A more reliable way to detect Ubuntu

[nishidayuya]

lsb_release command is included in lsb-release package. Sometimes this is not installed; ex: Docker official Ubuntu image.

$ docker run --rm -it ubuntu:precise bash -l -c 'lsb_release -i'
bash: lsb_release: command not found
$ docker run --rm -it ubuntu:trusty bash -l -c 'lsb_release -i' 
Distributor ID: Ubuntu
$ docker run --rm -it ubuntu:xenial bash -l -c 'lsb_release -i'
bash: lsb_release: command not found

/etc/os-release is included in base-files package, so this is more reliable than lsb_release.

$ docker run --rm -it ubuntu:precise bash -l -c '. /etc/os-release && echo $ID'  
ubuntu
$ docker run --rm -it ubuntu:trusty bash -l -c '. /etc/os-release && echo $ID' 
ubuntu
$ docker run --rm -it ubuntu:xenial bash -l -c '. /etc/os-release && echo $ID'
ubuntu

This pull-request uses /etc/os-release for Ubuntu detection.

[sethvargo]

I'll need to test this across multiple ubuntu versions

[nishidayuya]

We can try following:

Setup

Requires Vagrant repository and Docker.

Creates following Vagrantfile.

# -*- mode: ruby -*-
# vi: set ft=ruby :

Vagrant.configure(2) do |config|
  config.vm.provider(:docker) do |d|
    d.image = "test_ubuntu"
    d.has_ssh = true
  end
end

Download Dockerfile via wget or curl.

• Ubuntu Xenial: https://raw.githubusercontent.com/nishidayuya/docker-vagrant-ubuntu/d5d296694da65af1440b007f7761392736286cdb/Dockerfile
• Ubuntu Trusty: https://raw.githubusercontent.com/nishidayuya/docker-vagrant-ubuntu/106882046ca45b189c167e1599c2236422c8844b/Dockerfile
  • This version is no problem.
  • Because official ubuntu:trusty image contains lsb-release package (so it is fat image 😭 ).
• Ubuntu Precise: https://raw.githubusercontent.com/nishidayuya/docker-vagrant-ubuntu/8b444efb2815205de153d5cd2682c1d5d12cca1f/Dockerfile

Creates Docker image for Vagrant.

$ docker build -t test_ubuntu .

Before pull-request

Vagrant cannot detect Ubuntu (except Ubuntu Trusty).

$ bundle exec vagrant destroy -f
$ bundle exec vagrant up --provider=docker --debug 2> /tmp/before.log
$ sed -n -e '/^DEBUG guest: Trying: ubuntu/, /^DEBUG ssh: Exit status: / p' \
    /tmp/before.log
DEBUG guest: Trying: ubuntu
DEBUG ssh: Re-using SSH connection.
 INFO ssh: Execute: [ -x /usr/bin/lsb_release ] && /usr/bin/lsb_release -i 2>/dev/null | grep Ubuntu (sudo=false)
DEBUG ssh: Exit status: 1

After pull-request

Vagrant can detect Ubuntu.

$ bundle exec vagrant destroy -f
$ bundle exec vagrant up --provider=docker --debug 2> /tmp/after.log
$ sed -n -e '/^DEBUG guest: Trying: ubuntu/, /^DEBUG ssh: Exit status: / p' \
    /tmp/after.log
DEBUG guest: Trying: ubuntu
DEBUG ssh: Re-using SSH connection.
 INFO ssh: Execute: test -r /etc/os-release && . /etc/os-release && test xubuntu = x$ID (sudo=false)
DEBUG ssh: Exit status: 0

[nishidayuya]

Thank you!

And I tried to use https://raw.githubusercontent.com/nishidayuya/docker-vagrant-ubuntu/d5d296694da65af1440b007f7761392736286cdb/Dockerfile on vagrant_1.8.5_x86_64.deb.
I'll create more smaller Docker image for Vagrant Docker Provider.