Why?

We want to run a stable Kubernetes (k8s) cluster on multiple small Single Board Computers (SBC).

Current state

The scripts in this repo allow automated bootstrapping of a single master k8s. We use kubeadm to manage the cluster. The setup roughly follows the independent k8s setup instructions.

What's next?

• Adding additional storage
• High availability with more than one master and etcd

Setup

Hardware

This is implemented on a few Rock64 boards from Pine64. This mini computer is especially interesting because of its moderate price for relatively good compute power. It features 4 GiB of RAM and a quad core CPU as well as fast IO in form of eMMC storage, 1 Gbit ethernet and USB 3.0.

Operating system

Currently the OS is the well known rock64 Debian image provided by ayufan. Thanks a lot!

1. Get the latest stretch-minimal-rock64-* image from ayufan's rock64 releases and unpack it (e.g. with xz --uncompress).

2. Write the image to the eMMC or sdcard using dd or Etcher for more convenience.

3. Boot the new image with attached network cable. We depend upon internet access configured via DHCP. From now on we will adress the machine (host) by its local IP address.

Initial setup

Now we can install and configure our k8s stack. Here we assume that you save the rock64's IP address in the shell variable $host.

1. cmd/enable-ssh.sh $host

   This will establish key based authentication for SSH. Login with password will no longer work from remote. Your private key is stored in cluster/id_rsa. Don't lose it.

2. cmd/prepare-node.sh $host

   Ensures a unique hostname for each node.

3. cmd/install-dependencies.sh $host

   Installs needed software for a k8s node (e.g. docker, kubeadm and kubectl).

4. cmd/init-master.sh $host

   The first k8s node will be configured and started. You can access the k8s API on port 6443 of that host. A complete kubeconfig with cluster admin credentials is exported to cluster/admin.conf.

5. cmd/join-node.sh $host

   Add more nodes to the cluster. Only the initial node will be a master. All other nodes will not run the k8s api or host an etcd server.