DevOps: Puppet, Docker, and Kubernetes

Injecting a new process to a running container

While doing development and debugging, we might want to look inside the already running container. There are a few utilities, such as nsenter (https://github.com/jpetazzo/nsenter), that allow us to enter into the namespace of the container to inspect it. With the exec option, which was added in Docker 1.3, we can inject a new process inside a running container.

Getting ready

Make sure the Docker daemon is running on the host and you can connect through the Docker client. You might also need a running container to inject a process in.

How to do it…

1. You can inject a process inside a running container with the following command:

    $ docker exec [-d|--detach[=false]] [--help] [-i|--interactive[=false]] [-t|--tty[=false]] ...