Build a Kubernetes cluster using k3s via Ansible

Author: https://github.com/itwars

K3s Ansible Playbook

Build a Kubernetes cluster using Ansible with k3s. The goal is easily install a Kubernetes cluster on machines running:

• Debian
• Ubuntu
• CentOS

on processor architecture:

• x64
• arm64
• armhf

System requirements

• Deployment environment must have Ansible 2.4.0+

• Master and nodes must have passwordless SSH access

• For an airgap installation (no outbound internet access on nodes), all asset files for your CPU architecture from https://github.com/k3s-io/k3s/releases/tag/{k3s_version} should reside on an HTTP share within your private environment, accessible by all target nodes. For some super quick ways to to share a folder via HTTP, check out this post. Any ordinary HTTP server will work as well.

  Example content for the HTTP folder when choosing the amd64 architecture and k3s version v1.27.2+k3s1 (notice the subfolder set to the version name):

  • v1.27.2+k3s1 (the subfolder containing the assets below)
  • v1.27.2+k3s1/k3s
  • v1.27.2+k3s1/k3s-airgap-images-amd64.tar
  • v1.27.2+k3s1/sha256sum-amd64.txt

  For arm64 respectively:

  • v1.27.2+k3s1 (the subfolder containing the assets below)
  • v1.27.2+k3s1/k3s-arm64
  • v1.27.2+k3s1/k3s-airgap-images-arm64.tar
  • v1.27.2+k3s1/sha256sum-arm64.txt

Usage

First create a new directory based on the sample directory within the inventory directory:

cp -R inventory/sample inventory/my-cluster

Second, edit inventory/my-cluster/hosts.ini to match the system information gathered above. For example:

[master]
192.16.35.12

[node]
192.16.35.[10:11]

[k3s_cluster:children]
master
node

If needed, you can also edit inventory/my-cluster/group_vars/all.yml to match your environment. For an airgap installation (see requirements above), please set airgapped to true and change remote_repo_url to point to your webserver root containing the k3s version subfolder, e.g. http://internalurlorip/k3s-binaries-and-images. Don't point this directly to the version subfolder itself (-> point it to the parent folder), and don't include a trailing /.

Start provisioning of the cluster using the following command:

ansible-playbook site.yml -i inventory/my-cluster/hosts.ini

Kubeconfig

To get access to your Kubernetes cluster just

scp debian@master_ip:~/.kube/config ~/.kube/config