Continuous deployment of Ansible Roles

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There are a lot of articles about Ansible with continuous deployment, but these are only about using Ansible as a tool to do continuous deployment. There is not much (Well, I can’t really find none) about continuous deployment on code changes in Ansible Roles/playbooks itself. But first: Why do you want to do that?

Well, it is very easy to make changes in a role or a playbook and deploy that to a (production) machine(s). I do hope that these changes are commited into the git repository (And pushed) so that changes on the host can be tracked back to the code. Hopefully you didn’t make any errors in the playbook or role so all will be fine during deployment and no unwanted downtime is caused, because nothing is tested.

When you are part of a team, this would be a downside of using Ansible. It is very easy to make changes to a playbook or a role locally and not commit it to the repository, deploy it to a production server and continue like it didn’t happen. You can make agreements on these kinds of procedures on when and how to execute playbooks, but you always have that coworker that don’t (or partly) want to follow procedures or just because of lack of time (“It has to be working this morning!” or just any other lame excuse to not test your code before deployment).

When the team/serverpark grows bigger and/or the company you work for matures and even has an SLA, you can’t just deploy any untested code anymore. You’ll have to make sure that changes you made to code is tested, like any other code. Application developers write unit tests on their code and the application is tested by either automated tests or by using test|qa team. Application development is not any different than writing software for your infrastructure, it all needs to be tested before you use it on production.

What I will describe in this blogpost is just a suggestion on how to do this. This might not be foolproof or maybe there are other or better ways on how todo this or … (Fill in some something other reason). As this is something that works for me, it might help you to create your own pipeline. YMMV.

I haven’t looked at all at Ansible Tower or the open sourced version, so it might be that parts or maybe all of what I am describing here can be done by Tower.

Before we do anyting, I’ll first describe how my Ansible setup looks like so we have some background before we do anything. All of my roles has their own git repository, including documentation and Jenkinsfiles. A Jenkinsfile is the Jenkins job configuration file that contains all steps that Jenkins will execute. Its the .travis.yml (Of Travis CI) file equivalent of Jenkins and we will come back later to this. I also have 1 git repository that contains all ansible data, like host_vars, group_vars and the inventory file.

I have a Jenkins running with the Docker plugin and once a job is started, a Docker container will be started and the job will be executed from this container. Once the Job is done (Succeeded or Failed doesn’t matter which), the container and all data in this container is removed.

Jenkins Jobs

All my Ansible roles has 3 jenkinsfiles stored in the git repository for the following actions:

  1. Molecule Tests
  2. Staging deployment
  3. Production deployment

Molecule Tests

The first job is that the role is tested with Molecule. With Molecule we create 1 or more Docker containers and the role is deployed to these containers. Once that is done, we do an idempotent check and with TestInfra we verify if installation/configuration is done correctly. We can also execute some commands to verify that the deployed service is running correctly. Once these tests are completed, we can successfully deploy the ansible role without any problems. (On this page I have described some information on Molecule.)

How does the Jenkinsfile looks like:

node() {
    try {
        stage ("Get Latest Code") {
            checkout scm
            sh 'git rev-parse HEAD > .git/commit-id'
        }
        stage ("Install Application Dependencies") {
            sh 'sudo pip install --upgrade ansible==${ANSIBLE_VERSION} molecule==${MOLECULE_VERSION} docker'
        }
        stage ("Executing Molecule lint") {
            sh 'molecule lint'
        }
        stage ("Executing Molecule create") {
            sh 'molecule create'
        }
        stage ("Executing Molecule converge") {
            sh 'molecule converge'
        }
        stage ("Executing Molecule idemotence") {
            sh 'molecule idempotence'
        }
        stage ("Executing Molecule verify") {
            sh 'molecule verify'
        }
        stage('Tag git'){
            def commit_id = readFile('.git/commit-id').trim()
            withEnv(["COMMIT_ID=${commit_id}"]){
                sh '''#!/bin/bash
                if [[ $(git tag | grep ${COMMIT_ID} | wc -l) -eq 1 ]]
                    then    echo "Tag already exists"
                    else    echo "Tag will be created"
                            git config user.name "jenkins"
                            git config user.email "jenkins@localhost"
                            git tag -a $COMMIT_ID -m "Added tagging"
                            git push --tags
                fi
                '''
            }
        }
        stage('Start Staging Job') {
            def commit_id = readFile('.git/commit-id').trim()
            withEnv(["COMMIT_ID=${commit_id}"]){
                build job: 'ansible-access-2-staging', wait: false, parameters: [string(name: 'COMMIT_ID', value: "${COMMIT_ID}") ]
            }
        }
    } catch(all) {
        currentBuild.result = "FAILURE"
        throw err
    }
}

First stage of the Job is the checkout of the sourcecode of the git repository, so that we have data in the container. We get the latest git commit id, because I use this id to create a tag in git once the Molecule Tests succeeds.

First Molecule action is the lint. First we do some linting on the role and test files to make sure it is compliant. If it find some errors, it fails quickly and we can fix it. Then it proceeds with the Molecule actions create, converge, idemptence and verify. For those who are familiar with Molecule will notice that I use different stages for each action and not 1 stage which executes molecule test.

Stages overview of Jenkins job.

I use separate stages with single commands so I can quickly see on which part the job fails and focus on that immediately without going to the console output and scrolling down to see where it fails. After the Molecule verify stage, the Tag git stage is executed. This will use the latest commit id as a tag, so I know that this tag was triggered by Jenkins to run a build and was successful.

Last stage in the job is to start the 2nd job in Jenkins. This stage will start the job ansible-access-2-staging with the COMMIT_ID as parameter to the job and in the background (wait: false).

Currently, the Molecule configuration only has 1 “default” scenario. If I had more scenarios than the Jenkinsfile had probably a lot more stages or maybe more Jenkinsfiles.

Staging deployment

The first job was executed correctly and now this job is triggered. As mentioned before, the commit id of the previous job is passed into this job. The goal for this job is to deploy the role to an staging server and validate if everything is still working correctly. In this case we will execute the same tests on the staging staging as we did with Molecule, but we can also create an other test file and use that. In my case, there is only one staging server but it could also be a group of servers.

The Jenkinsfile for this job looks like this:

node() {
    try {
        stage ("Get the Code") {
            checkout scm: [$class: 'GitSCM', branches: [[name: "refs/tags/${params.COMMIT_ID}"]], extensions: [[$class: 'RelativeTargetDirectory', relativeTargetDir: 'ansible-access']], userRemoteConfigs: [[url: 'ssh://git@192.168.1.206:2222/ansible/access.git']]]
            checkout scm: [$class: 'GitSCM', branches: [[name: '*/master']], extensions: [[$class: 'RelativeTargetDirectory', relativeTargetDir: 'environment']], doGenerateSubmoduleConfigurations: false, userRemoteConfigs: [[url: 'ssh://git@192.168.1.206:2222/ansible/environment.git']]]
            sh 'pwd > workspace'
        }
        stage ("Install Application Dependencies") {
            sh 'sudo pip install --upgrade ansible==${ANSIBLE_VERSION} testinfra docker'
        }
        stage ("Execute role on host(s)") {
            dir("environment") {
                sh "ansible-playbook -i hosts -l staging playbooks/ansible-access.yml"
            }
        }
        stage ("Test Role execution") {
            workspace = readFile('workspace').trim()
            withEnv(["WORKSPACE_DIR=${workspace}", "MOLECULE_INVENTORY_FILE=${workspace}/environment/hosts"]){
                dir("environment/") {
                    sh "testinfra --connection=ansible --ansible-inventory=hosts --hosts=staging ${WORKSPACE_DIR}/ansible-access/molecule/default/tests/test_default.py --verbose"
                }
            }
        }
        stage('Tag git'){
            withEnv(["COMMIT_ID=${params.COMMIT_ID}_staging"]){
                dir("ansible-access/") {
                    sh '''#!/bin/bash
                    if [[ $(git tag | grep "${COMMIT_ID}" | wc -l) -eq 1 ]]
                        then    echo "Tag already exists"
                        else    echo "Tag will be created"
                                git config user.name "jenkins"
                                git config user.email "jenkins@localhost"
                                git tag -a $COMMIT_ID -m "Added tagging"
                                git push --tags
                    fi
                    '''
                }
            }
        }
        stage('Start Production Job') {
            build job: 'ansible-access-3-production', wait: false, parameters: [string(name: 'COMMIT_ID', value: "${params.COMMIT_ID}") ]
        }
    } catch(all) {
        currentBuild.result = "FAILURE"
        throw err
    }
}

The first stage is to checkout 2 git repositories: The Ansible Role and the 2nd is my “environment” repository that contains all Ansible data and both are stored in their own sub directory. With the Ansible role we checkout the provided tag refs/tags/${params.COMMIT_ID}. I also had to configure the url for the git repositories. Last step is to create a file that holds the output of the pwd file. We need this location in a later stage.

The 2nd Stage is to install the required applications, so not very interesting. The 3rd stage is to execute the playbook. In my “environment” repository (That holds all Ansible data) there is a playbooks directory and in that directory contains the playbooks for the roles. For deploying the ansible-access role, a playbook named ansible-access.yml is present and will be use to install the role on the host:

---
- hosts: all:!localhost
  become: True
  roles:
    - role: ansible-access

Very basic/simple. The 4th stage is to execute the Testinfra test script from the molecule directory to the staging server to verify the correct installation/configuration. In this case I used the same tests as Molecule, but I could also create a seperate file with some extra or other tests to verify the correct behaviour of the host.

And when all tests are complete, we create a new tag. In this job we create a new tag ${params.COMMIT_ID}_staging and push it so we know that the provided tag is deployed to our staging server.

With the last stage, we start the 3rd and last job, the job to deploy the role on the rest of the servers.

Production deployment

This is the job that deploys the Ansible role to the rest of the servers. This Jenkinsfile looks almost the same as the previous one, but with a few exceptions.

node() {
    try {
        stage ("Get the Code") {
            checkout scm: [$class: 'GitSCM', branches: [[name: "refs/tags/${params.COMMIT_ID}"]], extensions: [[$class: 'RelativeTargetDirectory', relativeTargetDir: 'ansible-access']], userRemoteConfigs: [[url: 'ssh://git@192.168.1.206:2222/ansible/access.git']]]
            checkout scm: [$class: 'GitSCM', branches: [[name: '*/master']], extensions: [[$class: 'RelativeTargetDirectory', relativeTargetDir: 'environment']], doGenerateSubmoduleConfigurations: false, userRemoteConfigs: [[url: 'ssh://git@192.168.1.206:2222/ansible/environment.git']]]
            sh 'pwd > workspace'
        }
        stage ("Install Application Dependencies") {
            sh 'sudo pip install --upgrade ansible==${ANSIBLE_VERSION} testinfra docker'
        }
        stage ("Execute role on host(s)") {
            dir("environment") {
                sh "ansible-playbook -i hosts -l 'all:!localhost:!staging' playbooks/ansible-access.yml"
            }
        }
        stage ("Test Role execution") {
            workspace = readFile('workspace').trim()
            withEnv(["WORKSPACE_DIR=${workspace}", "MOLECULE_INVENTORY_FILE=${workspace}/environment/hosts"]){
                dir("environment") {
                    sh "testinfra --connection=ansible --ansible-inventory=hosts --hosts='all:!localhost:!staging' ${WORKSPACE_DIR}/ansible-access/molecule/default/tests/test_default.py --verbose"
                }
            }
        }
        stage('Tag git'){
            withEnv(["COMMIT_ID=${params.COMMIT_ID}_production"]){
                dir("ansible-access") {
                    sh '''#!/bin/bash
                    if [[ $(git tag | grep "${COMMIT_ID}" | wc -l) -eq 1 ]]
                        then    echo "Tag already exists"
                        else    echo "Tag will be created"
                                git config user.name "jenkins"
                                git config user.email "jenkins@localhost"
                                git tag -a $COMMIT_ID -m "Added tagging"
                                git push --tags
                    fi
                    '''
                }
            }
        }
    } catch(all) {
        currentBuild.result = "FAILURE"
        throw err
    }
}

With the 3rd stage “Execute role on host(s)” we use an different limit. We now use all:!localhost:!staging to deploy to all hosts, but not to localhost and staging. Same is for the 4th stage, for executing the tests. As the last stage in the job, we create a tag ${params.COMMIT_ID}_production and we push it. Once we see this tag in our repository, we know that the changes is installed correctly on all servers.

Keep in mind that this can only be successful if you use proper and correct tests. You’ll really need to be sure that your tests is covering all of the components that is changed by your role. This deployment will fail or succeed with the quality of your tests.

Good luck and if you have suggestions please let me know.

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