Elegant deployment with Fabric and Puppet.
Loom does the stuff Puppet doesn't do well or at all: bootstrapping machines, giving them roles, deploying Puppet code and installing reusable Puppet modules. It's useful for both serverless and master/agent Puppet installations.
$ sudo pip install loom
First of all, you create fabfile.py and define your hosts:
from fabric.api import *
from loom import puppet
from loom.tasks import *
env.user = 'root'
env.environment = 'prod'
env.roledefs = {
'app': ['prod-app-1.example.com', 'prod-app-2.example.com'],
'db': ['prod-db-1.example.com'],
}
You can then define any third-party Puppet modules you want in a file called Puppetfile:
forge "http://forge.puppetlabs.com"
mod "puppetlabs/nodejs"
mod "puppetlabs/mysql"
(This is for librarian-puppet, a tool for installing reusable Puppet modules. It can also install from Git, etc.)
Your own modules are put in a directory called modules/ in the same directory as fabfile.py. Roles are defined in a magic module called roles which contains manifests for each role. (If you've used Puppet before, this is a replacement for node definitions.)
For example, modules/roles/manifests/db.pp defines what the db role is:
class roles::db {
include mysql
# ... etc
}
And that's it!
Let's set up a database server. First, bootstrap the host (in this example, the single db host you defined in env.roledefs):
$ fab -R db puppet.install
Then install third party Puppet modules, upload your local modules, and apply them:
$ fab -R db puppet.update puppet.apply
Every time you make a change to your modules, you can run that command to apply them. Because this is just Fabric, you can write a task in fabfile.py to do it too:
@task
def deploy_puppet():
execute(puppet.update)
execute(puppet.apply)
Then you could use the included "all" task to update Puppet on all your hosts:
$ fab all deploy_puppet
It's only been tested on Ubuntu 12.04. I would like to support more things. Send patches!
Look at the source for now. It's all Fabric tasks, and they're pretty easy to read. (Sorry.)