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Example_Ansible.md

Example_Ansible.md

 
 

Example_Bash.md

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Readme.md

Intro to Ansible

This introduction to Ansible is based on my personal experiences.

I will not compare Ansible to other automation tools/frameworks! There may be some out there that can replace Ansible - but I haven't got much experience using other ones.

Sources

What is Ansible

Ansible is used to automate IT administration.

Its base-product is Open-Source and free to use.

There is also an Open-Source web-based control-environment named 'Ansible AWX'.

For enterprise-use RedHat offers a product named 'Ansible Automation Platform' that is Closed-Source and must be licensed.

Key points

Practical examples of use-cases are:

Why automate?

  • Scalability
  • Allows you to implement Infrastructure-as-Code
    • Benefits:
      • Cost reduction
      • Increase in speed of deployments
      • Reduce errors
      • Improve infrastructure consistency
      • Having the configuration of all your IT-systems in one place and versioning it using a Version Control System like Git
  • Abstract the complexity of administration to a single click or button press
  • Simplifying/empowering Continuous integration/Continuous delivery
  • Testing of your automation can also be automated - see: Molecule
    • Making system-upgrades easier
    • Finding and correcting bugs before they hit your actual infrastructure

It is designed to:

  • work in an agentless manner
    • need few to none requirements on the target systems
  • operations being idempotent (checking if operations need to be performed before executing them)
  • combine variable host- & group-configuration with templated tasks
  • verify the target state is as desired

Target systems

What systems can Ansible target?

Third party contributions

There are also third-party community modules that allow you to manage even more systems!

Per example:

Connection types

For Ansible to manage its target system it needs to connect to them.

Most of the time one will use the system-specific default connection-types:

RedHat - Ansible

Advanced tricks

There are also some advanced tricks you can use for connecting to target systems:

Scripting vs Automation

If you have got some experience administrating IT-systems you might think:

Why use a large framework like Ansible if I can just script it? Ansible has much more overhead and is slower than basic bash/powershell scripts..

It's true - Ansible has more overhead and is slower than scripting.

But that has its reasons.

Features

Ansible provides many features that help you prevent mistakes and/or errors:

  • Simplicity:
    • Ansible 'scripts' are written in YAML Syntax. This format makes it really easy to read tasks/roles/playbooks and understand what is going on.
    • Even people without a background in programming or advanced-scripting are able to understand and write most tasks.
  • Check-Mode:
    • Ansible Modules can be executed in check-mode to show you what WOULD BE changed without actually applying those changes.
    • That is pretty useful if you want to test some new functionality or just want to make sure nothing will break.
  • Diff-Mode:
    • Most Ansible Modules have implemented the 'difference' flag/mode - it enables you to see what exact changes are applied.
    • This feature is really useful in check-mode.
    • If the execution did unintentionally break something it helps you to analyze what went wrong.
  • Error handling:
    • Ansible give you many options to configure error-handling.
    • Most Ansible Modules will return useful information whenever they fail just in case you want to soft-handle its failure.
  • Validation
  • Secrets
    • Ansible has a feature named Ansible-Vault that provides a way to encrypt and manage sensitive data such as passwords.
    • You can also use centralized 3th-party vault-solutions like Hashicorp Vault.
    • Sensitive data can also be protected from being logged in clear-text using the 'no_log' parameter. Most Modules also implement this for secrets you pass to them.
    • Secrets that are prompted at runtime can also be encrypted.
  • Configuration
    • Working with complex configurations that require multiple scopes (host, group, role, execution, ...) can be challenging when using raw scripting. Ansible handles much of the mind-boggling logic in the background so we as admins/users don't have to deal with it.

Example

In the following example I will show you the difference between Bash-scripting and Ansible.

Info

What will be configured in this example:

  • Installing web-application dependencies
    • MariaDB database server
    • Apache2 webserver
  • Configuration
    • Apache2
      • Modules
      • Virtualhost
    • MariaDB
      • Config
      • Import database schema
      • Users
    • Copy/update web application
    • Systemd Timer to update some data on a schedule

Compare the Bash and Ansible example and think about it: which one would you rather maintain/work with?

Prerequisites

  • The script and Ansible-playbook needs to be executed on a controller node
  • The controller needs to have network-access to the target-system (ssh port)
  • The executing user needs to be able to
    • connect to the target-system via SSH
    • run commands with root-privileges on the target-system using 'sudo'

Bash

See: Example Bash

Ansible

See: Example Ansible