Jason Meridth

I am a continuously learning senior full stack SDE/SRE trying to not let best be the enemy of better.

Raspberry Pi Kubernetes Cluster - Part 3

24 Dec 2018 » » kubernetes, raspberry pi

Raspberry Pi Kubenetes Cluster - Part 1

Raspberry Pi Kubenetes Cluster - Part 2

Raspberry Pi Kubenetes Cluster - Part 3

Raspberry Pi Kubenetes Cluster - Part 4

Well, it took me long enough to follow up on my previous posts. There are reasons.

  1. The day job has been fun and busy
  2. Family life has been fun and busy
  3. I kept hitting annoying errors when trying to get my cluster up and running

The first two reasons are the usual reasons a person doesn’t blog. :)

The last one is what prevented me from blogging sooner. I had mutliple issues when trying to use rak8s to setup my cluster. I’m a big fan of Ansible and I do not like running scripts over and over. I did read K8S on Raspbian Lite from top to bottom and realized automation would make this much better.

The issues I experienced:

apt-get update would not work

I started with the vanilla Raspbian lite image to run on my nodes and had MANY MANY issues with running apt-get update and apt-get upgrade. The mirrors would disconnect often and just stall. This doesn’t help my attempted usage of rak8s which does both on the cluster.yml run (which I’ll talk about later).

rak8s changes needed to run HypriotOS and kubernetes 1.13.1

Clone the repo locally and I’ll walk you through what I changed to get rak8s working for me and HypriotOS.

Change the following files:

  • ansible.cfg
    • change user from pi to pirate
  • roles/kubeadm/tasks/main.yml
    • add ignore_errors: True to Disable Swap task
    • I have an open PR for this here
  • group_vars/all.yml
    • Change kubernetes_package_version to "1.13.1-00"
    • Change kubernetes_version to "v1.13.1"

After you make those changes you can run ansible-playbook cluster.yml as the rak8s documentation suggests. Please note this is after you edit inventory and copy ssh keys to raspberry pis.

Flannel networking issue once nodes are up

After I get all of the nodes up I noticed the master node was marked ast NotReady and when I ran kubectl describe node raks8000 I saw the following error:

KubeletNotReady runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized

This error is known in kubernetes > 1.12 and flannel v0.10.0. It is mentioned in this issue. The fix is specifically mentioned here. It is to run the following command

kubectl -n kube-system apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml

After readin the issue it seems the fix will be in the next version of flannel and will be backported to v0.10.0.

A running cluster

Running Cluster