Kubernetes

Project Overview

This project sets up a lightweight Kubernetes cluster using Vagrant and VirtualBox. It provisions:

• One master node (k8s-master) that manages the cluster
• Two worker nodes (k8s-worker-1, k8s-worker-2) that run containerized workloads
• An embedded ETCD cluster running on the master node for storing Kubernetes cluster data

All virtual machines have the necessary dependencies installed, including:

• Docker container runtime
• Kubernetes components (kubeadm, kubectl, kubelet)
• Network configurations and optimizations
• ETCD, which is configured using the following configuration file:

  /etc/kubernetes/pki/etcd/ca.crt
  /etc/kubernetes/pki/etcd/server.crt
  /etc/kubernetes/pki/etcd/server.key

The master node is initialized with kubeadm, and Flannel is deployed as the pod network. Worker nodes are automatically configured to join the cluster.

Getting Started

To set up this Kubernetes project locally, first, clone the repository:

git clone https://github.com/DanielDimitrov1/k8s-vm-environment-lab.git

Navigate to the project directory and start the virtual machines using Vagrant:

cd k8s-vm-environment-lab
vagrant up

Once the setup is complete, follow the steps below to configure the cluster.

Setup Instructions

Joining Worker Nodes to the Cluster

1. Access the Master Node
   Connect to the master node using SSH.

   vagrant ssh master

2. Generate the Join Command
   Create a token that worker nodes will use to join the cluster.

   sudo kubeadm token create --print-join-command

   Copy the output.

3. Join Worker Nodes
   Use the generated token to connect each worker node to the cluster.

   vagrant ssh worker-1
   sudo <paste_command_from_master_node>

4. Verify Kubelet Status on the Master Node
   Ensure the Kubelet service is running on the master node.

   sudo systemctl status kubelet

   If it's inactive, start it:

   sudo systemctl start kubelet

Configure kubectl on the Master Node

5. Check if the .kube Directory Exists
   Verify if the kubeconfig file is available for kubectl to work.

   ls $HOME/.kube/config

   If the directory is missing, create it:

   mkdir -p $HOME/.kube
   sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
   sudo chown $(id -u):$(id -g) $HOME/.kube/config

6. Verify Node Status
   Check if all nodes have successfully joined the cluster.

   kubectl get nodes

Label Worker Nodes

7. Assign Worker Roles to Nodes
   Label worker nodes to indicate their role in the cluster.

   kubectl label node k8s-worker-1 node-role.kubernetes.io/worker=worker
   kubectl label node k8s-worker-2 node-role.kubernetes.io/worker=worker

ETCD Health Check

8. Check the ETCD Cluster Status
   Verify that the ETCD cluster is healthy and operational.

   kubectl exec -it -n kube-system etcd-k8s-master -- \
   etcdctl --cacert /etc/kubernetes/pki/etcd/ca.crt \
           --cert /etc/kubernetes/pki/etcd/server.crt \
           --key /etc/kubernetes/pki/etcd/server.key endpoint health

9. List ETCD Cluster Members
   Display the list of all ETCD members in the cluster.

   kubectl exec -it -n kube-system etcd-k8s-master -- \
   etcdctl --cacert /etc/kubernetes/pki/etcd/ca.crt \
           --cert /etc/kubernetes/pki/etcd/server.crt \
           --key /etc/kubernetes/pki/etcd/server.key member list