Infrastructure as Code IaC

IaC is used to speed up the process of configuration management or orchestration

Ansible

Infrastructure automation tool for configuration management
Connects via ssh

Advantages of Ansible

Ansible doesn’t use agents, and its code is written in YAML in the form of Ansible Playbooks, so configurations are very easy to understand and deploy.

simple
Agentless
IT automation

Practical example

create 3 instances
One Ansible controller instance - that will dictate the configuration of the two other instances in our network The controller virtual machine is the vm that has Ansible installed on it and the other instances do not require Ansible to be downloaded on them (Agentless)

Ubuntu 16.04 vm - webApp Ubuntu 16.04 vm - db

creating controller

we want to install ansible on the aws virtual machine we have created using the vagrantfile look at the system of ansible how to create host entries tell the controller which ips to communicate with

installing ansible on controller

ssh into aws virtual machine
sudo apt-get install software-properties-common -y
sudo apt-get update sudo apt-get install software-properties-common sudo apt-add-repository ppa:ansible/ansible sudo apt-get update sudo apt-get install ansible sudo apt-get install tree

cd etc/ansible - default location for files

ansible "name of vm" -m ping - code to communicate to other vms

192.168.33.10 - web 192/168.33.11 - db

[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 [aws] 192.168.33.12 ansible_connection=ssh ansible_ssh_user=vagrant ansible_ssh_pass=vagrant

this how we connect the controller to the vms

to ssh into the vms ssh vagrant@192.168.33.10

ping machines with ansible command

Instructions

First run the following up to run all the machines

vagrant up

Enter each VM update the packages:

vagrant ssh db sudo apt-get update exit

repeat steps but with app and aws

vagrant ssh app vagrant ssh aws

Enter the AWS and run this

sudo apt-get install software-properties-common -y sudo apt-add-repository ppa:ansible/ansible sudo apt-get install ansible -y # install ansible sudo apt-get install tree

Enter /etc/ansible folder

cd /etc/ansible tree

ansible.cfg, hosts and roles should appear

test no connected to app and

ping 192.168.33.11 ping 192.168.33.10 # testing connection with Db and app

Create Host entries

cd ../../etc/ansible sudo nano hosts

copy the following inside hosts

[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

vagrant ssh into the other vm

ssh vagrant@192.168.33.10 ssh vagrant@192.168.33.11

you will be asked to add a new ECDSA fingerprint. Password is vagrant

After adding these new fingerprints, sudo apt-get update

sudo apt-get update

ping the connections back in aws controller

ansible all -m ping

Ansible Ad Hoc Commands

ad hoc commads are one line commands that provide the functionality of ansible An Ansible ad-hoc command uses the /usr/bin/ansible command-line tool to automate a single task on one or more managed nodes. Ad-hoc commands are quick and easy, but they are not reusable

ad hoc commands - easy to use and gives a lot of information about a particular virtual machine. we can gather this information by gathering from the controller as oppose to the ssh'ing in to the vm itself

example of ad hoc commands

ansible web -a "date"

ansible db -a "uname -a"

ansible all -m shell -a "ls -a"

ansible all -a "free"

ansible atlanta -m copy -a "src=/etc/hosts dest=/tmp/hosts"

ansible all -m shell -a 'echo hello world'

ansible webservers -m file -a "dest=/srv/foo/a.txt mode=600"

ansible all -m shell -a "hostname -I" - returns ip address of vm
ansible all -m shell -a "ifconfig" - returns all ip addresses of vm

ansible all -m shell -a "uptime" - uptime of instances

ansible all -m shell -a "env" - environment variables of instances

ansible all -m shell -a "free" - returns free space of instances

Ansible playbooks

Playbooks are Ansible’s configuration, deployment, and orchestration language. written in YAML file ext is .yml or .yaml (yet another markup language)

YAML file start with three dashes (---) Kubernetes uses YAML Docker compose uses YAML widely used within the realm of infrastructure as code

we create the playbook within the Controller instances (the vm with ansible installed)

difference between ad hoc and playbook

the playbook operates just like a bash script but has more powerful functionality automates the tasks we need to carry out in multiple locations

command to run playbook: n

Spartabariallali/ansible_basics-