Context

Last week I resumed my journey into Kubernetes by setting up a K3s cluster in my Home Lab. Previously, I managed services using Docker Compose and Portainer, which was fun but required more manual effort to add new nodes.

Having acquired a Dell OptiPlex 3070 and installed Proxmox, I decided to test various approaches to streamline my setup.

Requirements

1. At least 3 nodes: one master node and two agent nodes
2. Host machine able to connect to all nodes
3. Ansible and Git installed on your host machine

Guide

Step 1: Clone the Repository

Clone the k3s-ansible repository from GitHub:

git clone [email protected]:k3s-io/k3s-ansible.git

Step 2: Navigate to Directory

Enter the newly created directory:

cd k3s-ansible

Step 3: Duplicate Inventory File

Create your own inventory file by duplicating the sample:

cp inventory-sample.yml inventory.yml

Step 4: Configure Inventory

Add your server and agent hosts in the inventory file:

---
k3s_cluster:
  children:
    server:
      hosts:
        192.16.35.11:
    agent:
      hosts:
        192.16.35.12:
        192.16.35.13:

Tips:

• To overwrite the default SSH user, add to vars:

  vars:
    ansible_user: worker
  

• To use password-based SSH login:

  vars:
    ansible_password: PASSWORD
    ansible_become_password: PASSWORD
  

  However, using public key for authentication is highly recommended.

Step 5: Set K3s Token

Generate and set a secure token:

vars:
  token: aaaaaa

Tip: Generate a random secure token using:

openssl rand -base64 64

Step 6: Run Ansible Playbook

Execute the playbook to set up the K3s cluster:

ansible-playbook playbooks/site.yml -i inventory.yml

Expected output:

PLAY RECAP *********************************************************************
192.16.35.11             : ok=25   changed=0    unreachable=0    failed=0    skipped=62   rescued=0    ignored=0   
192.16.35.12             : ok=20   changed=0    unreachable=0    failed=0    skipped=40   rescued=0    ignored=0   
192.16.35.13             : ok=20   changed=0    unreachable=0    failed=0    skipped=40   rescued=0    ignored=0   

Result

To verify the setup, log in to the master node and run:

kubectl get nodes

Output should list all three nodes (one master, two agents):

NAME                 STATUS   ROLES                  AGE   VERSION
k3s-master           Ready    control-plane,master   1m    v1.22.5+k3s1
k3s-agent-1          Ready    <none>                 1m    v1.22.5+k3s1
k3s-agent-2          Ready    <none>                 1m    v1.22.5+k3s1

Conclusion

You have successfully set up a K3s cluster using Ansible! With your K3s cluster running, you can now explore deploying applications and setting up a CI/CD pipeline.

Happy Kubernetes-ing!