Setting up multi-node k3s cluster in any cloud provider of your choice

MultiNodeK3S.md

Multi node k3s cluster in spot instances

First create the number of spot instances you want

Lets assume we are creating 1 master node and 2 agent nodes

SSH into one instance which should be master and do the following

Name the host with explict name to avoid name colision

sudo -i

hostnamectl set-hostname master1

echo master1 > /etc/hostname

Now install K3S cluster

curl -sfL https://get.k3s.io | K3S_KUBECONFIG_MODE="644" INSTALL_K3S_EXEC="--tls-san x.x.x.x" sh -s -

enter public ip address of the EC2 instance on --tls-san

Make your cluster full Control Plane node

cat <<EOF > /etc/rancher/k3s/config.yaml
> cluster-init: true
> EOF

This may not work even with sudo so have to do that command in interractive sudo shell sudo -i

After doing that restart your k3s cluster

sudo systemctl restart k3s

• it should look like this when you do kubectl get nodes

NAME      STATUS   ROLES                       AGE   VERSION
master1   Ready    control-plane,etcd,master   13m   v1.27.7+k3s2

Take note of the node-token of the master node

sudo cat /var/lib/rancher/k3s/server/node-token

SSH into other two instances and do the following

Name the host with explict name to avoid name colision

sudo -i

hostnamectl set-hostname agent1

echo agent1 > /etc/hostname

here change the hostname in increment or any way you see fit

Install K3S agent in worker instances

curl -sfL https://get.k3s.io | K3S_URL=https://<master-node-public-ip>:6443 K3S_TOKEN=<master-node-token> sh -

• After installing agent in both instances go to master node and do kubectl get nodes, it should look like this

NAME      STATUS   ROLES                       AGE   VERSION
agent1    Ready    <none>                      92s   v1.27.7+k3s2
agent2    Ready    <none>                      10s   v1.27.7+k3s2
master1   Ready    control-plane,etcd,master   23m   v1.27.7+k3s2

Now your multi node K3S cluster is ready