#Head Chef Trust your environments…
Manage Chef Environments with Berkshelf, Ridley, and Git
#Installation Add Head Chef to your repository's Gemfile:
Or run in as a standalone
gem install head_chef
Head Chef manages Chef Enviroments using Berkshelf. Chef Server connections are made via Ridley, and are controlled by a
knife.rb file, which should be located in a
.chef directory. Head Chef will use the closest
.chef/knife.rb found in its or its parents directories, identical to the Chef CLI tool Knife.
Head Chef must be run in the root of a
Note: It is up to the user to manage the
The following commands are under
head-chef env and perform actions on Chef Environments.
By default, the Chef Environment used will match the current
For example if the current git branch is
test, these commands will be run against the Chef Environment named
test, if it exists.
These commands can be passed the following arguments:
-e <environment>, Applies to the specified Chef Environment
###diff View cookbook version constraint diff between local Berksfile and Chef Environment.
$ head-chef env diff
Loading environment test from chef server... Loading cookbooks from berkshelf... Calculating diff... ADD: nginx: 2.0.4 apt: 2.3.0 bluepill: 2.3.0 rsyslog: 1.9.0 build-essential: 1.4.2 ohai: 1.1.12 runit: 1.4.0 yum: 2.4.2 REMOVE: java: 1.15.4 windows: 1.11.0 chef_handler: 1.1.4 aws: 1.0.0
###list View Chef Environment's cookbook version constraints
$ head-chef env list
COOKBOOKS: aws: 1.0.0 chef_handler: 1.1.4 java: 1.15.4 windows: 1.11.0
Berksfile's cookbook version constraints with Chef Environment.
The Chef Environment will be created if it does not exist.
sync ensures all cookbooks in the environment are present on Chef Server, and are identical to the source specified in the
Berksfile, minus files specified via
$ head-chef env sync
A conflict will arise when a cookbook to be uploaded matches a cookbook on Chef Server in version number, but does not have the same content. In general, conflicts will arise when a cookbook has been updated, but the version number was not changed. More often than not, this should be resolved by simply updating the cookbook version number, however, the force option can be used to overwrite the remote cookbook on Chef Server with the local version of the cookbook. This should only be used in exceptional circumstances.
$ head-chef env sync --force
Determing side effects of sync with chef environment test... Uploading cookbooks to chef server... Using nginx (2.0.4) Using apt (2.3.0) Using bluepill (2.3.0) Using rsyslog (1.9.0) Using build-essential (1.4.2) Using ohai (1.1.12) Using runit (1.4.0) Using yum (2.4.2) Uploading nginx (2.0.4) to: 'https://api.opscode.com:443/organizations/my-org' Uploading apt (2.3.0) to: 'https://api.opscode.com:443/organizations/my-org' Uploading bluepill (2.3.0) to: 'https://api.opscode.com:443/organizations/my-org' Uploading rsyslog (1.9.0) to: 'https://api.opscode.com:443/organizations/my-org' Uploading build-essential (1.4.2) to: 'https://api.opscode.com:443/organizations/my-org' Uploading ohai (1.1.12) to: 'https://api.opscode.com:443/organizations/my-org' Uploading runit (1.4.0) to: 'https://api.opscode.com:443/organizations/my-org' Uploading yum (2.4.2) to: 'https://api.opscode.com:443/organizations/my-org' Applying Berksfile.lock cookbook version to environment test... Using nginx (2.0.4) Using apt (2.3.0) Using bluepill (2.3.0) Using rsyslog (1.9.0) Using build-essential (1.4.2) Using ohai (1.1.12) Using runit (1.4.0) Using yum (2.4.2)
Determing side effects of sync with chef environment readme-example... The following cookbooks are in conflict: test_cookbook: 0.1.0 Use --force to sync environment
Head Chef is meant to be run inside a master cookbook. A master cookbook is simply a git repository which has branches associated with Chef Environments. Each branch has a
Berksfile representing that Chef Environment's cookbook version constraints.
Note: These workflows are opinionated and assume the following:
- Development and Production Chef Orgs
##Testing/Development Chef Environments can easily be created with Head Chef to be used for testing/development purposes:
- Checkout master cookbook
- Create a new branch
head-chef env sync
These environments can be versioned by committing the branch back to the master cookbook, via pull request.
##Cookbook Development The following outlines a potential cookbook workflow. It does not involve Head Chef, however, creating/syncing environments with Head Chef provides the benefit of preventing cookbook leakage. All cookbooks that would be used within the environment are pinned at specific versions, and this is key for allowing automated cookbook promotion. While still in development, it is important to test cookbooks changes, making sure they do not break other test environments in use.
- Update Chef cookbook until it is deemed ready for promotion (e.g. new version)
- Release new version of cookbook (merge to master)
- Upload new version of cookbook to Chef Server, in the development Chef Org
- Queue CI server build where role cookbooks are tested against
_defaultChef Environment in development Chef Org.
_defaultChef Environment holds latest cookbooks, not present in environment constraints
- Successful test of role cookbooks indicates environments in master cookbook can be updated
##Cookbook Promotion/Production Updates to production occur in a similar fashion, but will most likely have more systems in place. Therefore, let's outline a full Chef Cookbook update workflow in production.
- Update Chef cookbook until it is deemed ready for production (e.g. new version)
- Checkout master cookbook
- Checkout/create branch matching Chef Environment
Berksfileto include updated cookbook
Berksfile.lockto include updated cookbook as well as resolve any new dependencies
- Make pull request to master cookbook
- Pull request queues CI server build where role cookbooks are tested in new/updated environment
- Once environment build passes, pull request is ready for merge
- After merge, environment and cookbooks can be updated via
head-chef env sync
Environment changes follow the same path, but exclude the cookbook update