Restart policies

Using the –restart flag on Docker run you can specify a restart policy for how a container should or should not be restarted on exit.

When a restart policy is active on a container, it will be shown as either Up or Restarting in docker ps. It can also be useful to use docker events to see the restart policy in effect.

docker run --always 

Always restart the container regardless of the exit status. When you
specify always, the Docker daemon will try to restart the container
indefinitely. The container will also always start on daemon startup,
regardless of the current state of the container.

I recommend you this documentation about restart-policies

Documentation – Restart policies

Update Docker v19.03

Restart policies (–restart)

Use Docker’s –restart to specify a container’s restart policy. A restart policy > controls whether the Docker daemon restarts a container after exit. Docker supports the following restart policies:

always Always restart the container regardless of the exit status. When you specify always, the Docker daemon will try to restart the container indefinitely. The container will also always start on daemon startup, regardless of the current state of the container.

$ docker run --restart=always redis

Documentation – Restart policies