Setting up Ansible on AWS EC2 Instance

Thomas Suebwicha

6 min readOct 23, 2020

By Thomas Suebwicha

Written June 17, 2020

Last Edited October 23, 2020

Requirements

2 free tier AWS EC2 Instances running

A — Free Tier Amazon Linux (This will act as the master)
B — Free Tier Ubuntu 18.04 (Server that we will do stuff to)
C — Free Tier Ubuntu 18.04 (Server that we will do stuff to)

NOTE: The execution commands can vary depending on your machine type

Outline

Setting up AWS EC2 Instances
Setting up Ansible
Setting up Ansible Project
Execution

1. Setting up AWS EC2 Instances

Create the following instances in your AWS Instances list:

NOTE: There are no configuration changes when making them and so can click on the “Review and Launch Button”.

A — Free Tier Amazon Linux (This will act as the master)

B — Free Tier Ubuntu 18.04 (Server that we will do stuff to)

C — Free Tier Ubuntu 18.04 (Server that we will do stuff to)

To make this process easier, Create a PEM key that is the same for each of the three. I.E. One pem key can be used to access all three for this demonstration.

Example

As you can see awssydneya is private key that will be used for all three instances.

You may access each instance by your ssh agent in command line or shell. Here is the following structure.

$ ssh -i <path to pem>/awssydneya.pem user@<public DNS address>

For me it was as follows

Amazon Linux (Current directory contains pem key & user is ec2-user)
Ubuntu (Current directory contains pem key & user is ubuntu)

NOTE: Every time you start and stop your instance, the public DNS address changes!

On all instances please update and install accordingly such that it is up to date.

Amazon Linux
Ubuntu

2. Setting up Ansible

On Instance A we will install ansible

#Perform a quick update on your instance
$ sudo yum update -y
 
#Install ansible in your EC2 instance
$ sudo pip install ansible

Verify that ansible is install correctly

$ ansible --version

(Optional) Setting up Git

We could use Git as version control for this ansible project.

Amazon Linux
Ubuntu

Verify it is installed correctly with a response of specific version.

$ git --version

3. Setting up Ansible Project

Please find a copy of the project files here on github.

Make a new directory in the home & direct current directory into there

mkdir playbook
cd ./playbook

Required file structure for this project below

playbooks
  ansible.cfg
  hosts
  keypair.pem
  web-notls.yml
  files
    nginx.conf
  templates
    index.html.j2

We will go through each file and what they consist of.

ansible.cfg File

This is the configuration file. Instead of housing this information for each individual host, we are able to abstract it in here.

[defaults]
inventory = hosts
remote_user = ubuntu
private_key_file = /home/ec2-user/playbooks/keyfile.pem

[defaults] is given to the last resort if no special configuration is labelled.

inventory specifies the hosts we intend to make the changes to.

remote_user is the username to access that instance/server.

private_key_file is path directory to the private key.

hosts File

This file will consist of the hosts we want to act upon. This will be Instance B & C. To inform ansible which servers to act upon we will do the following.

$ vim hosts

Displays

[webservers]
testserver ansible_host=ec2-3-25-79-101.ap-southeast-2.compute.amazonaws.com
testserverB ansible_host=ec2-13-210-104-229.ap-southeast-2.compute.amazonaws.com

[webservers] is the group label below.

“testserver” is the name of instance B with its domain name server given to ansible_host.

To Test connection with all the hosts, we are able to ping them all by selecting their group label.

ansible webservers -m ping

You should see green writing with “SUCCESS” otherwise red writing with an error.

The ECDSA key fingerprint is just confirming you want to connect with a new server.

Web-notls.yml File

This is what our web-notls.yml will look like.

---
- name: Configure webserver with nginx
  hosts: webservers
  become: True
  tasks:
    - name: install nginx
      apt: name=nginx update_cache=yes- name: copy nginx config file
      copy: src=files/nginx.conf dest=/etc/nginx/sites-available/default- name: enable configuration
      file: >
        dest=/etc/nginx/sites-enabled/default
        src=/etc/nginx/sites-available/default
        state=link- name: copy index.html
      template: src=templates/index.html.j2 dest=/usr/share/nginx/html/index.html
        mode=0644- name: restart nginx
      service: name=nginx state=restarted

Keypair.pem File

Create a pem key named “keypair” that will have the same content as our awssydneya.pem on the host computer.

vim keypair.pem

Inside, make sure you are in “INSERT” mode. Go to “awssydneya.pem” and open in text editor then copy and paste the content into vim with a right click. You should see it auto typing.

chmod 700 keypair.pem

Since this we will be deploying nginx basic server page we will want to expose ports 8080(through the inbound rules of AWS).

Click on security group

Edit Inbound rules as follows

NOTE: Won’t be setting up TLS encryption since this would make it more complex

nginx.conf File

We need to create a directory called “files”. This follows the ansible folder layout.

In there we will put the following information.

server {
        listen 8080 default_server;
        listen [::]:8080 default_server ipv6only=on;root /usr/share/nginx/html;
        index index.html index.htm;server_name server_name ec2-3-25-79-101.ap-southeast-2.compute.amazonaws.com ec2-13-210-104-229.ap-southeast-2.compute.amazonaws.com;location / {
                try_files $uri $uri/ =404;
        }
}

Change the server_name to be public DNS of Instance B & C.

index.html.j2 File

Create a directory called templates. In there a file called index.html.j2.

Copy this default template.

<html>
  <head>
    <title>Welcome to ansible</title>
  </head>
  <body>
  <h1>nginx, configured by Ansible</h1>
  <p>If you can see this, Ansible successfully installed nginx.</p><p>Running on {{ inventory_hostname }}</p>
  </body>
</html>

Inventory_hostname specifies the name given to that host.