Docker Cookbook

"builders"
:
[
{
"type"
:
"docker"
,
"image"
:
"ansible/ubuntu14.04-ansible:stable"
,
"commit"
:
"true"
}
],
"provisioners"
:
[
{
"type"
:
"ansible-local"
,
"playbook_file"
:
"local.yml"
}
],
"post-processors"
:
[
{
"type"
:
"docker-tag"
,
"repository"
:
"how2dock/packer"
,
"tag"
:
"ansible"
2.8 Using Packer to Create a Docker Image | 53

---

}
]
}
It uses a special Docker image, pulled from Docker Hub, that has Ansible installed in
it. Packer will use the local Ansible CLI to run the Ansible playbook 
local.yml
. The
playbook defined in the template file installs Nginx locally:
---
- hosts: localhost
connection: local
tasks:
- name: install nginx
apt: pkg=nginx state=installed update_cache=true
The result of building with Packer will be a working Docker image 
how2dock/
packer:ansible
$ /home/vagrant/packer build template-ansible.json
...
==> docker: Creating a temporary directory for sharing data...
==> docker: Pulling Docker image: ansible/ubuntu14.04-ansible:stable
docker: Pulling repository ansible/ubuntu14.04-ansible
...
==> docker: Provisioning with Ansible...
docker: Creating Ansible staging directory...
docker: Creating directory: /tmp/packer-provisioner-ansible-local
docker: Uploading main Playbook file...
...
docker:
docker: PLAY [localhost] **************************************
docker:
docker: GATHERING FACTS ***************************************
docker: ok: [localhost]
docker:
docker: TASK: [install nginx] *********************************
docker: changed: [localhost]
docker:
docker: PLAY RECAP ********************************************
docker: localhost : ok=2 changed=1 unreachable=0 failed=0
docker:
==> docker: Committing the container
..
docker (docker-tag): Repository: how2dock/packer:ansible
Build 'docker' finished.
A new image is now available, 
how2dock/packer:ansible
, that was built using an Ansi‐
ble playbook. You can start a container based on this image and launch the applica‐
tion as you did before. This interesting workflow allows you to keep the benefit of
your configuration management recipes/playbooks while starting to use containers
instead of virtual machines.