/eng99_IaC_ansible

Infrastructure as Code

  • Allows us to codify everything to automate processes with config management

IAC with Ansible

  • Heavily used within industry
  • IaC tool for configuration
  • Ansible uses YAML to write playbooks (aka scripts)

Why should we use Ansible?

  • Simple
  • Agentless
  • Fast
  • Dependencies include: Python
  • Compatibility with Linux-like and Microsoft

Configuration Management

  • ssh into controller
  • run update and upgrade commands to ensure it has internet
  • repeat for web and db

vagrant ssh controller vagrant ssh web vagrant ssh db

sudo apt-get update -y
sudo apt-get upgrade -y
sudo apt-get install software-properties-common -y
sudo apt-add-repository ppa:ansible/ansible -y
sudo apt-get install ansible -y

Connecting Vagrant controller with other instances

  • Access to the hosts file

  • May be worth deleting and writing new file rather than editing cd /etc/ansible sudo nano hosts

  • Details to put into hosts file in controller

[web]
192.168.33.10 ansible_connection=ssh ansible_ssh_user=vagrant ansible_ssh_pass=vagrant
[db]
192.168.33.11 ansible_connection=ssh ansible_ssh_user=vagrant ansible_ssh_pass=vagrant
  • Accessing other instances manually ssh vagrant@***IP_ADDRESS***
  • Enavling the controller to automatically enter agent nodes
ssh-keyscan -H 192.168.33.10 >> ~/.ssh/known_hosts
ssh-keyscan -H 192.168.33.11 >> ~/.ssh/known_hosts
  • Pinging web app, database then everything in hosts
ansible web -m ping
ansible db -m ping
ansible all -m ping
  • Executing command in all instances ansible all -a "SOME COMMAND"
  • e.g.
ansible all -a "sudo apt-get update -y"
ansible all -a "sudo apt-get upgrade -y"
ansible all -a "ls"

ansible all -a "ls"

Types of Config Management

Push and Pull config Management?

Tools Available as IaC

Let's create Vagrantfile to create Three VMs for Ansible architecture

Ansible controller and Ansible agents

  • Vagrantfile Contents

# -*- mode: ruby -*-
 # vi: set ft=ruby :

 # All Vagrant configuration is done below. The "2" in Vagrant.configure
 # configures the configuration version (we support older styles for
 # backwards compatibility). Please don't change it unless you know what

 # MULTI SERVER/VMs environment
 #
 Vagrant.configure("2") do |config|
 # creating are Ansible controller
   config.vm.define "controller" do |controller|

    controller.vm.box = "bento/ubuntu-18.04"

    controller.vm.hostname = 'controller'

    controller.vm.network :private_network, ip: "192.168.33.12"

    # config.hostsupdater.aliases = ["development.controller"]

   end
 # creating first VM called web  
   config.vm.define "web" do |web|

     web.vm.box = "bento/ubuntu-18.04"
    # downloading ubuntu 18.04 image

     web.vm.hostname = 'web'
     # assigning host name to the VM

     web.vm.network :private_network, ip: "192.168.33.10"
     #   assigning private IP

     #config.hostsupdater.aliases = ["development.web"]
     # creating a link called development.web so we can access web page with this link instread of an IP   

   end

 # creating second VM called db
   config.vm.define "db" do |db|

     db.vm.box = "bento/ubuntu-18.04"

     db.vm.hostname = 'db'

     db.vm.network :private_network, ip: "192.168.33.11"

     #config.hostsupdater.aliases = ["development.db"]     
   end


 end