Docker: get a shell on the host

docker-shell-on-host.md

$ docker run --privileged --pid=host -it alpine:3.8 \
nsenter -t 1 -m -u -n -i sh

• --rm : removes the container after it is stopped
• -ti (or -t -i) : adds a tty and leaves the standard input opened
• --privileged : grants additional permissions to the container, it allows the container to gain access to the devices of the host (/dev)
• --pid=host : use the host's Process ID Namespace. Allows the container to use the process tree of the Docker host (the machine in which the Docker daemon is running)

nsenter

• -t PID Target process to get namespaces from
• -m Enter mount namespace
• -u Enter UTS namespace (hostname etc)
• -i Enter System V IPC namespace
• -n Enter network namespace
• -p Enter pid namespace