November 1, 2013

Vagrant, chef-solo, and databags learning experience

I've never had to use databags before in chef-solo, but this past week I needed to do some exploration with the opscode squid cookbook. Aside from the opscode databag docs, I couldn't find much good information on it, so here goes.


This part is straightforward. Just add a directory where your Vagrantfile lives and then include a databags_path in your provisioning block.

config.vm.provision :chef_solo do |chef|
  chef.data_bags_path = "data_bags"

  chef.run_list = [

Databag structure

Databags must be in a directory with a name matching the databag. Each individual databag must be a json file, the only requirement being a id element. The (truncated for clarity) directory structure looks like:

|-- Berksfile
|-- cookbooks
|   `-- squid
|-- data_bags
|   |-- squid_acl_actions
|   |   `-- rubygems.json
|   `-- squid_hosts
|       |-- everythingelse.json
|       `-- rubygems.json
`-- Vagrantfile

Databag items

Databag items themselves, as mentioned above, only need to contain an id element to be considered valid.

  "type": "dstdomain",
  "id": "everythingelse",
  "net": [

Using Databags

In the squid cookbook, databags are used to describe ACL rules and hosts which are retrieved using a library. To access them in your recipes (or libraries or resources), use the data_bag() method. In a chef server and chef client environment, you can leverage search(), but this is not available in chef-solo out of the box.

def squid_load_host_acl
  host_acl.push [group['id'],group['type'],host]
  rescue "no 'squid_hosts' data bag"

I hope this helps get started with databags, chef-solo, and vagrant.