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Ansible Cheatsheet

Ansible

Install ansible linter to check the file is ok or not:

sudo apt install ansible-lint

then:

ansible-lint playbook.yaml

Check if the server is running:

ansible all -i hostname, -m ping

Expected output:

hostname | SUCCESS => {
    "changed": false,
    "ping": "pong"
}

Run command on host:

ansible all -i hostname, -m shell -a 'echo hello world'

Playbook file should name something like FILENAME.yaml.

it's better to describe the name of the file base on the task of that file like apache.yaml.

{% code-tabs %} {% code-tabs-item title="apache.yaml" %}

---
- hosts: all
  remote_user: root
  tasks:
  - name: Install Apache2 on server
    yum:
      name: httpd
      state: present
  - name: Ensure that apache2 is running
    service:
      name: httpd
      state: started
      enable: True
    become: True

{% endcode-tabs-item %} {% endcode-tabs %}

Run the playbook:

ansible-playbook -i hostname, apache.yaml

Show all configs and variables of a host:

ansible all -i hostname, -m setup

Using Ansible setup variable:

{% code-tabs %} {% code-tabs-item title="ansible_var.yaml" %}

---
- hosts: all
  remote_user: root
  tasks:
  - name: debugging from setup 
    debug:
      msg: "OS version is '{{ ansible_distribution }}' '{{ ansible_distribution_file_variety }}' with IP: '{{ ansible_all_ipv4_addresses }}'"

{% endcode-tabs-item %} {% endcode-tabs %}

Output:

TASK [debugging from setup] ********************************************************************************************************************************************
ok: [centosvm] => {
    "msg": "OS version is 'CentOS' 'RedHat' with IP: '['192.168.43.111', '192.168.43.64']'"
}

Inline var:

{% code-tabs %} {% code-tabs-item title="var1.yaml" %}

---
- hosts: all
  remote_user: root
  tasks:
  - name: Variable assigning
    set_fact:
        pkg1: sqlite
  - name: Install Apache2 on server
    yum:
      name: httpd
      name: "{{ pkg1 }}"
      state: present
  - name: Ensure that apache2 is running
    service:
      name: httpd
      state: started
    become: True

{% endcode-tabs-item %} {% endcode-tabs %}

then run the playbook.

Another way:

{% code-tabs %} {% code-tabs-item title="var2.yaml" %}

---
- hosts: all
  remote_user: root
  tasks:
  - name: Install Apache2 on se
rver
    yum:
      name: httpd
      name: "{{ pkg1 }}"
      state: present
  - name: Ensure that apache2 is running
    service:
      name: httpd
      state: started
    become: True

{% endcode-tabs-item %} {% endcode-tabs %}

and execute this:

 ansible-playbook -i hostname, var.yaml -e 'pkg1=vim'

on CentOS, enable the EPEL

{% code-tabs %} {% code-tabs-item title="epel.yaml" %}

---
- hosts: all
  remote_user: root
  tasks:
  - name: Install epel
    yum:
      name: epel-release
      state: present

{% endcode-tabs-item %} {% endcode-tabs %}

upgrade a package

{% code-tabs %} {% code-tabs-item title="apache_upgrade.yaml" %}

---
- hosts: all
  remote_user: root
  tasks:
  - name: Install Apache2 on s
erver
    yum:
      name: httpd
      state: latest

{% endcode-tabs-item %} {% endcode-tabs %}

Or upgrade all:

{% code-tabs %} {% code-tabs-item title="upgrade.yaml" %}

---
- hosts: all
  remote_user: root
  tasks:
  - name: Upgrade all packages
    yum:
      name: "*"
      state: Latest

{% endcode-tabs-item %} {% endcode-tabs %}

to list all tasks:

ansible-playbook taskname.yaml --list-tasks

Generating static files using jinja2 and ansible

{% code-tabs %} {% code-tabs-item title="jinja.yaml" %}

---
- hosts: all
  remote_user: root
  tasks:
  - name: testing jinja2
    template:
      src: index.html.j2
      dest: /var/www/html/index.html
      owner: root
      group: root
      mode: 0644

{% endcode-tabs-item %} {% endcode-tabs %}

{% code-tabs %} {% code-tabs-item title="index.html.j2" %}

<html>
<body>
<h1>Hello World!</h1>
<p>This page was created on {{ ansible_date_time.date
}}.</p>
{% if ansible_eth0.active == True %}
<p>eth0 address {{ ansible_eth0.ipv4.address }}.</p>
{% endif %}
</body>
</html>

{% endcode-tabs-item %} {% endcode-tabs %}

More Doc for Jinja2

Working with Hosts

{% code-tabs %} {% code-tabs-item title="hostname.txt" %}

[general]
192.168.1.100
ex.sample.com
ex[1:2].sample.com
db.sample.com

[webserver]
192.168.1.100
ex2.sample.com

[database]
db.sample.com

{% endcode-tabs-item %} {% endcode-tabs %}

Sample of a playbook which only run tasks on webserver group

{% code-tabs %} {% code-tabs-item title="apache.yaml" %}

---
- hosts: webserver
  remote_user: root
  tasks:
  - name: Install Apache2 on server
    yum:
      name: httpd
      state: present
  - name: Ensure that apache2 is running
    service:
      name: httpd
      state: started
      enable: True
    become: True

{% endcode-tabs-item %} {% endcode-tabs %}

for running:

ansible-playbook -i hostname.txt, apache2.yaml

In this section, I decided to write more about variables. but i think i should refer you to the Official Documents.

please note that you should also read the documents of ansible for each modules's variable for better performance.

for working with iteration use with_items

{% code-tabs %} {% code-tabs-item title="general.yaml" %}

---
- hosts: all_machines
  remote_user: root
  tasks:
  - name: install nececery tools
    yum:
      name: '{{ item }}'
      state: present
    with_items:
    - vim
    - sqlite
    - openjdk-jre
    - docker

{% endcode-tabs-item %} {% endcode-tabs %}

other method. make a backup of a file/directory

{% code-tabs %} {% code-tabs-item title="general.yaml" %}

---
- hosts: all_machines
  remote_user: root
  vars:
    dirs:
    - /etc/named.conf
    - /var/www/html/index.html
    users:
    - numb
  tasks:
  - name: ensure user is exist
    users:
      name: '{{item}}'
    become: yes
    with_items:
    - '{{ users }}'
    - name: ensure user directories exist
     file:
       path: '/home/{{ item }}'
       state: directory
     become: yes
     with_items:
     - '{{ users }}'
     - name: copy / backup files from src to dest
     copy: 
       src: '{{ item.0 }}'
       dest: '/home/{{ item.1 }}'
     become: yes
     with_nested:
     - '{{ dirs }}'
     - '{{ users }}'

{% endcode-tabs-item %} {% endcode-tabs %}

working with sequences:

{% code-tabs %} {% code-tabs-item title="sequence.yaml" %}

---
- hosts: webservers
  remote_user: root
  tasks: 
  - name: create some file in sequence
    file:
      dest: '/home/backup{{ item }}'
      state: directory
    with_sequence: start=1 end=4
    become: yes

{% endcode-tabs-item %} {% endcode-tabs %}

you can also change hostname with sequences

condition could be look like this:

{% code-tabs %} {% code-tabs-item title="apache.yaml" %}

---
- hosts: webserver
  remote_user: root
  tasks:
  - name: Install Apache2 on Redhat based
    yum:
      name: httpd
      state: present
    when: ansible_os_family =='RedHat'
  - name: Install Apache2 on debian based
    apt:
      name: apache2
      state: present
    when: ansible_os_family == 'Debian'
  - name: Ensure that apache2 is running
    service:
      name: httpd
      state: started
      enable: True
    become: True

{% endcode-tabs-item %} {% endcode-tabs %}

Boolean condition

---
- hosts: all
  remote_user: ansible
  vars:
   backup: True
  tasks:
  - name: Copy the crontab in tmp if the backup variable is true
  copy:
    src: /etc/crontab
    dest: /tmp/crontab
    remote_src: True
  when: backup

simply create ansible project structure with this:

mkdir -p roles/common/{tasks,handlers,templates,files,vars,defaults,meta}
touch roles/common/{tasks,handlers,templates,files,vars,defaults,meta}/main.yml

secret vault

inventory example

[servers:vars]

ansible_user=numb
ansible_become=yes
ansible_become_method=sudo 
ansible_become_pass='{{ server_pass }}'

create a new encripted secret file

ansible-vault create passwords.yml

after adding password for file add this to the opened file

server_pass: PASSWORD

then run the ansible

ansible-playbook -i inventory --ask-vault-pass --extra-vars '@passwords.yml' ansible.yml

TODO

write about roles structure, templates, groups, helpers, bash module, docker module, python module, diff, optimizing.