Background on DataCentred, its use of OpenStack and Ceph, a proposed workflow for building Docker images with Puppet, and why we'd want to do such a thing. Presented at the first Docker Manchester meetup on 21/07/16. GitHub repo with the configuration used during the demo is here: https://github.com/yankcrime/docker-puppet

1. Building Docker Images
With PuppetNick Jones, DataCentred
@yankcrime

2. Schedule
DataCentred overview
Why Docker
Why Puppet
Demo
Problems / solutions
Wrap-up

3. OpenStack
Keystone, Nova, Neutron, Glance, Cinder, Horizon,
etc.
KVM
Open vSwitch
Control, compute, network, data nodes

4. OpenStack Services
Galera
RabbitMQ
MongoDB
Memcache
Apache httpd
Haproxy & keepalived

5. Ceph
Loadbalancers
Gateways
Monitors
OSDs

6. Monitoring
Icinga2
Telegraf, InfluxDB, Grafana
ElasticSearch, Logstash, Kibana

7. Services
CI - Jenkins
DNS, TFTP, DHCP
IPAM
Mirrors

8. Puppet
Puppet Master
PuppetDB
Puppet CA
Foreman

9. ಠ_ಠ

10. Puppet
With Puppet you use a common language to
describe what you want your infrastructure to look
like, and Puppet makes it happen - and helps you
keep it that way.

11. OpenStack Infrastructure Overview

12. OpenStack Control Nodes

13. OpenStack Control Node

14. Why Docker
Consolidate OpenStack components into discrete
building blocks
Mix-and-match versions of components
Ease the pain of upgrades

15. Why Configuration Management
Need to build custom images
Harness the power of something that's the right tool
for the job
Puppet incumbent for configuration management,
would like to reuse data
Make the two work together

16. Assumptions
Containers should be ephemeral
Running SSH in a container is out
Running Puppet as an agent in a container is out

17. Typical Dockerfile
FROM phusion/baseimage:0.9.15
ENV HOME /root
ENV LANG en_US.UTF-8
RUN locale-gen en_US.UTF-8
RUN ln -s -f /bin/true /usr/bin/chfn
RUN apt-get update && apt-get -y upgrade
[..]
RUN apt-get remove -y --auto-remove openstack-dashboard-ubuntu-theme
ADD local_settings.py /etc/openstack-dashboard/local_settings.py
VOLUME ["/etc/openstack-dashboard"]
ADD openstack-dashboard.conf /etc/apache2/conf-available/openstack-dashboard.conf
ADD start_memcached.sh /etc/service/memcached/run
ADD start_apache2.sh /etc/service/apache2/run

18. With Puppet
FROM puppet:latest
MAINTAINER Nick Jones "nick@dischord.org"
ENV FACTER_role='horizon'
RUN puppet apply --verbose
--modulepath /puppet/modules
--hiera_config /puppet/hiera.yaml
--manifestdir /puppet/ /puppet/default.pp
RUN apt-get -y clean && rm -rf /puppet
EXPOSE 80
CMD ["/usr/bin/supervisord", "-n"]

19. Another Example
FROM puppet:latest
MAINTAINER Nick Jones "nick@dischord.org"
ENV FACTER_role='database'
ENV FACTER_container='dischord_database'
RUN puppet apply --debug --verbose
--modulepath /puppet/modules
--hiera_config /puppet/hiera.yaml
--manifestdir /puppet/ /puppet/default.pp
RUN apt-get -y clean && rm -rf /puppet
EXPOSE 3306
VOLUME /var/lib/mysql
CMD ["/usr/bin/supervisord", "-n"]

20. Database Container
database.yaml:
classes:
- '::profile::mariadb'
dischord_database.yaml:
databases:
'fever':
'user': 'fever'
'password': 'xxx'
'host': '%'
service:
'mariadb-server':
'command': '/usr/sbin/mysqld'

21. Puppet
class profile::mariadb {
include ::mysql::server
create_resources(::mysql::db, hiera('databases'))
}

22. Demo
Building a Horizon image

23. What doesn't work so well
Repo data in images
Breaks image layers philosophy
Puppet modules not handling container behaviour
Lack of support in Puppet's RAL for minimal distros

24. Solutions
Mount configuration data repo at build - Rocker!
Build API
OCI Image Format Specification
Alternative configuration management tools:
—mgmt
—Habitat

25. Questions?

26. References
https://puppet.com/blog/building-puppet-based-
applications-inside-docker
http://dischord.org/2016/03/27/docker-and-puppet/
https://github.com/purpleidea/mgmt
https://github.com/puppetlabs/puppet-rocker-demo
https://www.habitat.sh
https://github.com/grammarly/rocker