Ansible Getting Started

This post includes some bits around Ansible Engine fundamentals.

Inventory

Intentory file location

$ /etc/ansible/hosts

Format

[cisco-ios-devices]
10.10.0.1
10.10.0.2

[cisco-nxos-devices]
10.10.20.1
10.10.20.2

Variables

[cisco-ios-devices]
10.10.0.1
10.10.0.2

[cisco-ios-devices:vars]
ansible_port=22
ansible_user=netadmin

Grouping

[cisco-ios-devices]
10.10.0.1
10.10.0.2

[cisco-nxos-devices]
10.10.20.1
10.10.20.2

[network-devices:children]
cisco-ios-devices
cisco-nxos-devices

Patterns

[cisco-nexus-7000]
nexus[01:04].companydomain.com

Generates the output below

nexus01.companydomain.com
nexus02.companydomain.com
nexus03.companydomain.com
nexus04.companydomain.com

Playbooks

Handlers

---
- hosts: webservers

  tasks: 
    - name: Install Nginx
      apt: pkg=nginx state=installed update_cache=true
      notify:
        - Start Nginx

  handlers:
    - name: Start Nginx
      service: name=nginx state=started

Roles

A role directory structure contains the directories below. Each directory must contain a main.yml

  • Defaults: default variables for the role
  • Vars: variables for the role
  • Tasks: the main list of steps to be executed by the role
  • Files: contains files which we want to be transferred to the host
  • Templates: file template which supports modifications from the role
  • Meta: contains metadata of role such as dependencies
  • Handlers: handlers which can be invoked by notify directives

Templates

- hosts: webservers
  vars:
    variable_to_be_replaced: 'value1'
    inline_variable: 'value2'
  tasks:
    - name: Ansible using templates
      template:
        src: template_example.j2
        dest: /userA/docs/personal_data.txt

Template file

template_example.j2


Variable given as inline -  -

Output

value1
Variable given as inline - value2 -

Loops

With_items

- name: Remove users from the system.
  user:
    name: ""
    state: absent
    remove: yes
  with_items:
    - userA
    - userB

With_nested

Define variables

users_with_items:
  - name: "userA"
    personal_directories:
      - "old_files"
      - "maps"
      - "usb_files"
  - name: "userB"
    personal_directories:
      - "old_files"
      - "backup"
      - "storage"

common_directories:
  - "docs"
  - "media"

 - name: Create common users directories using
  file:
    dest: "/home//"
    owner: ""
    group: ""
    state: directory
  with_nested:
    - ""
    - ""

Useful Commands

List group nodes

# ansible group-name --list-hosts

Modules

Files

Archive

- name: Backup Directory /var/log/application01/
  hosts: webservers
  tasks:
   - archive:
      path: /var/log/application01/
      dest: "/var/backups/application01-.tgz"

Copy

- name: Copy File
  hosts: webserver
  tasks:
   - copy:
      src: /var/log/application01/filename
      dest: "/var/backups/filename
      owner: root
      group: root
      mode: u=r,g=r,o=

Fetch

- name: Copy File from Remote Node
  hosts: webserver
  tasks:
   - fetch:
      src: /var/log/application01/filename
      dest: "/var/backups/

Delete a File

#Delete the file /backups/tmp/nodelist.txt on all servers
ansible all -b -m file -a "state=absent path=/backups/tmp/nodelist.txt"

Update a Line in File

#Update the line of text "MY_SETTING" to "BLUE" in /opt/configuration.txt on all servers
ansible all -b -m lineinfile -a "regexp=MY_SETTING line=BLUE path=/opt/configuration.txt"

Notifications

Slack

- name: Sending message to Slack Channel
    slack:
      token: ''
      channel: "#companynameAnsible"
      domain: "companyname.slack.com"
      parse: "full"
      color: "good"
      msg: 'The changes is completed on .'

Twilio

- name: Send an SMS to multiple phone numbers when the change is completed
    twilio:
      msg: The configuration change is completed!
      account_sid: XXXXXXXXXXX
      auth_token: XXXXXXXXXXX
      from_number: +34XXXXXXXXX
      to_number:
        - +34XXXXXXXX1
        - +34XXXXXXXX2
    delegate_to: localhost
Written on May 28, 2018