Chef orchestration

Chef is a configuration management tool that automates the deployment and management of applications and infrastructure. It uses a domain-specific language (DSL) for writing system configuration "recipes." These recipes are stored in "cookbooks" that can be shared and reused across different systems.

Each cluster-init spec can reference one or more Chef roles and/or cookbook recipes that need to be executed on the booting VM.

Project Structure

The specs directory in a project can also contain a chef subdirectory. This directory contains three directories: site-cookbooks (for cookbook definitions), data_bags (data bag definitions), and roles (Chef role definition files):

      myproject
          ├── specs
          │   ├── default
          │     └── chef
          │         ├── site-cookbooks
          │         ├── data_bags
          │         └── roles

Chef Runlists

You can specify a run_list at the project or spec level within your project.ini:

[spec scheduler]
run_list = role[a], recipe[b]

When a node includes the scheduler spec, the run_list you define automatically appends to any previously defined run_list. For example, if the run_list under [configuration] is run_list = recipe[test], the final run_list is run_list = recipe[cyclecloud], recipe[test], role[a], recipe[b], recipe[cluster_init].

You can also overwrite run_list at the spec level on a node. This replacement run_list removes any run_list included in project.ini. For example, you can change the node definition to the following definition:

[cluster-init test-project:scheduler:1.0.0]
run_list = recipe[different-test]

Using this run_list causes the run_list defined in the project to be ignored. The final run_list on the node becomes run_list = recipe[cyclecloud], recipe[test], recipe[different-test], recipe[cluster_init].

Custom Chef and composable specs

Each spec can contain a chef directory. Before you converge a node, the process untars and extracts each spec into the local chef-repo, replacing any existing cookbooks, roles, and data bags with matching names. The process follows the order in which you define the specs, so the last defined spec wins if there's a naming conflict.

File locations

When you upload your project contents, CycleCloud zips the three custom Chef directories and syncs them to your target locker, at (locker)/projects/(project)/(version)/(spec_name)/chef.

The node downloads the zipped Chef files during the bootstrapping phase of node startup. The node downloads the files to $JETPACK_HOME/system/chef/tarballs*, unzips them to $JETPACK_HOME/system/chef/chef-repo/, and uses them to converge the node.

Jetpack download resource provider

The following example shows how to create a jetpack_download lightweight resource provider for Chef users:

jetpack_download "big-file1.tgz" do
  project "my-project"
  end

In Chef, the default download location is #{node[:jetpack][:downloads]}. To change the file destination, use the following code:

jetpack_download "foo.tgz" do
  project "my-project"
  dest "/tmp/download.tgz"
end

When you use the command within Chef, you must specify the project.