Resources Created

• VPC with 3 private and public subnets.
• 1 NAT Gateway.
• Security Groups for the load balancer and Kubernetes (K8s) nodes.
• Key pair for the nodes.
• Network Load Balancer (NLB) and target group for the master nodes.
• Ansible hosts for master and worker nodes.

SSH Access to Private Instances via Public Jumpbox (Bastion)

To SSH into a private instance through a public jumpbox (bastion):

ssh -i private-key.pem -o ProxyCommand="ssh -i private-key.pem -W %h:%p ubuntu@<bastion_public_ip>" ubuntu@<private_ip>

Steps to Add a New Master Node

1. Add a new EC2 instance for the master node.
2. Update the null_resource.update_hosts to include the new master.
3. Add the new master to the aws_lb_target_group_attachment.
4. Include the new master node in ansible.tf under the Ansible hosts.
5. Add an output for the private IP of the new master.

Once the above changes are made, run:

terraform apply

This will automatically add the new master node to the cluster.

Removing a Master Node

Before removing a master node resource, you must drain and delete the node from the Kubernetes cluster. Execute the following commands:

kubectl drain master3 --ignore-daemonsets
kubectl delete node master3