The guardian state runs the Docker container

More often than not, you need to have the Docker container run as a daemonized in the background. At this point, you can -d parameter.

For example, the following command runs the container in the background.

$ sudo docker run -d ubuntu:14.04 /bin/sh -c "while true; do echo hello world; sleep 1; done"
1e5535038e285177d5214659a068137486f96ee5c2e85a4ac52dc83f2ebe4147

Once the container starts, a unique id is returned, or the container information can be viewed through the docker ps command.

$ sudo docker ps
CONTAINER ID  IMAGE         COMMAND               CREATED        STATUS       PORTS NAMES
1e5535038e28  ubuntu:14.04  /bin/sh -c 'while tr  2 minutes ago  Up 1 minute        insane_babbage

To get the output of the container, you can docker logs command.

$ sudo docker logs insane_babbage
hello world
hello world
hello world
. . .