Infrastructure as Code IAC

Why do we use it?

To help speed up the process of configuration management or orchestration

For config management we use Ansible
For orchestration we use terraform

How does it speed the process?

By creating a script in YML using Ansible

Many servers running all around the world in the cloud
- YMAL = we can create one file in the controller and define what items we want to install in one file, and then we would like to update both servers (VMs with the relevant things)

What is Ansible ?

Automation tool for configuration management

Why should we use Ansible?

its simple, agentless, IT automation tools
Agentless? = we do not need to install ansible in app, or db servers, we just need it in the controller and connectivity from controller to the servers
Allows us to connect to any server in the world using ssh

How so we connect?

connect using ssh = related to simplicity
3 VMs- 1 will be a virtual controller , app and db

What are the dependencies?

Python in both VM App and VM db (ubuntu 16.04 has python configured already)

How does it fit into DevOps/ Benefit DevOps?

Saves time, open source, makes config management predictable, cost effective
it automates the process of configuration management
open source = we dont need to buy it = provides detailed documentation online for ease of use
does not diffrentiate between different providers as long as you have the correct script written

Step 1: Created a Vagrantfile & README.md

Step 2: `vagrant up`

Step 3: ssh into all VMs and run `sudo apt-get update` to check the connectivity of internet for all 3

Step 4: Now we need to use one VM as the Controller

we will use AWS for this
therefore need to install Ansible on chosen controller
look at the file system on controller using tree
consider how to create hoest entries
tell controller which IPs to communicate with

Step 5: Go inside controller VM and run relevant installation commands

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

Step 6: install tree to view folders in an organised way

sudo apt-get install tree

Step 7: enter inside ansible folder

cd /etc/ansible and enter tree command

Step 8: Test if other VM IPs are reachable (Testing network connectivity)

ping 192.168.33.11
ping 192.168.33.10

should respond with pong if successful

Go into hosts file and edit to enter the IP details of the VMs that will be used from 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

we have told the hosts file that these are the 2 servers that we would like ansible controller to communicate with

Step 9: SSH into the VMs

ssh vagrant@IP

sudo apt-get update

exit

do this to ensure you can connect to the VMs and they have internet connectivity

Step 10: Ping these machines with ansible command

sudo ansible all -m ping

checks network connectivity

** ERROR = AWS VM WAS CORRUPT SO HAD TO USE WEB AS THE CONTROLLER AND AWS AS WEB ** ** HAD TO DELETE ANSIBLE FOLDER MANUALLY IN VAGRANT AND REINSTALL ON THE WEB VM IN ORDER TO USE AS CONTROLLER

echo /home/vagrant/.ansible/tmp/ansible-tmp-15

Step 11: Ansible ad-hoc commands

Why should we use them and not playbook?

its easy, fast, robust with one command we can find out space, what is already installed etc

ansible aws -a "date"
ansible db -a "uname -a"
ansible all -a "ls -a"
ansible all -m shell -a "ls -a"
ansible all -m shell -a "free"
ansible all -m shell -a 'uptime' --become
ansible all -m shell -a "env"
[displays all env variables]
ansible all -m shell -a "ip addr"
[displays all ip addresses]
ansible all -m shell -a 'ps -ef' 
ansible all -m shell -a 'ps -a'
ansible all -m shell -a "ifconfig"
ansible db -m shell -a "hostname -I"
[returns private and public ip nothing else]

Step 12: Ansible playbook

What are they?

YAML (Yes another markup language) .yml or .ymal
Units of scripts which describe work to configure server/servers

Syntax

--- starts with 3 dashes
indentation is super important in YAML

Widely used in DevOps Practices!!

Why should we use them/benefits?

for configuration management - install programs, update programs etc
why over ad hoc commands? it automates the tasks in multiple servers

Step 13: Creating a playbook

in ansible folder create a new file

sudo nano nginx install_nginx_on_web.yml

Edit the file

# this is YAML file to install nginx in our web server

---

# where do we want to install
- hosts: aws

# get the facts
  gather_facts: yes

# work from root user
  become: true

# what do we want ansible to do for us in this playbook?
  tasks:
  - name: Install nginx

# telling ansible which package to install and the state of it - states are: present/absent
    apt: pkg=nginx state=present

ansible-playbook install_nginx_on_web.yml
Run the IP given (web VM) on browser

ugneokmanaite/Ansible_Intro