Using docker with configuration management. For all things Chef, presume I say "Puppet".

2. @ewindisch

3. Deploying with Docker
Atlanta Docker Meetup
2014.05.13

4. Do I still need Chef
<or insert tool here>?

5. There is no easy answer

8. Why do we still need
<or insert tool here>?

9. But… we have
Dockerfiles!

10. It’s a shell-script?
$ cat SomeApp/Dockerfile
FROM ubuntu:13.10
RUN apt-get update; apt-get install apache
RUN sed ’s/something/else/‘ /etc/apache/httpd.conf
ADD shell-script.sh
RUN shell-script.sh
RUN [‘/usr/bin/apachectl’, ‘start’]

11. How do we do it?
$ cat Dockerfile
FROM fedora
RUN yum update
yum -y install chef

12. Traditional Chef
Hardware
OS
Linux
Chef
Installs Chef
Runs
Configures

14. Images on HW
is usually mutable
Hardware
Image
Linux
Chef
Installs Chef
Image'
Linux
Chef
Creates
Replaces
Runs

16. Ephemeral environments
are (somewhat) immutable.
Hypervisor
Image
Linux
Chef
Runs
Image'
Linux
Chef
Chef
Runs
Configures
VM
Accesses
COW

18. Containers are like
ephemeral VMs*
* Docker containers don’t HAVE to be ephemeral,
but it’s TheRightThing
Docker
Image
Linux
Chef
Runs
Image'
Linux
Chef
Chef
Runs
Configures
Container
Accesses
COW
TM

19. Runtime Configuration
• One image, several
configurations
• Configuration based on
container environment
• Specify metadata or roles via
environment variables
(passed to ‘docker run -e’)

20. Chef-for-runtime
$ cat Dockerfile
FROM fedora
RUN yum update
yum -y install chef
ADD http://x/receipes.tar.gz /opt/chef"
ADD solo.rb /etc/chef/solo.rb"
CMD chef-solo -c /etc/chef/solo.rb ; !
apachectl start

21. Does it converge?
$ docker build —rm .
$ echo $? # pass or fail
(This is great use of Docker as an
alternative to VMs for testing Chef recipes
targeting non-Docker production systems)

22. Bootstrapping
Configuration Management
on every boot is expensive

23. Let us use images!

24. Build-time configuration
• Speed up Chef-based
deployments (do it once!)
• Eliminate run-time network
requirements
• Config-management CI

25. Chef-for-build
$ cat Dockerfile
FROM fedora
RUN yum update
yum -y install chef"
ADD http://x/receipes.tar.gz /opt/chef"
ADD solo.rb /etc/chef/solo.rb"
RUN chef-solo -c /etc/chef/solo.rb

26. Burning configuration
into images.
Docker ContainerInitiates Creates
Image
Linux
Chef
Chef
Runs
Configures
Build Creates

27. Expanded view:
Burning configuration into images.
Docker Image tagInitiates
Image'
Linux
Chef
Chef
Build
Image
Linux
Chef
Creates
Creates
Runs Creates
References
1
2

28. Anatomy of a Docker+Chef
build & run
Docker ContainerInitiates Creates
Image
Linux
Chef
Chef
Runs
Configures
Chef
Runs
Configures
Build Creates
Stage 1 Stage 2

29. Chef-for-all-the-things
$ cat Dockerfile
FROM fedora
RUN yum update
yum -y install chef
ADD http://x/receipes.tar.gz /opt/chef"
ADD solo-stage1.rb /etc/chef/solo-stage1.rb"
ADD solo-stage2.rb /etc/chef/solo-stage2.rb"
RUN chef-solo -c /etc/chef/solo-stage1.rb"
CMD chef-solo -c /etc/chef/solo-stage2.rb ;"
apachectl start