Reputation: 143
I am just starting with docker and I have a silly question. When you list all the containers, you'll see an output like this:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4c01db0b339c ubuntu:12.04 bash 17 seconds ago Up 16 seconds 3300-3310/tcp webapp
d7886598dbe2 crosbymichael/redis:latest /redis-server --dir 33 minutes ago Up 33 minutes 6379/tcp redis,webapp/db
I am wondering what does the COMMAND here signifies? Does it mean the last command run by the container or the first one or something else?
I tried the official docker documentation but couldn't find my answer. Any help?
Upvotes: 1
Views: 126
Reputation: 5037
COMMAND
is the command executed by the container by default when it's started.
When a container is started, a main command is executed, and the container will live until that command finishs. That CMD will be PID 1 inside the container.
In a Dockerfile
you specify that command by CMD
instruction.
Also, I recommend you to take a look to this thread to be aware of the difference between CMD
and ENTRYPOINT
: What is the difference between CMD and ENTRYPOINT in a Dockerfile?
Upvotes: 4