Ansible connection plugin using ssh + lxc-attach

This plugin allows to use Ansible on a remote server hosting LXC containers, without having to install SSH servers in each LXC container.

The plugin connects to the host using SSH, then uses lxc or lxc-attach to enter the container.

For LXC version 1 this means the SSH connection must login as root, otherwise lxc-attach will fail.

For LXC version 2 this means that the user must either login as root or must be in the lxc group in order to execute the lxc command.

Add to ansible.cfg:

[defaults]
connection_plugins = /path/to/connection_plugins/lxc_ssh

Then, modify your hosts file to use the lxc_ssh transport:

container ansible_host=server ansible_connection=lxc_ssh ansible_ssh_extra_args=container

This is a fork from the original plugin:

ansible-lxc-ssh by Pierre Chifflier

This fork incorporates a few PRs from the original version, which (April 2017) were never applied. It also works with LXC version 1 (using lxc-*) and LXC version 2 (just using a single lxc binary). The version is autodetected on runtime.

The following is an extract from a Playbook which creates a container. First the hosts.cfg:

[containers]
web ansible_host=physical.host ansible_ssh_extra_args=web

The Playbook:

# deploy the container
- hosts: containers
  become: yes
  # the container is not up, nothing to gather here
  gather_facts: False
  # files on the host system are changed,
  # creating multiple containers in parallel might cause a race condition
  serial: 1

  tasks:
  - name: Create LXD Container
    become: True
    lxd_container:
      name: "{{ inventory_name }}"
      state: started
      source:
        type: image
        mode: pull
        server: https://cloud-images.ubuntu.com/releases
        protocol: simplestreams
        alias: 16.10/amd64
      profiles: ['default']
      wait_for_ipv4_addresses: true
      timeout: 600
    register: container_setup
    delegate_to: "{{ ansible_host }}"
    #delegate_facts: True

The actual container creation is redirected to the ansible_host, also fact gathering is turned off because the container is not yet live. It might be a good idea to create the containers one by one, hence the serialization. In my case I also setup ssh access and hostname resolution during the container setup - this does not work well when run in parallel for multiple containers.

• I haven't found any proper method to access the 'inventory_name' from the connection plugin, so I used 'ansible_ssh_extra_args' to store the name of the container.