Day 15 | Ansible Ad-Hoc Commands and Playbooks: A Deeper Dive

In the realm of IT automation, Ansible shines as a radiant star, illuminating the path to seamless and efficient management of the infrastructure. This journey begins with two enchanting spells: Ad-Hoc Commands & Ansible Playbook

Prerequisites:

Two Servers (In this case I have created two severs on AWS both Ubuntu, free tier
and named them as

• Ansible_server

• target_server (the host)

On the Ansible_server

Connect to the server using "ssh -i keypair.pem ubuntu@publicipaddress"

I was able to connect to the ansible_server.

Next step update using sudo apt update.

The next step would be Installing ansible by sudo apt install ansible.

Next to check if we have successfully installed Ansible go with " ansible --version."

Now establishing password-less communication with the target_server we can achieve this by doing ssh-keygen.
This act will create a bunch of files like authorized_keys, and private, and public keys in a certain location. (/home/unbuntu/.ssh)

Navigate to the location of this public key and open the id_rsa.pub key using cat id_rsa.pub

On the target_server

Take a new terminal and Connect to the server using "ssh -i keypair.pem ubuntu@publicipaddress". The same way we did on the other server.

Next step update using sudo apt update. The same way we did on the other server.

Then ssh-keygen which will create a bunch of files like authorized_keys, and private, and public keys in a certain location. (/home/unbuntu/.ssh). The same way we did on the other server.

Now Navigate to the (/home/unbuntu/.ssh) location and open the authorized_keys and place the public key id_rsa.pub of the ansible_server using

"vim /home/unbuntu/.ssh/authorized_keys". Then save the file.

Now let's check the connection, hop on to the ansible_server terminal and "ssh privateipaddress". (Why private ip address because both the instances are on the same VPC).

Now we have successfully been able to establish a password-less connection between both the ansible_server and target_server.

Now log out of the target_server.

The next thing is to create an "inventory file" using vim editor. In this inventory file, include the private IP of the target_server and save the file.

Now after creating an inventory file and adding the private ip address of the target_server, its time to create a file.

First Ansible Ad-Hoc Command:

With ansible -i inventory -m "shell" -a "touch ansiblefile1" command we can create a file called "ansiblefile1" on the target_server, where "-m" corresponds to the module and the -a flag corresponds to the "arguments" or "parameters" that you want to pass to the module specified by the -m flag.

1. Now hop on to the target_server terminal and check for the existence of "ansiblefile1" with ls -ltr. This command will reveal the creation of the file with the exact timestamp.

Hence, we have established a connection between ansible_server and target_server by a password-less authentication method and can create a file on ansible_server and deploy it on the target_server.

Installing Nginx and starting Nginx:

1. For this task let us create a playbook using vim first-playbook.yml.

Then include the following script. Ansible playbooks are written in "YAML" language, which is a widely used language by DevOps Engineers/AWS Engineers.

---
- name: Install Nginx
  hosts: all
  become: true

  tasks:
    - name: Install Nginx
      apt:
        name: nginx
        state: present

    - name: Start Nginx
      service:
        name: nginx
        state: started

Save the file and run the following command ansible-playbook -i inventory first-playbook.yml.

This shows that Nginx has successfully installed and it is up and running on the target_server.

To check, Now hop on to the target_server and check using sudo systemctl status nginx.

This should display the Nginx server installed on the targer_server and the status as up and running.