4. Roles

4.1. Ansible Roles

Ansible Roles are special kind of Playbook that are fully self-contained with:

4.2. Ansible Galaxy

  • Repository of user defined Roles

4.3. Example

- name: "Installing packages"
  package: name={{item}} state=installed
  - gunicorn
  - supervisor
  - python-mysqldb
  - python-falcon

- name: "Making sure supervisor is enabled and started"
  service: name=supervisor state=started enabled=yes

- name: "Creating the base folder of the application"
  file: path=/opt/myapp state=directory owner=nobody group=nobody mode=0755

- name: "Copying the application"
  copy: src=../myapp.py dest=/opt/myapp/myapp.py owner=nobody group=nobody mode=0755
  - restart-app

- name: "Copying the supervisor config file"
  template: src=../files/myapp.conf dest=/etc/supervisor/conf.d/myapp.conf owner=nobody group=nobody mode=0644
  - reload-config
  - restart-app

- name: "Adding IP od dbserver to /etc/hosts"
  lineinfile: name=/etc/hosts line="{{ hostvars['dbserver']['ansible_eth0']['ipv4']['address'] }} dbserver"

- name: reload-config
  shell: supervisorctl reread
- name: restart-app
  supervisorctl: name=myapp state=restarted

4.4. Best Practices

  • Keep roles purpose and function focus

  • Used a roles/ subdirectory for roles developed for organizational clarity in a single project

  • Follow the Ansible Galaxy pattern for roles that are to be shared beyond a single project

  • Start your roles with ansible-galaxy init (it will generate directory structure)

  • Remove unneeded directories and stub files (after ansible-galaxy init)

  • ansible-galaxy can point to your internal private repo

  • Use ansible-galaxy to install your roles -- even private ones

  • Manage your roles in your applications repo

  • As a part of build process, "push" role to artifact repository

  • Use ansible-galaxy to install role from artifact repository