Jenkins Job DSL create Seed Job with Configuration as a Cod Plugin

Question

My task is to sping up Jenkins and have Job DSL Seed job automatically created during installation. That means I have to use Configuration as a Code plugin, but this plugin use Job DSL to create jobs, that means I have to create Job DSL job using Job DSL job, did anyone tried this before? Is it nearly possible?

Possible option would be import seed job as XML but this functionality been deprecated in latest Jenkins helm chart.

Answer 1

Yes, it is totally possible.

but this plugin use Job DSL to create jobs - yes, but it assumes, that Job DSL plugin has already been installed.

Let me copy a snippet of deployment of Jenkins that I use:

- name: Get tag of the latest version of Plugin installation manager tool
  ansible.builtin.raw: |
    git ls-remote https://github.com/jenkinsci/plugin-installation-manager-tool.git \
    | grep -E "refs/tags/[0-9]+\.[0-9]+\.[0-9]+$" | tail -n1 | cut -d / -f 3
  register: plugin_manager_version

# https://github.com/jenkinsci/plugin-installation-manager-tool#getting-started
- name: Download Plugin installation manager tool
  ansible.builtin.get_url:
    url:
      "https://github.com/jenkinsci/plugin-installation-manager-tool/releases/\
      download/{{ plugin_manager_version.stdout | trim }}/jenkins-plugin-manager-{{ plugin_manager_version.stdout | trim }}.jar"
    dest: /tmp/jenkins/jenkins-plugin-manager.jar

- name: Copy a list of plugins to install
  ansible.builtin.copy:
    src: plugins.txt
    dest: /tmp/jenkins/plugins.txt
    mode: 0444
    owner: jenkins
    group: jenkins

- name: Install the latest version of plugins
  ansible.builtin.command: |
    java -jar /tmp/jenkins/jenkins-plugin-manager.jar --war /usr/lib/jenkins/jenkins.war -f /tmp/jenkins/plugins.txt -d /var/lib/jenkins/plugins

- name: Set ownership of plugins
  ansible.builtin.file:
    path: /var/lib/jenkins/plugins
    owner: jenkins
    group: jenkins
    mode: 0644
    recurse: true

- name: Set ownership of plugins folder
  ansible.builtin.file:
    path: /var/lib/jenkins/plugins
    owner: jenkins
    group: jenkins
    mode: 0755
    recurse: false

- name: Copy Jenkins configuration files
  ansible.builtin.template:
    src: "{{ item }}.yaml.j2"
    dest: "/var/lib/jenkins/casc_configs/{{ item }}.yaml"
    mode: 0644
    owner: jenkins
    group: jenkins
  loop: "{{ ['credentials', 'general', 'seed-job', 'users'] | flatten(1) }}"

- name: Restart Jenkins
  ansible.builtin.systemd:
    name: jenkins
    state: restarted
    enabled: true

In plugins.txt there are, among others, plugins configuration-as-code and job-dsl.

And seed-job.yaml looks like this:

jobs:
  - script: >
      freeStyleJob('Seed Job') {
          description('Synchronizes Jenkins jobs with ones in my-repo/jobs folder.')
          displayName('Seed Job')
          scm {
              git {
                  remote {
                      name('Jenkins jobs')
                      url('https://github.com/my-repo.git')
                      credentials('GITHUB_CREDENTIALS')
                  }
                  branch('master')
              }
          }
          triggers {
              pollSCM {
                  scmpoll_spec('* * * * *')
              }
          }
          steps {
              dsl {
                  external "jobs/**/*.groovy"
                  removeAction("DELETE")
                  removeViewAction("DELETE")
              }
          }
      }

And now the seed job will automatically import all the jobs from your repository.

An example Job DSL looks like this:

freeStyleJob('System Cleanup') {
    displayName('System Cleanup')
    description('Remove unused Docker stuff and golang cache once a month.')
    label('continuous-integration')
    triggers {
        scm('H 0 1 * *')
    }
    steps {
        shell('docker system prune --all --volumes --force')
        shell('go clean -cache -modcache -testcache')
    }
}

but of course you can write Job DSLs for other types of jobs (e.g. multibranchPipeline). Refer to the API Viewer in your Jenkins instance.