Install nsenter and docker-enter on any Ubuntu host

docker-enter

#!/bin/bash

if [[ $EUID -ne 0 ]]; then
  echo "You must be root to execute this script" 2>&1
else
  PID=$(docker inspect --format "{{ .State.Pid }}" "$1")
  nsenter --target $PID --mount --uts --ipc --net --pid
fi

install-nsenter.sh

#!/bin/bash

set -e

curl -o util-linux_2.24-1~1_amd64.deb "http://ppa.launchpad.net/78luphr0rnk2nuqimstywepozxn9kl19tqh0tx66b5dki1xxsh5mkz9gl-launchpad-a811i2i3ytqlsztthjth0svbccw8inm65tmkqp9sarr553jq53in4xm1m/util-linux/ubuntu/pool/main/u/util-linux/util-linux_2.24-1~1_amd64.deb"
sudo dpkg --install --ignore-depends=libblkid1,libmount1,libsmartcols1 --force-overwrite util-linux_2.24-1~1_amd64.deb

sudo curl -o /usr/local/bin/docker-enter https://gist.githubusercontent.com/lox/d210a74d3c2f317786ab/raw/docker-enter 
sudo chmod +x /usr/local/bin/docker-enter

I'm sure ignoring those dependencies is horrible. The alternative was grabbing a deb from a PPA directly.

This turned out to be a terrible idea, instead:

docker run --rm -v /usr/local/bin:/target yungsang/nsinit