Ansible
Redbrick uses ansible to manage its infrastructure. This document describes the procedures and some tips to get the most out of it.
Getting started
Installing ansible
Ansible is a python package, so you'll need to install python first. On Debian/Ubuntu, you can do this with:
pip install ansible
Add an SSH key
Ansible uses ssh to connect to the remote hosts. You'll need to set up your ssh key so that you can connect to the hosts without constant prompts for passwords.
Create a hosts file
This is used a phonebook of sorts for ansible. It tells ansible which hosts to connect to, and what user to use.
[aperture]
glados
wheatley
chell
[aperture:vars]
ansible_user= <your username>
Contact @distro for a fully populated file.
Test it out
ansible all -m ping
This should connect to all the hosts in the aperture group, and run the ping module. If it works, you're good to go!
Playbooks
Ansible playbooks are a set of instructions for ansible to run. They're written in YAML, and are usually stored in a file
called playbook.yml.
Writing a playbook
Ansible playbooks are written in YAML. The basic structure is:
- hosts: <group name>
tasks:
- name: <task name>
<module name>:
<module options>
Example
- hosts: aperture
tasks:
- name: Install curl
apt:
name: curl
state: present
This playbook will connect to all the hosts in the aperture group, and run the apt module with the name and state
options.
Running a playbook
ansible-playbook playbook.yml -i hosts
More Information
Redbrick's ansible configuration is stored in the ansible repository. There's some more documentation there on each playbook.
Ansible's documentation is available here.
Common Errors
Hashicorp Apt Key
Sometimes, when running a playbook, you'll get an error like this:
TASK [apt : apt update packages to their latest version and autoclean] ***************************************************************************************************
fatal: [wheatley]: FAILED! => {"changed": false, "msg": "Failed to update apt cache: unknown reason"}
fatal: [chell]: FAILED! => {"changed": false, "msg": "Failed to update apt cache: unknown reason"}
fatal: [glados]: FAILED! => {"changed": false, "msg": "Failed to update apt cache: unknown reason"}
This is because the Hashicorp apt key has expired. To fix this, uncomment the hashicorp-apt task in the playbook.