Kubernetes cluster setup using Kubeadm and Ansible

This repo contains two playbooks

1. Kubernetes nodes creation
2. Kubernetes cluster setup

Kubernetes nodes creation

You can skip to this section, If you already have nodes created to setup cluster.

System requirements:

• Apple mac
• CPU >= 8
• Memory >= 8GB

Note: If you are on windows or linux you could follow this guide to install multipass and create nodes.

Usage

By default this will create 3 nodes. You can update nodes count in roles/compute_resources/defaults/main.yml by adding/removing node_names

nodes:
  - controlplane
  - worker01
  - worker02
  - worker<n>

ansible-playbook kubernetes_nodes_creation.yaml

This will create 3 virtual machines with Ubuntu 22.04 LTS.

• 1 master node
• 2 worker nodes

It uses multipass tool to create virtual machines. It will also enable passwordless SSH access between nodes.

Note: Whenever you create virtual machines on mac , it will hold the ip address allocated to the machines and doesn't release automatically after virtual machines are deleted.You can release the ip address by removing the entries in /var/db/dhcpd_leases file in your mac.

List nodes

You could use below command to list the nodes created by multipass

multipass list

You should see output similar to below screenshot

SSH into nodes

You can connect to instance using multipass or direct SSH. You could use below command to enter inside node using multipass

multipass shell <node_name>

You could also use SSH command.You can get ip address from multipass list command.Private key file .ssh/kubernetes will be created as part of the above Ansible play.

ssh -i .ssh/kubernetes ubuntu@<ip_of_node>

Once you are inside any one of the machine, you can access other machines by just using

ssh <node_name>
# ssh controlplane
# ssh worker01

Kubernetes cluster setup

We need 1 node for master and atleast 1 node to act as worker. All nodes should have below requirements satisified. System requirements:

• Ubuntu or Debian OS
• Passwordless SSH connectivity between nodes

Usage

Update inventory.ini file with node ip details

[kube_master_nodes]
controlplane ansible_host=192.168.64.14

[kube_worker_nodes]
worker01 ansible_host=192.168.64.15
worker02 ansible_host=192.168.64.16

[kube_nodes:children]
kube_master_nodes
kube_worker_nodes

If you are using different user than ubuntu in your nodes then update group_vars/all.yml

service_account: <user_name>

If you havent added dns resolution for nodes to access using node names then update group_vars/all.yml to have ip of the node instead of nodename

master_node: <ip_of_the_master_node>

You can also update networking solution you wish to deploy.Currently it supports flannel, weave-net

network_solution: <solution_name>

Update SSH private_key_file path in your host machine in ansible.cfg. This will be used while access nodes from your machine.

You can now run the playbook using below command to setup the cluster on your nodes

ansible-playbook kubernetes_cluster_setup.yaml

If you want to run the workload from your host machine without entering inside controlplane then you can copy the kubeconfig to your local machine using below commands.

scp -i .ssh/<private_key_path> ubuntu@<controlplane_ip>:~/.kube/config .
# scp -i .ssh/kubernetes ubuntu@192.168.64.14:~/.kube/config .

Update controlplane ip in the config file

apiVersion: v1
clusters:
- cluster:
    ...
    server: https://<ip_of_controlplane>:6443

Now you can run the workloads from your host machine like below

kubectl --kubeconfig=config get all