Attach to docker container via nsenter

docker_attach

#!/bin/bash

USAGE="Attach to Docker Container
--------------------------
Attach to Docker Container even if the container does not run
ssh daemon. This is accomplished by using linux containers
directly via 'nsenter' (see http://bit.ly/docker_nsenter).
To install 'nsenter', just execute:

    $ docker run -v /usr/local/bin:/target jpetazzo/nsenter

Usage: sudo $(basename $0) [-h] [cid]

note:
    nsenter requires root privileges

options:
    -h --help:     Print this help message
    cid:           Docker container ID to attach to.
                   If ID is not given, latest running docker
                   container will be attached to as determined
                   by 'docker ps -l'.
"

CID=

while true; do
    case "$1" in
        -h | --help )
            echo "$USAGE"
            exit 0
            ;;
        -- )
            shift;
            break
            ;;
        * )
            CID=$1;
            shift;
            ;;
    esac
    if [ -z $1 ]; then
        break
    fi
done

# No container ID provided
# get the latest running container ID
if [ -z $CID ]; then
    CID=$(docker ps -l | grep -v CONTAINER | grep -v Exited | awk '{print $1}')
fi

# No container ID so exit
if [ -z $CID ]; then
   echo 'No latest running container'
   exit 1
fi

# attach to container
PID=$(docker inspect --format {{.State.Pid}} $CID)
nsenter --target $PID --mount --uts --ipc --net --pid