How to build docker images using Ansible playbooks. With a brief introduction to docker itself.

1. HELLO WORLD!
Toshio Kuratomi
Worked for Red Hat on the Fedora Infrastructure Team
Little bit of sysadmin work
Gobs of Python

2. FUN WITH CONTAINERS
and
Toshio Kuratomi

3. WHAT IS DOCKER?
Manages Linux containers
Allows deploying applications in isolation
Docker Hub ecosystem for distributing general containers

4. IMAGES
Made of layers
Base Images basically OS installs
Immutable
Customize by creating a new layer on top

5. WHAT CAN I DO WITH IT?
Lightweight cloud
Tool for encapsulating applications

6. LIGHTWEIGHT CLOUD
Lower runtime overhead
Layered filesystem
Very quick startup time

7. ENCAPSULATED APPLICATIONS
Low overhead
Run application on startup
Similar to init

8. GREAT! SO WHAT'S ANSIBLE GOT TO DO WITH IT?

9. BUILDING AN IMAGE (DOCKERFILE)
FROM centos:stable
RUN yum -y upgrade
RUN yum install httpd
COPY httpd.conf /etc/httpd/conf/httpd.conf
EXPOSE 80
ENTRYPOINT ["/usr/sbin/apachectl", "-DFOREGOUND"]

10. BUILDING AN IMAGE (WITH ANSIBLE)
FROM ansible/centos7-ansible:stable
ADD ansible /srv/example/
WORKDIR /srv/example
RUN ansible-playbook site.yml -c local
EXPOSE 80
ENTRYPOINT ["/usr/sbin/apachectl", "-DFOREGROUND"]

11. BUILDING AN IMAGE (WITH ANSIBLE)
ansible/site.yml:
- hosts: localhost
tasks:
- yum: pkg=httpd state=present
- copy:
src: httpd.conf
dest: /etc/httpd/conf/httpd.conf
group: "apache"
mode: "0644"

12. HUH. SO WHAT MAKES ANSIBLE BETTER?
Power and consistency
Same method to configure images as your hosts
Templates and Conditionals
Portability
Try out new things via Galaxy roles

13. A MORE COMPLEX EXAMPLE!
- hosts: localhost
vars:
apache_group:
Debian: "root"
RedHat: "apache"
apache_ctl:
Debian: "/usr/sbin/apache2ctl"
RedHat: "/usr/sbin/apachectl"

14. A MORE COMPLEX EXAMPLE!
tasks:
- yum: pkg=httpd state=present
when: ansible_os_family == "RedHat"
- apt: update_cache=yes name="apache2" state=present
when: ansible_os_family == "Debian"
- name: Make an apachectl symlink that is the same between distros
file:
state: link
src: "{{apache_ctl[ansible_os_family]}}"
dest: /usr/local/bin/apachectl

15. A MORE COMPLEX EXAMPLE!
- name: Apply httpd configuration from template
template:
src: httpd.conf.j2
dest: /etc/httpd/conf/httpd.conf
group: "{{ apache_group[ansible_os_family] }}"
mode: "0644"

16. GALAXY + DOCKER == TRY BEFORE YOU BUY
FROM ansible/ubuntu14.04-ansible:stable
RUN mkdir /srv/example
WORKDIR /srv/example
ADD site.yml /srv/example/
RUN ansible-galaxy install geerlingguy.memcached
RUN ansible-playbook site.yml -c local
EXPOSE 11211
ENTRYPOINT ["/usr/bin/memcached", "-u", "memcache", "-l", "0.0.0.0", "-c" "1024", "-p",

17. GALAXY + DOCKER == TRY BEFORE YOU BUY
- hosts: localhost
roles:
- role: geerlingguy.memcached

18. IMAGES FOR BUILDING
Ansible layered on a Base OS Image
Building four images
Two images for Ubuntu-14.04
Two images for CentOS-7
An image for Ansible HEAD
An image for the Ansible release on pypi

19. CONTACT INFO & RESOURCES
https://registry.hub.docker.com/u/ansible/centos7-ansible/
https://registry.hub.docker.com/u/ansible/ubuntu14.04-ansible/
http://ansible.github.com/ansible/ansible-docker-base
http://ansible.com
tkuratomi@ansible.com