DevOps Classroom Series – 12/Apr/2020

How to use custom roles

• Now Create a playbook to execute the roles
• Roles are generally referred from playbooks
  • Roles will be checked in
    1. relative to playbook filepath (./roles/<role-name>)
    2. in the home directory (~/.ansible/roles/<role-name>)
    3. in the ansible cfg directory (/etc/ansible/roles/<role-name>)
• Refer here for the playbook scripts

Dynamic Inventory

• Refer here for official docs
• Dynamic inventory is a script written in any language which returs a json file in a particular structure when –hosts is called or when –list
• Sample Structure of json

{
    'web': {
        'hosts': ['192.168.10.11', '192.168.10.12'],
        'vars': {
            'package_name': 'httpd',
            'ansible_ssh_user': 'ubuntu' 
        }
    },
    'db': {
        'hosts': ['192.168.11.11', '192.168.11.12'],
        'vars': {
            'username': 'admin',
            'password': 'admin@123'
        }
    }
}

• Example: Refer Here

Ansible Tower

• Is an orchestration tool around ansible which can be used using

  • Web Pages
  • REST API

• Ansible Tower is a paid tool

• For the labsetup, we would use a Ansible Tower trail version

• Ansible Tower Quick Start Guide Refer Here

• Using Ansible Tower is all about configuring ansible-playbook executions from ui/periodic scheduled jobs and from rest api .

• For Rest API refer here

• Ansible Tower will maintain logs of every run done by ansible.

Enterprise Scenario

• After writing Ansible Playbooks/Roles etc you need to run them from CI/CD Tools (like Jenkins/Azure DevOps) or from InfraProvisioning tools like Terraform/CloudFormation/ARM Templates

Exercise:

1. Refer Here

2. Write an Ansible Role to configure Tomcat 8 and then add playbooks to deploy gameoflife and openmrs into the Tomcat 8 Download Here

How to run the same ansible playbook for multiple environments

• Lets assume you have role called as tomcat8
• Lets assume you have a playbook called as useroledemo.yml
• Now lets assume we have 4 environments
  • dev
  • QA
  • Automated-QA
  • UAT
• Solution: For every environment create a separate inventory file
  • dev_hosts => ansible-playbook -i env\dev_hosts useroledemo.yaml
  • QA_hosts => ansible-playbook -i env\QA_hosts useroledemo.yaml
  • Automated-QA_hosts => ansible-playbook -i env\Automated-QA_hosts useroledemo.yaml
  • UAT_hosts=> ansible-playbook -i env\UAT_hosts useroledemo.yaml

Can i run Ansible Playbook on 100 nodes at same time

• Ansible-PLaybook has option called as forking (-f), if you want to run ansible on 100 servers at same time use “`ansible-playbook -f 100 useroledemo.yml’
• To run ansible-playbook on one server at a time

ansible-playbook -f 1 useroledemo.yml

What is synchronize module

• To recursively copy file then use synchronize module Refer Here