vagrant with docker backend

Dockerfile

FROM ubuntu:12.04

# https://www.vagrantup.com/docs/boxes/base.html

RUN apt-get update \
&& DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
  bash \
  openssh-server \
  sudo \
&& rm -rf /var/lib/apt/lists/* \
# Required to not get a 'Missing privilege separation directory' error, normally created by init script
&& mkdir /var/run/sshd \
&& chmod 0755 /var/run/sshd

# https://raw.githubusercontent.com/mitchellh/vagrant/master/keys/vagrant.pub /home/vagrant/.ssh/authorized_keys
RUN ssh_key='ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA6NF8iallvQVp22WDkTkyrtvp9eWW6A8YVr+kz4TjGYe7gHzIw+niNltGEFHzD8+v1I2YJ6oXevct1YeS0o9HZyN1Q9qgCgzUFtdOKLv6IedplqoPkcmF0aYet2PkEDo3MlTBckFXPITAMzF8dJSIFo9D8HfdOV0IAdx4O7PtixWKn5y2hMNG0zQPyUecp4pzC6kivAIhyfHilFR61RGL+GPXQ2MWZWFYbAGjyiYJnAmCP3NOTd0jMZEnDkbUvxhMmBYSdETk1rRgm+R4LOzFUGaHqHDLKLX+FIPKcF96hrucXzcWyLbIbEgE98OHlnVYCzRdK8jlqm8tehUc9c9WhQ== vagrant insecure public key' \
# user accounts + passwords
&& useradd --home-dir /home/vagrant --create-home --shell /bin/bash vagrant \
&& mkdir /home/vagrant/.ssh \
&& echo "$ssh_key" > /home/vagrant/.ssh/authorized_keys \
&& echo 'vagrant:vagrant' | chpasswd \
&& echo 'root:vagrant' | chpasswd \
# vagrant wants sudo without password
&& echo 'vagrant ALL=(ALL) NOPASSWD: ALL' > /etc/sudoers.d/vagrant \
# safe enough permissions so sudo/ssh don't complain
&& chmod 0440 /etc/sudoers.d/vagrant \
&& chmod 0700 /home/vagrant/.ssh \
&& chmod 0600 /home/vagrant/.ssh/authorized_keys \
&& chown -R vagrant:vagrant /home/vagrant

EXPOSE 22
CMD ["/usr/sbin/sshd", "-D", "-oUseDNS=no"]

# puppet is optional
RUN apt-get update \
&& DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
  puppet \
&& rm -rf /var/lib/apt/lists/*

Vagrantfile

Vagrant.configure("2") do |config|
  config.vm.provider "docker" do |d, override|
    # https://www.vagrantup.com/docs/docker/configuration.html
    d.build_dir = "."
    d.force_host_vm = false  # since we have Docker for Mac nowadays
    d.has_ssh = true

    # https://github.com/mitchellh/vagrant/issues/7651
    override.ssh.host = "127.0.0.1"
    override.ssh.port = 2222
  end
end