EX407 Study Guide

This study guide attempts to cover topics for study in the Red Hat EX407 Red Hat Certificate of Expertise in Ansible Automation exam

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Disclaimer

This guide does not divulge any information contained in the test, or style of the objectives. Merely publicly available information based on the wording of the objectives.

Understand core components of Ansible

Inventories

Supply inventory with -i flag with commands

ansible -i inventory -m shell -a “hostname"

Can be set in ansible.cfg

inventory = /etc/ansible/hosts

Static inventory

defined in ini style

[router]
hostname1 ansibe_host=192.168.1.1
[webserver]
hostname2 ansibe_host=192.168.1.2
[database]
hostname3 ansibe_host=192.168.1.3
[appserver]
hostname4 ansible_host=192.168.1.4

Dynamic inventory

returns json

{
  "all": {
    "hosts": [
      "slaves_slave1"
    ]
  },
  "_meta": {
    "hostvars": {
      "slaves_slave1": {
        "ansible_host": "192.168.121.74"
      }
    }
  }
}

Modules

file, stat, lineinfile etc

file module example

Module usage

file: 
  path: /etc/config.cnf
  state: absent

Short hand

file: path=”/etc/config.cnf” state=”absent”

Variables

Variable can be used in inventories, playbooks, roles, defaults

Facts

Hostvars

Setup module to retrieve facts

Debug module to verify facts

Plays

Individual roles

Playbooks

File with a collection of roles/plays

Configuration files

/etc/ansible/ansible.cfg

Run ad-hoc Ansible commands

ansible [groupname] [-i inventory-file] [-m module] [-a arguments]
ansible all -i inventory -m shell -a “hostname”

Use both static and dynamic inventories to define groups of hosts

Static inventory take single hosts by line or ini format

Dynamic inventories return information from outside sources like AWS to gather facts about the inventory

Example for creating dynamic inventories

https://www.jeffgeerling.com/blog/creating-custom-dynamic-inventories-ansible

Utilize an existing dynamic inventory script

./inventory.py {} ./inventory.py --list {"all": {"hosts": ["slaves_slave2", "slaves_slave3", "slaves_slave4", "slaves_slave1", "slaves_slave5"]}, "_meta": {"hostvars": {"slaves_slave5": {"ansible_host": "192.168.121.32"}, "slaves_slave4": {"ansible_host": "192.168.121.29"}, "slaves_slave1": {"ansible_host": "192.168.121.218"}, "slaves_slave3": {"ansible_host": "192.168.121.34"}, "slaves_slave2": {"ansible_host": "192.168.121.119"}}}} ./inventory.py --host { "all": { "hosts": [ "slaves_slave1" ] }, "_meta": { "hostvars": { "slaves_slave1": { "ansible_host": "192.168.121.218" } } } }

Create Ansible plays and playbooks

Know how to work with commonly used Ansible modules

Use variables to retrieve the results of running a commands

Use conditionals to control play execution

Configure error handling

fail module

- fail:
    msg: "The system may not be provisioned according to the CMDB status."
  when: cmdb_status != "to-be-staged"

Create playbooks to configure systems to a specified state

Selectively run specific tasks in playbooks using tags

Create and use templates to create customized configuration files

Work with Ansible variables and facts

Create and work with roles

Download roles from an Ansible Galaxy and use them

Manage parallelism

Use Ansible Vault in playbooks to protect sensitive data

Install Ansible Tower and use it to manage systems

Use provided documentation to look up specific information about Ansible modules and commands

List of modules

Module example