Jenkins as code, part 1: Setting up Jenkins in Docker

I hate doing things manually, I really do.

Log into an UI, do some clicks here and there to be able to have something created or configured. It is error prone (you can easily forget something or make a typo) and it is stupid and/or boring (Especially if you need to do this on a routine basis). If you can change something in a UI, then someone is able to change that as well and even do that without you knowing that it is changed (Or viceversa ;-)). So doing things manually is not the way forward and we should focus on automation. Automation is one of the pillars of doing DevOps, so we should always automate things right?

What people do probably not know, Jenkins is a tool that can be fully automated, you only have to know how. (And based on some posts on for example Reddit, I don’t think people knows that this is even possible).

Jenkins as code

So lets dive into, what I would say as: Jenkins as code.

This will basically be a 2 part blog post where we will discuss the following:

  1. This part where we will create a Docker image, containing Jenkins with its configuration files and plugins;
  2. The next part, where we will create a shared library and use that in a Jenkinsfile, with jobs we load via a “specifications” repository;

Before we do anything I just want to remind you that this is just 1 way to achieve a Jenkins as code setup. It does not mean that this is the only or the best way, it is just one way. Just like that there are 1000 ways to go to Rome. Next to that, these blog posts and the code in the Github repository will help you kickstart your own setup and by no means you can just run it on a production environment and blame me if something is not working fine. I am not a groovy expert and I can do some basic things, so don’t expect a new world wonder. During the blog posts I will tell you how I was able to do things, so you can redo it all yourself (and compare it with the code in the Github repository) and build it on your own terms/setup.

In both blog posts, you will see a lot of code and commands popping up. But no worries, all code is available on my Github in repository https://github.com/dj-wasabi/blog-jenkins-as-code . So lets start with the first part: Setting up Jenkins.

Docker(file)

We will create a Docker image, based on “jenkins/jenkins:lts” Docker image, install Docker and configure it with the configuration-as-code plugin included with several yaml files that are used for configuring Jenkins. And as part of the Github repository, we have a docker-compose.yaml file which we can use to boot our setup.

Lets start with the Dockerfile.

USER root
RUN groupadd docker && \
    curl -fsSL https://get.docker.com -o get-docker.sh && \
    sh get-docker.sh && \
    usermod -aG root jenkins && \
    usermod -aG docker jenkins
USER jenkins

Lets discuss this first, the “jenkins/jenkins:lts” Docker image does not contain the docker application, so we need to install that and make sure that the “jenkins” user is part of the “root” and “docker” group. We need Docker in this image, as each Jenkins job will run in its own Docker container.

ENV CASC_JENKINS_CONFIG=/var/jenkins_home/casc

We need set an environment variable named CASC_JENKINS_CONFIG, which we basically tell Jenkins where the configuration-as-code yaml files can be found.

COPY casc/ /var/jenkins_home/casc
COPY plugins.txt /usr/share/jenkins/plugins.txt
RUN /usr/local/bin/install-plugins.sh < /usr/share/jenkins/plugins.txt

Then we will copy the contents on the casc directory to the earlier mentioned directory and we place the file with all of our plugins into a specific directory. Then we run the install-plugins.sh script so we can download and install all the plugins that we need in our setup.

And that is our Dockerfile, easy right? This will allow us to build a Jenkins Docker image, with all of our files and configuration that will lead to an Jenkins environment we want to have. We can deploy this on some host running Docker or even make some additional changes to make it work in Kubernetes.

Plugins

Lets go to the plugins.txt file, as this one is a bit easier to explain than the casc files.

We need to create a plugins.txt that contains all of the plugins we want to make use, so how do we do that. I manually (oh yes, sorry! :)) started a Jenkins container and followed the installation steps and then I picked several plugins to install during the installation steps. When Jenkins is running and I have finnished nstalling all plugins (don’t forget the “configuration-as-code” plugin), I went to “manage” and then clicked on “Script Console“. There you see an textfield to execute groovy scripts and I used the following script:

def plugins = jenkins.model.Jenkins.instance.getPluginManager().getPlugins()
plugins.each {println "${it.getShortName()}:latest"}

This is a “script” that provides an overview of all plugins that are currenlty installed in Jenkins. I have used the “latest” version of the plugin which is fine for demo purposes, but you could also update the “latest” to ${it.getVersion()}. This will show the actual version of the installed plugin. I would suggest to use the versions in the plugins.txt file. This helps you in the future when someone create’s an PR that it shows you that there is an update in the version of a plugin, which you won’t see when it is using “latest”.

Then you hit the “Run” button and you will see some output appear. Select the output and place that in the plugins.txt file and you are done (I would also sort the contents of the file, so all plugins are order alphabetical).

Configuration as code

Let us first explain how we can get a yaml file. Go to “Manage” and then you will see “Configuration as Code” (And click on it please) in the “System Configuration” lane. There is a button called “Download Configuration” which will download the yaml file and with “View Configuration” you can see the yaml file in your browser. When you have downloaded the yaml configuration file, you can make use of it in your Docker image by placing it in the casc/ directory. I would suggest you split it into seperate files, so you won’t have 1 large file but smaller ones with each a specific set of configuration. For example, create a credentials.yaml file containing all Jenkins credentials. 

But before you commit all your changes, you can also update some values by using environment variables, see the following:

  securityRealm:
    local:
      allowsSignup: false
      enableCaptcha: false
      users:
      - id: "${JENKINS_ADMIN_USERNAME:-admin}"
        name: "${JENKINS_ADMIN_NAME:-Administrator}"
        password: "${JENKINS_ADMIN_PASSWORD}"

This piece of the configuration you see now is responsible for creating an admin user. I don’t want to hardcode the username and definitely not the password in this file, so I use environment variables for that. And this is also the case for the credentials that Jenkins use, see the following example of the Jenkins “credentials”:

credentials:
  system:
    domainCredentials:
      - credentials:
          - basicSSHUserPrivateKey:
              scope: GLOBAL
              id: "SSH_GIT_KEY"
              username: "git"
              description: "SSH Credentials for jenkins"
              privateKeySource:
                directEntry:
                  privateKey: ${JENKINS_SSH_GIT_KEY}

With the above credential configuration I won’t have to hardcode the SSH Private key in the Docker image, but can use it as an environment variable. Nice right? 🙂

When everything is done via code, we can also already configure the Security Matrix and allowing what user can and most importantly can’t do in Jenkins. As my Jenkins is running on premise and don’t allow traffic from outside the environment, I will allow people to start jobs (if they don’t want to wait on the triggering). So I will allow anonymous people to have read, build and cancel rights for the jobs. Why go for all that trouble for letting people authenticate against some source, so we can see that this person has started or cancelled a job? Most importantly, they can’t change anything unless they know the admin password. (But will be undone when Jenkins is restarted! :))

  authorizationStrategy:
    globalMatrix:
      permissions:
      - "Job/Build:anonymous"
      - "Job/Cancel:anonymous"
      - "Job/Read:anonymous"
      - "Overall/Administer:admin"
      - "Overall/Read:anonymous"

Now we are able to fully do Jenkins as code, as we will store the yaml files in the casc/ directory which are loaded when Jenkins is started. But when Jenkins is running, we also need to make sure that we will load the jobs from somewhere. We will do this with a “Seed Job“, which you can see in the “dsl-jobs.yaml” file in the casc/ directory in the Github repository.

            git {
                remote { 
                    url "${JENKINS_JOB_DSL_URL}"
                    credentials 'SSH_GIT_KEY' 
                }
                branch '*/main'
              }
        }
        triggers {
            scm('H/15 * * * *')
        }
        steps {
          dsl {
            external('${JENKINS_JOB_DSL_PATH:-jobs}/*.groovy')
            removeAction('DELETE')
          }
        }
      }

When Jenkins is started, we will automatically create the “Seed all DSL jobs” Jenkins job. And what it does is basically the following (Snippet is incomplete, see for the compete file on Github for full version):

  1. We use the credential ‘SSH_GIT_KEY‘ to checkout the repository mentioned in ${JENKINS_JOB_DSL_URL} (See the docker-compose.yaml file)
  2. We use the ‘main’ branch;
  3. The job is executed every 15 minutes;
  4. In the directory named ${JENKINS_JOB_DSL_PATH} we will find groovy files and if Jenkins has jobs which aren’t configured in these groovy files, we delete the jobs from Jenkins.

Before we finalise the Configuration as code part, we need to discuss one last file (and action). When we have the Jenkins server running, we will run each job in its own Docker container. So the Jenkins server will start a Docker container and do all of its action inside that container and the configuration is what follows:

jenkins:
  clouds:
    - docker:
        name: "docker"
        dockerApi:
          dockerHost:
            uri: "${DOCKER_HOST:-unix:///var/run/docker.sock}"
        templates:
        - connector:
            attach:
              user: "jenkins"
          dockerTemplateBase:
            bindAllPorts: true
            image: "jenkins/agent:latest"
            privileged: true
            environment:
              - "TZ=Europe/Amsterdam"
          instanceCapStr: "99"
          labelString: "worker"
          name: "worker"
          remoteFs: "/home/jenkins/agent"

This is also seen in the file “docker.yaml“. Here we have placed 1 template which we named “worker“, with the “jenkins/agent:latest” Docker image. As you know, this is just an example so you can modify this to your needs and use a Docker image that suits your needs. This Docker image should contain all the tools needed to run your jobs, so the “jenkins/agent:latest” might not be fit for your setup. And do know, as the “templates” key is a list, you can add a lot more templates with a unique name, settings and Docker image. For the dockerHost.uri, you will see the usage of a environment variable “DOCKER_HOST“. This is an variable we use in docker-compose.yaml file and if we don’t provide one, the default unix:///var/run/docker.sock is used.

You can go to “manage“, “Systems configuration” and scroll all the way down until you will see “Cloud“. It provides a link and when clicking on it, you’ll get the page where you can configure the “Cloud” configuration. When you make changes, don’t forget to export the yaml file on the “Configuration as Code” page mentioned earlier.

Build and ship it

So far we have discussed some basics on how we get our configuration, so lets build a Docker image. During the rest of this blog post, I will assume you will have the same layout as my Github repository. So lets go to the directory where we have the “Dockerfile“, “plugins.txt“, “docker-compose.yaml” file and the “casc/” directory. Here we will run the docker build command, to build the new Docker image.

cd server
docker build -t jenkins-as-code . --pull

I named it ‘jenkins-as-code‘ which works locally fine and if you want to push it into a Docker registry, you should prefix it with the correct registry name. If you prefix it with a registry or you named it differently, don’t forget to update the docker-compose.yml file with your new name. The –pull is there so if you already have a “jenkins/jenkins:lts” Docker image, you will get the latest one.

I think it is build now, otherwise we will wait a minute before we continue.

sleep 60 🙂

Ok, the Docker image is build and we can start it. If you see the docker-compose.yaml file, you will notice 2 ‘services’.

  1. socat;
  2. jenkins (The one will just build and want to start).

But lets describe the ‘socat‘ service. The ‘socat‘ service is used to make sure that our docker.sock file from our host can be used with Jenkins for starting the agents. If we do this from the Jenkins container itself and not using this ‘socat‘ service, we will get permission denied errors and Jenkins can not start any new Docker container (I am doing on a Mac, I don’t think people running it on Linux hosts will have issues ). 

The Jenkins service has several environment variables set. Before we start everything, we will need to create an environment variable first that contains the content of a private SSH key. I have used the following command for that:

export EXPORTED_PASSWORD=$(cat ~/.ssh/wd_id_rsa)

So this EXPORTED_PASSWORD contains the private SSH key and this one will be used in Jenkins as the SSH_GIT_KEY credential on multiple places. Also worth to mention is the JENKINS_ADMIN_PASSWORD environment variable, this is what is says: The password for the Admin user, so if you want to use something else here is the moment to change it.

We will start it with the following command:

docker compose up -d

I prefer starting it in the background, so that is why I added the -d argument. Once it is booted we open our favourite browser and go to http://localhost:8080 you will see something like the following:

So that is it for now. We started our newly build Docker image containing Jenkins, with the plugins we need in our environment and our own configuration!

We will go into the “Seed All DSL jobs” job with the next part of the blogpost. So stay tuned! 🙂

Continuous deployment of Ansible Roles

Ansible Logo

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.

Testing Ansible roles in a cluster setup with Docker and Molecule

ansible_logo_black_square

This page is updated on 2017-05-01.

This is a follow up on the previous 2 blog posts. With the first blog we discussed some steps to test your Ansible role with some basic steps. With the 2nd blog we added some features to extend our test by using CI tooling and group vars. With this post however, we might be configuring Molecule that will not occur very common with testing Ansible roles.

This time we configure Molecule for a role that is installing and configuring a cluster on Docker, like MySQL or MongoDB. We don’t go into a specific role (as there are so many), I only give some information on how to do this. We are only configuring Molecule for this setup, I’m still busy with running some specific TestInfra tests on a specific container.

Keep in mind these actions are only needed when using the {{ ansible_eth0.ipv4.address }} isn’t enough and you need a list with all ips.

For configuring Molecule, we’ll have to change 2 files:

  1. molecule.yml
  2. playbook.yml

molecule.yml

First we update the ‘molecule.yml’ file by configuring 3 (Or more, depends on what you need) docker containers. See the following example:

docker:
  containers:
  - name: node1
    ansible_groups:
      - cluster_service
    image: milcom/centos7-systemd
    image_version: latest
    privileged: True
    port_bindings:
      3306: 3306,
      4444: 4444
  - name: node2
    ansible_groups:
      - cluster_service
    image: milcom/centos7-systemd
    image_version: latest
    privileged: True
    port_bindings:
      3307: 3306,
      4445: 4444
  - name: node3
    ansible_groups:
      - cluster_service
    image: milcom/centos7-systemd
    image_version: latest
    privileged: True
    port_bindings:
      3308: 3306,
      4446: 4444

As you see, I have added the ‘port_bindings’ configuration to the instances, which is different with the examples in the previous blog posts. With the containers, we open the ports on the host (Before the ‘:’) and proxy them to the ports to the docker container (After the ‘:’ ).

In the above example, this ports configuration is used for configuring a MySQL (Or MariaDB) Galera cluster setup. You’ll have to update the ports configuration to your needs.

playbook.yml

Before we specify the roles in the ‘playbook.yml’, we add an ‘pre_tasks’. We add 2 blocks of code and will discuss them one by one. First we add the following in the ‘pre_tasks’ part:

    - name: "Get ip node 1"
      local_action: shell docker inspect --format \{\{.NetworkSettings.IPAddress\}\} node1
      register: node_ip_1
      changed_when: False
    - name: "Get ip node 2"
      local_action: shell docker inspect --format \{\{.NetworkSettings.IPAddress\}\}  node2
      register: node_ip_2
      changed_when: False
    - name: "Get ip node 3"
      local_action: shell docker inspect --format \{\{.NetworkSettings.IPAddress\}\}  node3
      register: node_ip_3
      changed_when: False

We have added 3 tasks, that do the same command but for each container. We execute a ‘docker inspect’ command to get the ip address of the docker container. As the docker inspect command used the ‘{{ .NetworkSettings.IPAddress }}’ format, Ansible will try to replace it because it thinks it is a variable. Luckily, we can make use of ‘{{ raw }} {{ endraw }}’ for this and Ansible will not use this as a variable anymore.

We register a variable, because we need to use the output, because the ‘docker inspect’ outputs the ip address. We also have to add the property ‘changed_when: False’.

What do you mean with the last one?

We have to fool Ansible with the ‘changed_when’ command for the ‘idempotence’ check. As this task will run every time, the ‘idempotence’ check will fail because of it (because it sees that there are tasks with state “Changed”).

Now we add the 2nd block of tasks to the ‘pre_tasks’, just after the first block of code we added earlier:

    - name: "Set fact"
      set_fact:
        node_ip: "{{ node_ip_1.stdout }}"
      when: inventory_hostname  == 'node1'
    - name: "Set fact"
      set_fact:
        node_ip: "{{ node_ip_2.stdout }}"
      when: inventory_hostname  == 'node2'
    - name: "Set fact"
      set_fact:
        node_ip: "{{ node_ip_3.stdout }}"
      when: inventory_hostname  == 'node3'

With this block we add 3 tasks again, 1 task for each container, to create a fact. In this case, I used to create the fact with the name ‘node_ip’, but you may name it differently. In my case when I use the ‘node_ip’ in my Ansible role, it get the actual IP of the host.

You can also create a list with all the ips if you need this in your role:

cluster_host_ips:
  - "{{ node_ip_1.stdout }}"
  - "{{ node_ip_2.stdout }}"
  - "{{ node_ip_3.stdout }}"

(You have to use the corrent name for the list of course 😉 )

I don’t know if this is the correct way, but it works in my case. I have a Jenkins job that validates a role that is configured to run a 3 node setup (Elasticsearch, MariaDB and some others).

If you have a other or a better way for doing this, please let me know!

Extending Ansible Role testing with Molecule by adding group_vars, dependencies and using travis ci

ansible_logo_black_square

This blog post will extend the actions we described on this https://werner-dijkerman.nl/2016/07/10/testing-ansible-roles-with-molecule-testinfra-and-docker/ page. We only configured a very basic configuration with 2 tests in the previously mentioned page, but thats not enough to and on this page we will continue to complete the tests. Github page for Molecule (In case you forgot 😉 )

We will discuss the following in this blogpost:

  • Make the TestInfra tests OS aware
  • Use group_vars
  • Role dependencies
  • Configure Travis

Lets dive into the tasks.

TestInfra OS Aware

Ok, not really molecule related, but very important if our role needs to work on several different operating systems. In the earlier mentioned blogpost we had configured Molecule to use a Ubuntu docker image. Before we can make the tests OS aware, we have to add some docker containers to the configuration which have different operating systems.

We create the following configuration:

docker:
  containers:
  - name: zabbix-agent-centos
    ansible_groups:
      - group1
    image: milcom/centos7-systemd
    image_version: latest
    privileged: True
  - name: zabbix-agent-debian
    ansible_groups:
      - group2
    image: maint/debian-systemd
    image_version: latest
    privileged: True
  - name: zabbix-agent-ubuntu
    ansible_groups:
      - group2
    image: rastasheep/ubuntu-sshd
    image_version: latest
    privileged: True

We have 3 docker containers configured: Ubuntu, Debian and CentOS. I’ve searched for Docker containers that have systemd configured, as the Zabbix Agent uses this. The official docker images of the mentioned OS’es doesn’t have the systemd enabled/configured.

We would like to run the ‘molecule test’ command, but it will fail on the ‘verify’ part.
We currently have this test:

def test_zabbix_package(Package, SystemInfo):
    zabbixagent = Package('zabbix-agent')
    assert zabbixagent.is_installed

    assert zabbixagent.version.startswith("3.0")

This test will validate if Zabbix is installed and the version starts with 3.0 (Thats the default version to be installed). When running this test, it will fail on the Debian and Ubuntu host. Why?They use a slightly different version naming than CentOS.

We have to update the function by adding the SystemInfo class to the function:

def test_zabbix_package(Package, SystemInfo):
    zabbixagent = Package('zabbix-agent')
    assert zabbixagent.is_installed

    if SystemInfo.distribution == 'debian':
        assert zabbixagent.version.startswith("1:3.0")
    if SystemInfo.distribution == 'centos':
        assert zabbixagent.version.startswith("3.0")

Now we have added the SystemInfo class to the function, we can use this to determine which tests we can execute on which OS. In the above example we see that if the distribution ‘debian’ is, we validate if the version starts with ‘1:3.0’. With CentOS we validate if it is ‘3.0’. When we execute the test on all 3 hosts, it will run successfully.

Using group_vars

This part also applies to using ‘host_vars’, just replace the word ‘group_vars’ with ‘host_vars’ 😉 We configure the molecule.yml file by adding some group_vars related data. We configure the 1st block in the molecule.yml like this:

ansible:
  playbook: playbook.yml
  group_vars:
    mysql:
      database_type: mysql
      database_type_long: mysql
    postgresql:
      database_type: pgsql
      database_type_long: postgresql
      postgresql_pg_hba_conf:
        - "host all all 127.0.0.1/32 trust"
        - "host all all ::1/128 trust"
      postgresql_pg_hba_local_ipv4: false
      postgresql_pg_hba_local_ipv6: false

This setup will “create” 2 group_var files: mysql and postgresql. When we run a molecule command, the group_vars will be created in the .molecule directory. Lets run a ‘molecule list’ command. For know we ignore the output, but lets see what is created in the .molecule directory:

[vagrant@localhost ansible-zabbix-server]$ find .molecule -type f | xargs ls -lrt
-rw-rw-r--. 1 501 games   3 Jul 17 20:31 .molecule/state
-rw-rw-r--. 1 501 games 215 Jul 17 20:31 .molecule/group_vars/postgresql
-rw-rw-r--. 1 501 games  51 Jul 17 20:31 .molecule/group_vars/mysql
[vagrant@localhost ansible-zabbix-server]$ cat .molecule/group_vars/mysql
---
database_type: mysql
database_type_long: mysql
[vagrant@localhost ansible-zabbix-server]$ cat .molecule/group_vars/postgresql
---
database_type: pgsql
database_type_long: postgresql
postgresql_pg_hba_conf:
- host all all 127.0.0.1/32 trust
- host all all ::1/128 trust
postgresql_pg_hba_local_ipv4: false
postgresql_pg_hba_local_ipv6: false

Within the .molecule directory a group_vars directory is created and 2 files are present (We will ignore the ‘state’ file). The output of these files are the same as how we configured the molecule.yml file.

Role dependencies

When your role has some dependencies, we really want them to download before we execute our role in Molecule. It will fail if we don’t do this. We have to download them first.

Molecule has a simple configuration for this. Within the molecule.yml file, we add the ‘requirements_file’ option in the Ansible configuration. Our example now looks like this:


dependency:
  name: galaxy
  requirements_file: requirements.yml 
  options:
    ignore-certs: True
    ignore-errors: True

ansible:
  playbook: playbook.yml
  group_vars:
    mysql:
      database_type: mysql
      database_type_long: mysql
    postgresql:
      database_type: pgsql
      database_type_long: postgresql
      postgresql_pg_hba_conf:
        - "host all all 127.0.0.1/32 trust"
        - "host all all ::1/128 trust"
      postgresql_pg_hba_local_ipv4: false
      postgresql_pg_hba_local_ipv6: false

In the root directory of the repository, a file called ‘requirements.yml’ is found which contains the dependencies.

When we run the ‘converge’ subcommand, the roles will be downloaded and after this the role is executed:

[vagrant@localhost ansible-zabbix-server]$ molecule converge
WARNING:vagrant:The Vagrant executable cannot be found. Please check if it is in the system path.
--> Installing role dependencies ...
- downloading role 'apache', owned by geerlingguy
- downloading role from https://github.com/geerlingguy/ansible-role-apache/archive/1.7.2.tar.gz
- extracting geerlingguy.apache to .molecule/roles/geerlingguy.apache
- geerlingguy.apache was installed successfully
- downloading role 'mysql', owned by geerlingguy
- downloading role from https://github.com/geerlingguy/ansible-role-mysql/archive/2.3.0.tar.gz
- extracting geerlingguy.mysql to .molecule/roles/geerlingguy.mysql
- geerlingguy.mysql was installed successfully
- downloading role 'postgresql', owned by galaxyprojectdotorg
- downloading role from https://github.com/galaxyproject/ansible-postgresql/archive/0.9.2.tar.gz
- extracting galaxyprojectdotorg.postgresql to .molecule/roles/galaxyprojectdotorg.postgresql
- galaxyprojectdotorg.postgresql was installed successfully
--> Starting Ansible Run ...

PLAY [all] *********************************************************************

TASK [setup] *******************************************************************
ok: [zabbix-server-centos-mysql]
... 
<snip>

Configure CI

We don’t want to run manually the molecule commands every time a change occurs. To quote Apple: “There is an app for that”. Well almost. I explain 2 ways of running Molecule in a automated way: Using Travis and Using Jenkins.

Travis

A commonly known cloud platform for CI, and it is very simple to make use of it. The Molecule documentation has a very nice example on how to configure the travis setup. We create in the root directory of our role, a file named: .travis.yml

sudo: required
language: python
services:
- docker

before_install:
- sudo apt-get -qq update
- sudo apt-get install -o Dpkg::Options::="--force-confold" --force-yes -y docker-engine

install:
- pip install molecule ansible docker

script:
- molecule test
notifications:
  webhooks: https://galaxy.ansible.com/api/v1/notifications/

Its a very basic travis configuration. First block is to let Travis know that we need to make use of sudo, that the language Python is and we use the ‘docker’ service.

2nd block is to update the Ubuntu’s apt cache and install Docker. When Docker is installed, we install molecule and after that, molecule test is executed. When the job is finished, we send some data via a web hook to the Ansible Galaxy page. The last step is to show the ‘passing’ (Or failing) badge on the Ansible Role page.

Jenkins

This example will show you a basic Jenkinsfile. I don’t do a single action manually in Jenkins. A  Jenkins job is basically code and we should use it as code. With Jenkins 2, we can make use of a Jenkinsfile (Also with Jenkins 1, but was named jenkins-template I believe?)

When you have a Jenkins server running, create a new Pipeline job and configure the correct git repository. (Okay, for this blogpost we do this manually, but I have a playbook for this. So this is on my part automated as well. 😉 )

A basic example:

node(){
    stage 'INFO: Checkout code'
        checkout scm
    stage 'Installing Molecule'
        sh 'sudo pip install molecule'
    stage 'Creating Containers'
        sh 'molecule create'
    stage 'Installing the Role'
        sh 'molecule converge'
    stage 'Idempotence check'
        sh 'molecule idempotence'
    stage 'Verify the application'
        sh 'molecule verify'
    stage 'Destroy the containers'
        sh 'molecule destroy'
}

When the job is executed, it will first download the Jenkinsfile from the configured git repository and the tasks will be executed one by one. This is just to get you started and the Jenkinsfile should be extended with some error handling like e-mail configuration etc.

So this was the follow up on the original blogpost for how to use Molecule with your Ansible role. The guys are really busy with Molecule so Molecule grows really fast. Maybe doing an 3rd blogpost very soon with new features.. 🙂

Testing Ansible roles with Molecule, Testinfra and Docker

ansible_logo_black_square

“On 2017-05-01 I’ve updated this post to the current situation. Some things where outdated and where removed.”

In some earlier posts I’ve described how you can use Test Kitchen for testing Ansible Roles (This one and the one extending it.). Test Kitchen was created for testing Chef Cookbooks and like Chef, Test Kitchen is a Ruby application. On this page we describe an other tool for the same purpose. This tool is what you might see as a Python clone of Test Kitchen, but more specific to Ansible: Molecule (Github)

Molecule isn’t that old, only few years and when I browse the internet it is not yet really known in the community. Unlike Test kitchen with the many different drivers, Molecule supports several backends, like Vagrant, Docker, and OpenStack. With Molecule you can make use of Serverspec (Like Test Kitchen), but you can also make use of ‘Testinfra’. Testinfra is like Serverspec a tool for writing unit tests, but it is written in Python.

Lets dive into Molecule and create some tests for Molecule. On this page, we make use of the Docker backend and if you following this page please install docker.

Installing Molecule is really simple:

pip install molecule docker

Voila, it is installed. With the installation of Molecule, Testinfra is installed to. We had to provide the docker module as well, otherwise molecule doesn’t know how to connect to the docker daemon. We can configure a Ansible Role. I used my ‘zabbix-agent’ role as test case for the Test Kitchen setup, so I will use it again for Molecule.

When you haven’t created an Ansible role yet, instead of using the ansible-galaxy command you can use the following command:

molecule init --driver docker --role role_name

This will create just like the ‘ansible-galaxy’ some default directories and files, but also gives us a starting point with a few extra files for testing this role with Molecule.

When you already have a working module and want to make use of Molecule, please execute the following command:

molecule init --driver docker

This will install several files specific for Molecule. No worries, we can recreate these files manually. Lets do that in a role and see what the files do.

File: <root>/molecule.yml

---
ansible:
  playbook: playbook.yml

driver:
  docker
docker:
  containers:
    - name: zabbix-01
      ansible_groups:
        - group1
      image: debian
      image_version: latest
      privileged: True

verifier:
  name: testinfra

This is the configuration file for Molecule. We specify which playbook Molecule will execute, in this case playbook.yml.
We specify that we want to make use of the Docker driver and that we have a docker container configuration. In this case, we only have 1 docker container specified. We use a Debian docker container with the ‘latest’ tag. We name the container ‘test-01’ and is in the group ‘group1’. And at last we configure molecule to use testinfra as the testtool.

File: <root>/playbook.yml

---
- hosts: all
  roles:
    - role: ansible-zabbix-agent

The playbook that is executed in the Docker container. This is a very basic one, we only have to specify the correct .

File: <root>/tests/inventory

localhost
[group1]
zabbix-01 ansible_connection=docker

The Ansible inventory file. Should be a known file to you 😉

File: <root>/tests/test_default.py


from testinfra.utils.ansible_runner import AnsibleRunner
testinfra_hosts = AnsibleRunner('.molecule/ansible_inventory').get_hosts('all')

def test_hosts_file(File):
    hosts = File('/etc/hosts')
    assert hosts.user == 'root'
    assert hosts.group == 'root' 

(Edit 2016-09-14: As of release 1.9, the first 2 lines should be present in the TestInfra script.)

This is the test infra python file, containing the tests. After the init command, we have 1 test that will check if there is a hosts file, and the user and group of the file belongs to user ‘root’. We discuss this file later on by adding some more tests.

File: <root>/tests/test.yml

---
- hosts: localhost
  remote_user: root
  roles:
    - zabbix-agent-role

Now we have discussed the files.

We add some infra test checks in the ‘test_default.py’ file. We add the following 2 tests:

def test_zabbix_package(Package):
    zabbixagent = Package('zabbix-agent')
    assert zabbixagent.is_installed
    assert zabbixagent.version.startswith("1:3.0")

def test_zabbixagent_running_and_enabled(Service):
    zabbixagent = Service("zabbix-agent")
    # assert zabbixagent.is_running
    assert zabbixagent.is_enabled

These are 2 Python function which are executed with Testinfra. With the first function, we validate if the package ‘zabbix-agent’ is installed. Also we check if the version starts with: 1:3.0. If you have some experience with testing Python code, this might be familiar to you. Test Infra uses ‘PyTest‘ to execute the tests and validate the.

The 2nd function we validate the ‘zabbix-agent’ service. We make sure the service is enabled. As you see, I’ve commented the check if the service is running. When it is enabled, I get this error message:

Failed to get D-Bus connection: Unknown error -1

Strange, because I’ve configured the privileged mode on the docker container. So maybe this is a bug or misconfiguration on my part, but for now I leave it commented and need to find a solution for this.

Within the molecule.yml we have to update the docker container configuration by adding the following property for all the docker containers:

    required: True

Now we added it, we have to do a “molecule destroy” and start again. The container will be recreated and we won’t get an error message about the dbus.

Now we are ready to move on (I’m well aware that these 2 tests that I added will not be enough, I’ll add these myself later on).

Molecule has several subcommands, let run molecule -h and see what is available:

No handlers could be found for logger "vagrant"
Usage:
    molecule [-hv] &amp;amp;lt;command&amp;amp;gt; [&amp;amp;lt;args&amp;amp;gt;...]

Commands:
    check         check playbook syntax
    create        create instances
    converge      create and provision instances
    idempotence   converge and check the output for changes
    test          run a full test cycle: destroy, create, converge, idempotency-check, verify and destroy instances
    verify        create, provision and test instances
    destroy       destroy instances
    status        show status of instances
    list          show available platforms, providers
    login         connects to instance via SSH
    init          creates the directory structure and files for a new Ansible role compatible with molecule

Options:
    -h --help     shows this screen
    -v --version  shows the version

We first start with the ‘check’ command:

[vagrant@localhost ansible-zabbix-agent]$ molecule check
No handlers could be found for logger "vagrant"

playbook: playbook.yml
[vagrant@localhost ansible-zabbix-agent]$ echo $?
0

Seems very well, the check commands validate if the playbook.yml doesn’t have any problems/syntax errors.
We can continue with the next command: create.

[vagrant@localhost ansible-zabbix-agent]$ molecule create
No handlers could be found for logger "vagrant"
 Building ansible compatible image ...
 Step 1 : FROM debian:latest

  ---&amp;amp;gt; 1b088884749b

 Step 2 : RUN bash -c 'if [ -x "$(command -v apt-get)" ]; then apt-get update &amp;amp;amp;&amp;amp;amp; apt-get install -y python sudo; fi'

  ---&amp;amp;gt; Using cache

  ---&amp;amp;gt; 8ef54383599a

 Step 3 : RUN bash -c 'if [ -x "$(command -v yum)" ]; then yum makecache fast &amp;amp;amp;&amp;amp;amp; yum update -y &amp;amp;amp;&amp;amp;amp; yum install -y python sudo; fi'

  ---&amp;amp;gt; Running in 6d3142fa72aa

...
 Finished building molecule_local/debian:latest
 Creating container zabbix-01 with base image debian:latest ...
 Container created.

[vagrant@localhost ansible-zabbix-agent]$

Now we have created a docker container where we can install our Ansible role on to, we do that with the ‘converge’ subcommand.

[vagrant@localhost ansible-zabbix-agent]$ molecule converge
No handlers could be found for logger "vagrant"

PLAY [all] *********************************************************************

TASK [setup] *******************************************************************
ok: [zabbix-01]

TASK [ansible-zabbix-agent : Include OS-specific variables] ********************
ok: [zabbix-01]

TASK [ansible-zabbix-agent : Install the correct repository] *******************
skipping: [zabbix-01]

...
RUNNING HANDLER [ansible-zabbix-agent : restart zabbix-agent] ******************
changed: [zabbix-01]

PLAY RECAP *********************************************************************
zabbix-01                  : ok=12  changed=7    unreachable=0    failed=0

Nice, the role is installed correctly without any issues on the container. With Test Kitchen we had to use BATS to validate if the Role is idempotent, but luckily molecule has just a simple sub command for it: idempotence

Well, it seems that the Role has passed the idempotence test:

[vagrant@localhost ansible-zabbix-agent]$ molecule idempotence
No handlers could be found for logger "vagrant"
Idempotence test in progress (can take a few minutes)...
Idempotence test passed.

[vagrant@localhost ansible-zabbix-agent]$

Testing the role is nicely going on right now, but we are not there yet. Now we need to use the ‘verify’ command to actually validate our role on the Docker container:

[vagrant@localhost ansible-zabbix-agent]$ molecule verify
No handlers could be found for logger "vagrant"
Trailing whitespace found in ./defaults/main.yml on lines: 35
Trailing newline found at the end of ./handlers/main.yml
Trailing whitespace found in ./library/zabbix_host.py on lines: 29
Trailing newline found at the end of ./library/zabbix_hostmacro.py
[vagrant@localhost ansible-zabbix-agent]$

Whoops, it seems it has found some issues. Let me fix that first, probably need to run the verify again after fixing it.

[vagrant@localhost ansible-zabbix-agent]$ molecule verify
No handlers could be found for logger "vagrant"

Executing testinfra tests found in tests/.
============================= test session starts ==============================
platform linux2 -- Python 2.7.5, pytest-2.9.2, py-1.4.31, pluggy-0.3.1
rootdir: /git/ansible/ansible-zabbix-agent/tests, inifile:
plugins: xdist-1.14, testinfra-1.4.0
collected 3 itemss

tests/test_default.py ...

=========================== 3 passed in 0.63 seconds ===========================

No serverspec tests found in spec/.

[vagrant@localhost ansible-zabbix-agent]$

After fixing it, everything seems to work fine. Nice!

Now we are done with the container, so we can execute molecule again, but with the delete sub command and the container will be deleted.

These were the basics for testing an Ansible role with Molecule, Docker and Test Infra. This page uses the ‘Debian’ Docker image, whereas I normally use CentOS for this. I have some issues (Get the same error message when I enable the Test Infra test to validate if the service is running) to make this work on CentOS. So maybe Molecule isn’t mature enough yet, but it is getting there.

I’ll update my Ansible roles so it will use Molecule instead of Test Kitchen (No hard feelings ;-))