DevOps Classroom notes 02/Mar/2025

Key Based Authentication in Ansible

Key Based Authentication

• On linux servers we will have public key and private key with us
• to login ssh -i <path to private key> username@ipaddress
• Watch classroom video for key based setup on AWS
• IN Azure, we have ssh keys service where we can generate or import existing public keys

AWS Ansible Key based authentication

• Lets create an ec2 instance with some key pair
• We need to enable password based authentication
• Now create a user devops in the ec2 instance
• Give this user sudo permission with No Password
• Switch to the user ansible
• From the machine configure as control node, we create a key pair ssh-keygen and copy the public key generated into other nodes ssh-copy-id
• Once this configuration is done, install ansible and execute ansible ping

Enable password based authentication in AWS

• Change the PasswordAuthentication to yes in file /etc/ssh/sshd_config.d/60-cloudimg-settings.conf
• restart the sshd

sudo systemctl daemon-reload
sudo systemctl restart ssh

• Lets create a user called devops sudo adduser devops
• We need to give sudo permissions for devops without password prompting

sudo visudo

• Add the line devops ALL=(ALL:ALL) NOPASSWD:ALL
  
• Save the file
• now switch user and verify

Key based setup

• Login as devops user
• Now generate key pair ssh-keygen -t rsa -b 4096
  
• Now copy the public key to other nodes ssh-copy-id devops@<ip>
  

Ansible setup on AWS

• We have a user with sudo previleges on both the machines
• Now install ansible on control node

sudo apt update
sudo apt install software-properties-common
sudo add-apt-repository --yes --update ppa:ansible/ansible
sudo apt install ansible -y

• Since we have keys configured ansible -m ping -i hosts all