# EX407-Ansible-Automation
Red Hat Certified Specialist in Ansible Automation (EX407) Preparation Course

- [Understanding Core Components of Ansible](#understanding-core-components-of-ansible)
    - [Understanding Core Components of Ansible Part 1](#understanding-core-components-of-ansible-part-1)
    - [Understanding Core Components of Ansible Part 2](#understanding-core-components-of-ansible-part-2)
    - [A Brief Tour of the Ansible Configuration File](#a-brief-tour-of-the-ansible-configuration-file)
    - [LAB Getting Started with Ansible](#lab-getting-started-with-ansible)
- [Run Ad-Hoc Ansible Commands](#run-ad-hoc-ansible-commands)
    - [Run Ad-Hoc Ansible Commands](#run-ad-hoc-ansible-commands)
    - [Demonstration: Ansible Ad-Hoc Commands Part 1](#demonstration-ansible-ad-hoc-commands-part-1)


## Understanding Core Components of Ansible
### Understanding Core Components of Ansible Part 1
This series of lessons lays the foundation for the remainder of the course content. Through a combination of lecture and command line demonstration, Students will gain a broad overview of Ansible. This particular lesson, focuses on Ansible inventories.
  
- Overview
  - Invetories
  - Modules
  - Variables
  - Facts 
  - Plays 
  - Playbooks
  - Configuration files

##### Inventories
![img](https://github.com/Bes0n/EX407-Ansible-Automation/blob/master/images/img1.png)

- Inventory files may simply consist of a list of hostnames but can be much more robust

- It is also possible to define groups of hosts, host or group level variables, and groups of groups withing the inventory

- There are a number of variables that may be used within the inventory to control how ansible connects to and interacts with target hosts

- Commands to call ansible with `ping` module:
    - ```ansible innaghiyev1c.mylabserver.com -m ping -k``` - call ping module on `innaghiyev1c.mylabserver.com` host. Where `-m ping` is ping module
    and `-k` is key for asking password
    - ```ansible all -m ping -k``` - call all defined hosts in your inventory list `/etc/ansible/hosts/`
    - ```ansible -i inv.ini httpd -m ping -k``` - where `-i` - inventory file place, `httpd` hosts group name inside of `inv.ini` file
  
Output:
```
innaghiyev1c.mylabserver.com | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}
```

### Understanding Core Components of Ansible Part 2
This series of lessons lays the foundation for the remainder of the course content. Through a combination of lecture and command line demonstration, Students will gain a broad overview of Ansible. This particular lesson covers the following topics at a very high level: modules, variables, facts, plays, playbooks, and configuration files.
  
- Modules
  - Modules are essentially tools for particular tasks
  - Modules can take (and usually do) take parameters
  - They return JSON
  - Can run from the command line or within a playbook
  - There are a significant number of modules for many kinds of work
  - Custom modules can be written
  
- Variables
  - Variable names should be letters, numbers and underscores
  - Variables should always start with a letter
  - Can be scoped by a group, host, or even ini a playbook
  - Typically used for configuration values and various parameters 
  - Variables can also be used to store the return value of executed commands
  - Ansible variables may also be dictionaries
  - There are a number of predefined variables used by Ansible 
  
- Facts
  - Facts provide certain information about given target host
  - Facts are discovered by Ansible automatically when it reaches out to a host
  - Fact gathering may be disabled
  - Facts may be cached between playbook executions, but this is not default behavior

```
innaghiyev1c.mylabserver.com | SUCCESS => {
    "ansible_facts": {
        "ansible_all_ipv4_addresses": [
            "172.31.37.72"
        ],
        "ansible_all_ipv6_addresses": [
            "2a05:d01c:2c7:d802:4db1:18cc:f13f:a1cf",
            "fe80::9e:19ff:fe1e:7376"
        ],
        "ansible_apparmor": {
            "status": "enabled"
        },
        "ansible_architecture": "x86_64",
        "ansible_bios_date": "10/16/2017",
        "ansible_bios_version": "1.0",
```

- Plays and playbooks
  - The goal of a play is to map a group of hosts to some well-defined roles
  - A play may use one or more modules to achieve a desired end state on a group of hosts
  - A playbook is a series of plays
  - A playbook may deploy new web servers, install a new application to existing application servers, and run SQL against some database servers to support the new application
  
- Configuration Files
  - Several possible locations (in order processed):
    - ANSIBLE_CONFIG (an environment variable)
    - ansible.cfg (in the current directory)
    - .ansible.cfg (in the home directory)
    - /etc/ansible/ansible.cfg (master configuration)
  - Configuration can also be set in environment variables
  - Some commonly used settings:
    - ansible_managed
    - forks
    - Inventory

### A Brief Tour of the Ansible Configuration File
The Ansible master configuration file is reviewed on a live system in this demonstration. Key configuration values are discussed as well as how to modify those values.
  
- Let's see some default values of *ansible.cfg* file located by `/etc/ansible/ansible.cfg` directory
```
[defaults]

# some basic default values...

#inventory      = /etc/ansible/hosts
#library        = /usr/share/my_modules/
#module_utils   = /usr/share/my_module_utils/
#remote_tmp     = ~/.ansible/tmp
#local_tmp      = ~/.ansible/tmp
#plugin_filters_cfg = /etc/ansible/plugin_filters.yml
#forks          = 5
#poll_interval  = 15
#sudo_user      = root
#ask_sudo_pass = True
#ask_pass      = True
#transport      = smart
#remote_port    = 22
#module_lang    = C
#module_set_locale = False
```
  
- Another handy block is following
```
[privilege_escalation]
#become=True
#become_method=sudo
#become_user=root
#become_ask_pass=False
```

### LAB Getting Started with Ansible
##### Install Ansible on the control node.
- To install Ansible on the control node, run  ansible.
```
yum install ansible
```

- If package not found run
```
yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
```

##### Configure the `ansible` user on the control node for ssh shared key access to managed nodes. Do not use a passphrase for the key pair.
- To create a keypair for the ansible user on the control host, run the following:
  - `sudo su - ansible`
  - `ssh-keygen` (accept all defaults: press enter for each prompt)

- Copy the `public key` to both `node1` and `node2`.

- As the ansible user on the control host:
  - `ssh-copy-id node1` (accept the host key if prompted, authenticate as ansible user)
  - `ssh-copy-id node2` (accept the host key if prompted, authenticate as ansible user)

##### Create a simple Ansible inventory on the control node in `/home/ansible/inventory` containing `node1` and `node2`.
- On the control host:
  - `sudo su - ansible` (if not already ansible user)
  - `touch /home/ansible/inventory`
  - `echo "node1" >> /home/ansible/inventory`
  - `echo "node2" >> /home/ansible/inventory`

##### Configure sudo access for Ansible on `node1` and `node2` such that Ansible may use sudo for any command with no password prompt.
- Log in to node1 as cloud_user and edit the sudoers file to contain appropriate access for the ansible user:
  - `ssh cloud_user@node1`
  - `sudo visudo`
  - Add the following line to the file and save:
```
ansible    ALL=(ALL)       NOPASSWD: ALL
```

- Repeate these steps for `node2`.

##### Verify each managed node is able to be accessed by Ansible from the control node using the `ping` module. Redirect the output of a successful command to `/home/ansible/output`.
- To verify each node, run the following as the `ansible` user from the control host:
  - `ansible -i /home/ansible/inventory node1 -m ping`
  - `ansible -i /home/ansible/inventory node2 -m ping`
- To redirect output of a successful command to `/home/ansible/output`:
  - `ansible -i /home/ansible/inventory node1 -m ping > /home/ansible/output`


## Run Ad-Hoc Ansible Commands
### Run Ad-Hoc Ansible Commands
Learn how to use ad-hoc ansible commands for simple system managment. This lecture covers one of the key objectives for Red Hat exam 407.

- Overview:
    - What is an ad-hoc command in Ansible? 
    - Use cases for ad-hoc commands
    - Ad-hoc vs Playbook
    - Ansible command syntax
    - Common modules

- What is an ad-hoc command in Ansible
    - You can run ansible either ad-hoc or as a playbook
    - Both methods have the same capabilities
    - Ad-hoc commands are effectively one-liners

- Use cases for Ad-hoc
    - Operational commands
        - Checking log contents
        - Daemon control
        - Process management
    - Informational commands
        - Check installed software
        - Check system properties
        - Gather system performance information
    - Research
        - Work with unfamiliar modules on test systems
        - Practice for playbook engineering

##### Ad-hoc vs Playbook
  
![img](https://github.com/Bes0n/EX407-Ansible-Automation/blob/master/images/img2.png)
  
##### Common Modules

![img](https://github.com/Bes0n/EX407-Ansible-Automation/blob/master/images/img3.png)

![img](https://github.com/Bes0n/EX407-Ansible-Automation/blob/master/images/img4.png)

![img](https://github.com/Bes0n/EX407-Ansible-Automation/blob/master/images/img5.png)


### Demonstration: Ansible Ad-Hoc Commands Part 1
documenation for specific modules can be collected using the ansible-doc command described in https://linuxacademy.com/cp/courses/lesson/course/2035/lesson/1/module/198
  
- Let's use `yum` as an example of ad-hoc command
    - `ansible myserver.example.com -i inv.ini -m yum -b -a "name=elinks state=latest"` - install **elinks** with **latest** version
        - `-i` - key for inventory host file
        - `-m yum` - use `yum` module 
        - `-b` - become (by default become **root**)
        - `-a "name=elinks state=latest"` - arguments. For `yum` module we're using **name** and **state**
    - `ansible myserver.example.com -i inv.ini -m yum -b -a "name=elinks state=absent"` - state **absent** will uninstall **elinks**