Install Ansible on Ubuntu and configure a control node and a target node

Ansible is an open-source automation tool used for IT tasks such as configuration management, application deployment, and task automation. Here are some key features and concepts of Ansible:

Key Features:

1. Agentless: Ansible does not require any agent software to be installed on the nodes it manages. It uses SSH for communication.
2. Easy to Learn: Ansible uses a simple syntax written in YAML called playbooks.
3. Idempotency: Ansible ensures that changes are applied only when necessary, making it safe to run multiple times without causing unintended effects.
4. Extensible: Ansible modules can be written in any language that can return JSON.
5. Scalable: Ansible can manage small environments to large-scale deployments.

Before Installing Ansible, I must ensure that Python is already installed on control node and a target node

Step 1: Install Ansible on the Control Node

1 .Update the package list:

sudo apt update

2 .Install Ansible:

sudo apt install ansible -y

3 .Verify the installation:

ansible --version

Output

Step 2: Configure SSH Access from Control Node to Target Node

1. Generate SSH keys on the control node (if not already done):

ssh-keygen

Output

• RSA is the default algorithm that will be used
• Keys are generated by using SHA26
• id_rsa : Private Key
• id_rsa.pub : Public key
• Passphrase(not mandatory): a secret that the user must type to use the private key.

2 .Locate the SSH public key on the control node:

The SSH public key is usually located in the ~/.ssh directory and typically named id_rsa.pub or id_ecdsa.pub. You can list the files in this directory to find the correct one:

ls ~/.ssh

3. Display the contents of the SSH public key:

Use the cat command to display the contents of your public key file:

cat ~/.ssh/id_rsa.pub

Copy the entire output.

4. Connect to the target node:

Use SSH to connect to the target node:

ssh user@target_node_ip

Replace user with the username and target_node_ip with the IP address of the target node.

5. Create the .ssh directory on the target node (if it doesn't exist):

mkdir -p ~/.ssh chmod 700 ~/.ssh

Append the public key to the authorized_keys file:

On the target node, open the authorized_keys file in an editor:

nano ~/.ssh/authorized_keys

Paste the public key content you copied earlier into this file. Save and close the file

Set the correct permissions for the authorized_keys file:

chmod 600 ~/.ssh/authorized_keys

6 . Verification

Log out of the target node:

exit

Test passwordless SSH from the control node to the target node:

ssh user@target_node_ip

You should be able to log in without being prompted for a password.

Step 3: Configure Ansible Inventory File

Edit the inventory file (default location is /etc/ansible/hosts):

sudo nano /etc/ansible/hosts

uncommit the file add the target node details.

Replace user with the username and target_node_ip with the IP address of the target node.

[webservers]
user@target_node_ip

save the file

Step 4: Test the Connection

Ping the target node using Ansible:

ansible webservers -m ping

You should see a response indicating success.

It’s done