Kubernetes with K3S

K3s by Rancher is a lightweight kubernetes distribution, you can read more up on k3s.io

About our Setup

I will be using version 1.17.17 from the k3s releases page, if you remove the INSTALL_K3S_VERSION environment variable, the installation will default to the latest version.

To view more environment variables: - https://rancher.com/docs/k3s/latest/en/installation/install-options/

Deploy the Master

To deploy the master node:

curl -sfL https://get.k3s.io | K3S_KUBECONFIG_MODE="644" INSTALL_K3S_VERSION=v1.17.17+k3s1 sh -s -

Once the installation succeeds, the kubeconfig file is located at /etc/rancher/k3s/k3s.yaml but should already be in your environment and you should be able to list your nodes:

kubectl get nodes --output wide

Join a Agent to the Cluster

To add a worker node, we need to fetch the node-token from the master node:

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

Then proceed the installation by passing the master node's ip address as well as the node-token, we will assume that you stored the master ip address as MASTER_IP=x.x.x.x and the node-token stored as MASTER_NODE_TOKEN=xxxxx:

curl -sfL https://get.k3s.io | K3S_KUBECONFIG_MODE="644" INSTALL_K3S_VERSION=v1.17.17+k3s1 K3S_URL=https://${MASTER_IP}:6443 K3S_TOKEN=${MASTER_NODE_TOKEN}

Once the node joined the master you should be able to list the nodes from the master:

kubectl get nodes --output wide

Access Kubernetes from Outside

The kubeconfig on the master node has the localhost address in the config, so to access kubernetes from outside the node, we need to replace the master node's public or network reachable address:

sed "s/127.0.0.1/${}/g" /etc/rancher/k3s/k3s.yaml

Then store that output into a file ~/.kube/config.