The document discusses the automation of Docker containers using Puppet, detailing two methods for running code: Puppet apply and Puppet agent. It provides examples for building and running containers with specific configurations, such as installing NTP and Nginx. The document also touches on the nuances of running Puppet agents inside containers and the conditions under which they operate.

1. Automating Docker
Containers with Puppet
Kylo Ginsberg
kylo@puppetlabs.com
@kylog
irc: kylo

2. Puppet?

3. So you can write:
package { ‘ntp’:!
ensure => installed,!
}!
file { ‘/etc/ntp.conf’:!
ensure => file,!
source => ‘/root/example/ntp.conf’,!
mode => ‘0444’,!
}!
service { ‘ntp’:!
ensure => running,!
}

4. Forge

5. Instead write
include ‘::ntp'
or customize:
class { '::ntp':!
servers => [ 'ntp1.corp.com', 'ntp2.corp.com' ],!
}

6. Puppet
System Configuration
Declarative Language
Resource Abstraction

7. Two ways to run code:
puppet apply
puppet agent

8. Docker and Puppet
1. Building containers!
2. Running containers!
3. Running inside containers

9. Building: puppet apply
FROM ubuntu:14.04
!
RUN apt-get -y update
RUN apt-get -y install ruby
RUN gem install puppet
RUN puppet module install puppetlabs/ntp
RUN puppet apply -e 'include "::ntp"'

10. Building: puppet agent
FROM ubuntu:14.04
!
RUN apt-get -y update
RUN apt-get -y install ruby
RUN gem install puppet
RUN puppet agent -t —server my_host

11. Building: puppet apply
FROM jamtur01/puppetbase
MAINTAINER James Turnbull "james@lovedthanlost.net"
!
RUN apt-get -y -q install wget git-core
ADD Puppetfile /
RUN librarian-puppet install
RUN puppet apply --modulepath=/modules -e "class
{ 'nginx': }"
RUN echo "daemon off;" >> /etc/nginx/nginx.conf
EXPOSE 80
CMD ["nginx"]

12. System?

13. Running docker with puppet
docker::run { 'helloworld':
image => 'ubuntu:precise',
command => '/bin/sh -c "while true; do echo hello
world; sleep 1; done"',
}

14. Puppet Agent on a
Container?

15. Container == VM ?

16. Puppet Agent on a
Container?
Only if you’re treating it as a VM

17. Container == PID?
No syslogd, no sshd, no puppet agent

18. Container == PID?

19. Bye

20. Idempotence
The state looked like this
I ran the function again
The state looked like this