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Chef Tips and Tools

Create New Cookbook

Creating new cookbook consists of several steps:

  1. We have cookbook template which have all the necessary bits to speed up cookbook creation. To init new cookbook from template, do the following:

    1. Clone the template into new cookbook directory: 
      git clone git@gitlab.com:gitlab-cookbooks/template.git gitlab_newcookbook
      Please use the gitlab_ prefix for new cookbooks names.
    2. Replace the template with gitlab_newcookbook everywhere: 
      find * -type f | xargs -n1 sed -i 's/template/gitlab_newcookbook/g'
ls .kitchen*yml | xargs -n1 sed -i 's/template/gitlab_newcookbook/g'
      This will also update badges in README.md, attributes, and recipes.
    3. At this point, you have a fully functional initial commit with passing tests (see the Testing section in cookbooks README.md for details), and you can rewrite git commit history from template to you cookbook: 
      git checkout --orphan latest && \
git add -A && \
git commit -am 'Initial commit'
      ☝️ the above may ask for GPG password if you sign your commits, so its separated from the branch switch below 👇 
      git branch -D master && \
git branch -m master && \
sed -i 's/template/gitlab_newcookbook/' .git/config

  2. Now its time to create two repos for your new cookbook. The main one, on gitlab.com, is used for everyday work, and template points to .com by default. The mirror cookbook on ops.gitlab.net is used by chef-server when gitlab.com is down, and should never be pushed directly to.

    1. Create a new project in gitlab-cookbooks namespace (please use gitlab_ prefix)
    2. Follow these instructions to setup mirroring on ops.

  3. Do a git push origin master and verify that the repository is mirrored to ops in few minutes.

  4. Last step: tighten up push/merge rules to enforce some consistency of the cookbook. Since ops.gitlab.net is only mirror, and should never be used directly, the following is done only cookbook located on gitlab.com:

    1. Set some description in Settings -> General.
    2. Check "Merge request approvals" and add @gitlab-com/gl-infra group to approvers under Settings -> General.
    3. Allow merge only with green pipelines and resolved discussions there too.
    4. Set "Check whether author is a GitLab user" and "Prevent committing secrets to Git" under Settings -> Repository. Make sure master branch is protected there too.
    5. Uncheck the "Public pipelines" under Settings -> Pipelines.

Go to the chef-repo and edit the Berksfile to add the new cookbook. Be sure that you add version pinning and point it to the ops repo. Next, run berks install to download the cookbook for the first time, commit, and push. Finally, run berks upload <cookbookname> to upload the cookbook to the Chef server.

To apply this uploaded cookbook to a new environment follow the steps below

ChefSpec and test kitchen

For cookbooks with Makefiles in them, see the README.md for testing instructions.

Some points that might not be in the README.md, for historical reasons: Builds happen in the "GitLab Dev" project. When running from your own machine for initial testing, you need to export DIGITALOCEAN_ACCESS_TOKEN and DIGITALOCEAN_SSH_KEY_IDS. To get values for these:

  • Look in 1password for "DIGITALOCEAN_ACCESS_TOKEN for gitlab-cookbooks CICD".
  • Upload your SSH key to the GitLab Dev project, then and obtain the ID value with: curl -s -S -X GET https://api.digitalocean.com/v2/account/keys/<fingerprint> -H "Authorization: Bearer $DIGITALOCEAN_ACCESS_TOKEN" | jq .ssh_key.id. The fingerprint is visible in the web UI after upload, and can be copy/pasted as is into the API URL. The ID returned is what you put into DIGITALOCEAN_SSH_KEY_IDS; if it outputs 'null', remove the pipe to jq, and see what the API is saying.

If you're using a Yubikey, you probably also want to export GITLAB_DO_SSH_KEY= to set it explicitly to null, so it doesn't try and use a non-existent SSH key off disk, and just use your ssh-agent/gpg-agent/whatever you've got

ChefSpec

ChefSpec and test kitchen are two ways that you can test your cookbook before you commit/deploy it. From the documentation:

ChefSpec is a framework that tests resources and recipes as part of a simulated chef-client run. ChefSpec tests execute very quickly. When used as part of the cookbook authoring workflow, ChefSpec tests are often the first indicator of problems that may exist within a cookbook.

To get started with ChefSpec you write tests in ruby to describe what you want. An example is:

file '/tmp/explicit_action' do
  action :delete
end

file '/tmp/with_attributes' do
  user 'user'
  group 'group'
  backup false
  action :delete
end

file 'specifying the identity attribute' do
  path   '/tmp/identity_attribute'
 action :delete
end

There are many great resources for ChefSpec examples such as the ChefSpec documentation and the ChefSpec examples on GitHub.

Test Kitchen/KitchenCI

Test Kitchen/KitchenCI is a integration testing method that can spawn a VM and run your cookbook inside of that VM. This lets you do somewhat more than just ChefSpec and can be an extremely useful testing tool.

To begin with the KitchenCI, you will need to install the test-kitchen Gem gem install test-kitchen. It would be wise to add this to your cookbook's Gemfile.

Next, you'll want to create the Kitchen's config file in your cookbook directory called .kitchen.yml. This file contains the information that KitchenCI needs to actually run your cookbook. An example and explanation is provided below.

---
driver:
  name: vagrant

provisioner:
  name: chef_zero

platforms:
  - name: centos-7.1
  - name: ubuntu-14.04
  - name: windows-2012r2

suites:
  - name: client
    run_list:
      - recipe[postgresql::client]
  - name: server
    run_list:
      - recipe[postgresql::server]

This file is probably self-explanatory. It will use VirtualBox to build a VM and use chef_zero as the method to converge your cookbook. It will run tests on 3 different OSes, CentOS, Ubuntu, and Windows 2012 R2. Finally, it will run the recipes listed below based on the suite. The above config file will generate 6 VMs, 3 for the client suite and 3 for the server suite. You can customize this however you wish. It is possible to run KitchenCI for an entire deployment, however I don't think our chef-repo is set up in such a way.

As always, there are many resources such as the KitchenCI getting started guide and the test-kitchen repo.

Test cookbook on a local server

If you wish to test a cookbook on your local server versus KitchenCI, this is totally possible.

The following example is a way to run our GitLab prometheus cookbook locally.

mkdir -p ~/chef/cookbooks
cd ~/chef/cookbooks
git clone git@gitlab.com:gitlab-cookbooks/gitlab-prometheus.git
cd gitlab-prometheus
berks vendor ..
cd ..
chef-client -z -o 'recipe[gitlab-prometheus::prometheus]'

The chef-client -z -o in the above example will tell the client to run in local mode and to only run the runlist provided. You can substitute any cookbook you wish, including your own. Do keep in mind however that this may still freak out when a chef-vault is involved.

Update cookbook and deploy to production

When it comes time to edit a cookbook, you first need to clone it from its repo, most likely in https://gitlab.com/gitlab-cookbooks/.

Once you make your changes to a cookbook, you will want to be sure to bump the version number in metadata.rb as we have versioning requirements in place so Chef will not accept a cookbook with the same version, even if it has changed. Commit these changes and submit a merge request to merge your changes.

Once your changes are merged, the new cookbook will be uploaded to Chef server automatically as part of a CI pipeline.

To apply this uploaded version to a new environment follow the steps below

Rollback cookbook

With the advent of environment pinned versions, rolling back a cookbook is as simple as changing the version number back to the previous one in the respective environment file.

There is no need to delete the version, we can roll forward and upload a corrected version in its place.

Chef Environments and Cookbooks

By utilizing environments in chef we are able to roll out our cookbooks to a subset of our infrastructure. As an environment we divide up our infrastructure the same way was in terraform:

  • stg (staging)
  • pre (pre production)
  • cny (canary)
  • prd (production)

with the addition of the chef default environment:

To see the nodes in an environment use a knife search command such as:

knife search node 'chef_environment:stg'|grep Name|sort

Each environment has a locked version for each GitLab cookbook which looks like this:

"gitlab-common": "= 0.2.0"

The pattern matching follows the same syntax as gem or berks version operators (ie. <, >, <=, >=, ~>, =). This allows us to roll out a cookbook one environment at a time. The workflow for this would look as follows.

The version should be on the chef server when it was merged into master, but is only actively being applied to nodes in the _default environment, since _default has no version constraints. The next steps are the same as for any omnibus deploy:

  1. deploy and test in staging
  2. edit the environment file
  3. upload the environment file knife environment from file path/to/stg.json
  4. verify changes (e.g. run chef-client on a server)
  5. deploy and test in pre-production
  6. edit the environment file
  7. upload the environment file knife environment from file path/to/pre.json
  8. verify changes (e.g. run chef-client on a server)
  9. deploy and test in canary
  10. edit the environment file
  11. upload the environment file knife environment from file path/to/cny.json
  12. verify changes (e.g. run chef-client on a server)
  13. deploy and run in production
  14. edit the environment file
  15. upload the environment file knife environment from file path/to/prd.json
  16. verify changes (e.g. run chef-client on a server)

This method does come with inherent risks: if this is done sloppily, it is possible that cookbook version can fall under the table and never be applied to an environment. We have need a check in place to ensure that this does not happen. (e.g. compare the latest version on the chef server with the version in each environment, as well as the environments with each other).

Run chef client in interactive mode

Really useful to troubleshoot.

Starting from the chef-repo folder run the following command:

$ chef-shell -z -c .chef/knife.rb

In here you can type help to get really useful help, but then for instance you can do this

> nodes.search('name:node-name-in-chef')

And then examine this node from chef's perspective

References