Run your continuous integration (CI) tests against your Engine Yard AppCloud environments - the exact same configuration you are using in production!
You're developing on OS X or Windows, deploying to Engine Yard AppCloud (Gentoo/Linux), and you're running your CI on your local machine or a spare Ubuntu machine in the corner of the office, or ... you're not running CI at all?
It's a nightmare. It was for me.
But now, Jenkins CI, the jenkins CLI project, and engineyard-jenkins now make CI easier to do than not to for Engine Yard AppCloud users.
And here's some logos:
gem install engineyard-jenkins
This will also install the jenkins CLI to interact with your Jenkins CI from the command line.
Using Engine Yard AppCloud "Quick Start" wizard, create an application with Git Repo git://github.com/engineyard/jenkins_holding_page.git (options: rails 3, passenger), and add your own SSH keys. This will create an environment called jenkins_server_production. Boot the environment as a Single instance (or Custom cluster with a single instance).
Optionally, though it is quite pretty, deploy/ship the jenkins_holding_page application and visit the HTTP link to see the remaining "Almost there..." instructions.
Finally, install Jenkins CI and rebuild the environment:
$ ey-jenkins install_server
When this completes, visit the URL or refresh the "Almost there..." page to see your Jenkins CI server.
Using the jenkins list CLI task you can also test there is a working server with no jobs:
For the Jenkins slaves' configuration, you'll need:
The jenkins_server_production instance public key:
$ ey ssh -e jenkins_server_production
# cat /home/deploy/.ssh/id_rsa.pub
Do those steps, copy down the configuration and you're done! Now, you either visit your Jenkins CI site or use jenkins list to see the status of your projects being tested.
Hosting Jenkins CI on Engine Yard AppCloud is optional; yet delightfully simple. Jenkins CI can be hosted anywhere.
If you host your Jenkins CI elsewhere then you need the following information about your Jenkins CI environment to be able to add EngineYard AppCloud instances as Jenkins nodes/slaves:
- Jenkins CI public host & port
- Jenkins CI's user's public key (probably at
/home/deploy/.ssh/id_rsa.pub) - Jenkins CI's user's private key path (probably
/home/deploy/.ssh/id_rsa)
This is the exciting part - ensuring that your CI tests are being run in the same environment as your production applications. In this case, on Engine Yard AppCloud.
It is assumed that you already have a production application environment (might have multiple applications in it):
In the Engine Yard AppCloud UI, create another environment that matches the production environment exactly (same Ruby, same set of applications, same Unix libraries).
Now, in just a few steps and you will have your applications' tests running in an environment that matches your production environment:
$ cd /my/project
$ ey-jenkins install .
Now edit cookbooks/jenkins_slave/attributes/default.rb to set up the Jenkins CI instance details gathered above.
$ ey recipes upload -e ci_demo_app_ci
$ ey recipes apply -e ci_demo_app_ci
Boot your ci_demo_app_ci environment, visit your Jenkins CI and WOW! jobs have been created, they are already running, and they are doing it upon your ci_demo_app_ci environment!
At any time from the command line you can use jenkins list to see the status of your jobs
- Do not use your production environment as your Jenkins CI slave. There are no guarantees what will happen. I expect bad things.
- You must name your CI environments with a suffix of
_cior_jenkins_slave. - You should not name any other environments with a suffix of
_cior_jenkins_slave; lest they offer themselves to your Jenkins CI as slave nodes. - Keep your production and CI environments exactly the same. Use the same Ruby implementation/version, same database, and include the same RubyGems and Unix packages. Why? This is the entire point of the exercise: to run your CI tests in the same environment as your production application runs.
For example, note the naming convention of the two CI environments below (one ends in _jenkins_slave and the other _ci).
When you boot your Engine Yard AppCloud CI environments, each resulting EC2 instance executes a special "jenkins_slave" recipe (see cookbooks/jenkins_slave/recipes/default.rb in your project). This does three things:
- Adds this instance to your Jenkins CI server as a slave
- Adds each Rails/Rack application for the AppCloud environment into your Jenkins CI as a "job".
- Commences the first build of any newly added job.
If your CI instances have already been booted and you re-apply the recipes over and over (ey recipes apply), nothing good or bad will happen. The instances will stay registered as slaves and the applications will stay registered as Jenkins CI jobs.
If a new application is on the instance, then a new job will be created on Jenkins CI.
To delete a job from Jenkins CI, you should also delete it from your AppCloud CI environment to ensure it isn't re-added the next time you re-apply or re-build or terminate/boot your CI environment. (To delete a job, use the Jenkins CI UI or jenkins remove APP-NAME from the CLI.)
In essence, to add new Rails/Rack applications into your Jenkins CI server you:
- Add them to one of your Engine Yard AppCloud CI environments (the one that matches the production environment where the application will be hosted)
- Rebuild the environment or re-apply the custom recipes (
ey recipes apply)
Thusly demonstrated below: the application/job "ci_demo_app" is in the middle of a build on its target slave "ci_demo_app_ci". See the AppCloud UI example above to see the relationship between the application/job names and the environment/slave names.
Yes. There are three simple ways to get Jenkins CI to run tests for your application ("create a job to run builds"). Above is the first: all "applications" on the Engine Yard AppCloud CI environment will automatically become Jenkins CI jobs. The alternates are:
- Use the
jenkins create .command from the jenkins CLI.
Pass the --assigned_node xyz flag to make the project's test be executed on a specific slave node. "xyz" is the name of another application on your AppCloud account; your tests will be executed on the same instance, with the same version of Ruby etc.
- Use the Jenkins CI UI to create a new job. As above, you can make sure the tests are run on a specific Engine Yard AppCloud instance by setting the assigned node label to be the same as another AppCloud application in your account that is being tested.
Specifically, Jenkins CI uses "labels" to match jobs to slaves. A common example usage is to label a Windows slave as "windows". A job could then be restricted to only running on slaves with label "windows". We are using this same mechanism.
In Jenkins CI, a "job" is one of your projects. Each time it runs your tests, it is called a "build".
It is often desirable to have your SCM trigger Jenkins CI to run your job build whenever you push new code.
- Go to the "Admin" section of your GitHub project
- Click "Service Hooks"
- Click "Post-Receive URLs"
- Enter the URL
http://HUDSON-CI-URL/job/APP-NAME/build - Click "Update Settings"
And here's a picture.
You can also use the "Test Hook" link to test this is wired up correctly.
Using the jenkins CLI:
jenkins build path/to/APP-NAME
You are triggering the build via a GET call to an URL endpoint. So you can also use curl:
curl http://HUDSON-CI-URL/job/APP-NAME/build
- Dr Nic Williams (drnic)
- Bodaniel Jeanes (bjeanes) - initial chef recipes for Jenkins server + slave
Copyright (c) 2010 Dr Nic Williams, Engine Yard
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