Ansible/Playbooks
From charlesreid1
Overview
The Ansible documentation has a nice overview of playbooks: https://docs.ansible.com/ansible/latest/user_guide/playbooks_intro.html
Notes on playbooks:
- playbooks are a way of executing commands on remote machines in a scripted way
- can orchestrate multiple ordered processes
- playbooks are written in YAML
- each playbook can contain one or more plays
- each play will target different servers (maybe all of them, maybe just web servers, maybe just db servers)
- user specifies hosts - remote machines on which Ansible will run commands
- users - the remote user is the user that Ansible will run the particular task as
Notes on tasks:
- each play has a list of tasks associated with it
- tasks are executed in order on all machines that match the host pattern
- ansible completes the task on all remote machines before it moves on to the next task
Notes on handlers:
- the handlers are triggered once at the end of each block of tasks - this keeps them from being restarted over and over by a set of related tasks
Notes on being idempotent:
- idempotent means you can run it multiple times with the same outcome as running it one time
- modules should check whether the desired final state has already been achieved, and exit without doing anything if so
Example: Secure Nginx Server
Ansible/Nginx Playbook - a page that walks through two example playbooks
Full Stack Example: Django Celery RabbitMQ Postgres
Ansible/Full Stack Playbook - a page that walks through a playbook for a full stack example
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