Disposable Ansible playground

Neutral Debian-based Docker image running an OpenSSH server with s6. Designed for executing Ansible playbooks in reproducible environments using SSH and non-SSH connection types.

Containers are ideal for running Ansible integration tests because they allow the creation of disposable environments locally without any resource overhead.

Building the image

The USER_SSH_PUBKEY variable must be passed as a build-time variable to Docker:

❯ docker build \
     -t demo/debian-ssh \
     --build-arg USER_SSH_PUBKEY="$(cat ~/.ssh/id_ecdsa.pub)" .

The resulting image starts an sshd instance listening on port 22.

Connecting via SSH

Create a container from that image and connect to the running container via SSH with the ansible user, using the SSH key corresponding to the USER_SSH_PUBKEY variable set at build time:

Linux

The IP address of the container is directly accessible from the local host.

❯ CONTAINER_ID="$(docker run -d demo/debian-ssh)" # eg. df626f91b277
❯ CONTAINER_IPADDR="$(docker container inspect \
    --format '{{ .NetworkSettings.IPAddress }}' "$CONTAINER_ID")" # eg. 172.17.0.2

❯ ssh ansible@"$CONTAINER_IPADDR"

macOS

The IP address of the container is not directly accessible from the local host. One must publish the port 22 of the container to some port on the local host.

❯ CONTAINER_ID="$(docker -d -p 22 run demo/debian-ssh)"  # eg. df626f91b277
❯ CONTAINER_PORT="$(docker container inspect \
    --format '{{ index .NetworkSettings.Ports "22/tcp" 0 "HostPort" }}' "$CONTAINER_ID")" # eg. 32770

❯ ssh ansible@localhost -p"$CONTAINER_PORT"

Integration with an Ansible inventory

Add the local container(s) to your Ansible inventory:

# /etc/ansible/hosts

[localdocker]
# linux
docker1 ansible_host=172.17.0.2
docker2 ansible_host=172.17.0.3
# macos
# docker1 ansible_host=localhost ansible_port=32770
# docker2 ansible_host=localhost ansible_port=32771

[localdocker:vars]
ansible_user=ansible

❯ ansible -a 'cat /etc/os-release' localdocker
docker1 | SUCCESS | rc=0 >>
PRETTY_NAME="Debian GNU/Linux 8 (jessie)"
NAME="Debian GNU/Linux"
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