Cannot start docker under circus

Question

If I run sudo docker start redis, docker starts. But if I run sudo circusd --daemon circus.ini, it doesn't start.

circus.ini

[watcher:redis]
cmd = docker start redis

Answer 1

The docker start command starts a container and then exits, whereas a process supervisor like Circus expects your process to stay in the foreground as long as it is running. You would probably get the behavior you want if you were to add the --attach argument:

cmd = docker start --attach redis

This will cause the client to attach to the redis container rather than exiting immediately.