k3s cluster on multipass instances

This script will create a configurable amount of instances using multipass, install k3s server(s) (HA using embedded etcd), and add the agent instances to the cluster.

Requirements

• multipass (See multipass: Install Multipass)

Running it

Clone this repo, and run the script:

bash multipass-k3s.sh

This will (defaults):

• Generate random name for your cluster (configurable using NAME)
• Create init-cloud-init file for server to install the first k3s server with embedded etcd (contains --cluster-init to activate embedded etcd)
• Create one instance for the first server with 2 CPU (SERVERCPUMACHINE), 10G disk (SERVERDISKMACHINE) and 1G of memory (SERVERMEMORYMACHINE) using Ubuntu focal (IMAGE)
• Create cloud-init file for server to install additional k3s servers with embedded etcd.
• Create one instance for additional server (configurable using SERVERCOUNTMACHINE)
• Create cloud-init file for agent to join the cluster.
• Create one machine (configurable using AGENTCOUNTMACHINE) with 1 CPU (AGENTCPUMACHINE), 3G disk (AGENTDISKMACHINE) and 512M of memory (AGENTMEMORYMACHINE) using Ubuntu focal (IMAGE)
• Wait for the nodes to be joined to the cluster
• Optionally merge the generated kubeconfig with the existing $KUBECONFIG (MERGE_KUBECONFIG)

Quickstart Ubuntu 22.04 droplet

sudo snap install multipass
wget https://raw.githubusercontent.com/superseb/multipass-k3s/master/multipass-k3s.sh
bash multipass-k3s.sh
curl -Lo /usr/local/bin/kubectl "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
chmod +x /usr/local/bin/kubectl
kubectl --kubeconfig *-kubeconfig.yaml get nodes

Clean up

The files that are created are:

• $NAME-agent-cloud-init.yaml
• $NAME-cloud-init.yaml
• $NAME-kubeconfig.yaml
• $NAME-kubeconfig-orig.yaml
• $NAME-kubeconfig-backup.yaml (if MERGE_KUBECONFIG is set)
• $NAME-kubeconfig-merged.yaml (if MERGE_KUBECONFIG is set)