I use one over the other? In which situations will a certain policy lead to starting a container and the other policy not?
on-failure
will issue a restart if the exit code indicated a failure, whereas unless-stopped
behaves like always
and will keep an instance running unless the container is stopped.
You can try with the hello-world to see the difference.
docker run --restart on-failure hello-world
will run once and exit successfully, and running a subsequent docker ps
will indicate no currently running instances of the container.
However, docker run --restart unless-stopped hello-world
will restart the container even if it successfully exits, so subsequently running docker ps
will show you a restarting instance until you stop the container.
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4d498ebd13a6 hello-world "/hello" 2 seconds ago Restarting (0) Less than a second ago modest_keldysh