KoreOS

The name come from ... CoreOS and the fact that every things relative to kubernetes contains a K :D so, it's not a clever name

Prerequisites

You should know FedoraCoreOS quite well and how to write *.bu files and convert them to *.ign files : see https://docs.fedoraproject.org/en-US/fedora-coreos/producing-ign/

I'm used to rely on a PXE boot server and a Http server for provisioning and everything here is more or less based on this in mind.

You should have some k8s/kubeadm basics in your bag !

Feel free to contribute

As the first readme file everything needs to be done

This is a real WIP, I did promise it on https://discussion.fedoraproject.org/t/the-right-way-to-deploy-kubernetes-on-coreos-virtual-machines/117779/1 so I deliver my work as is

This work has been possible thanks to GOAT https://github.com/poseidon/typhoon and his great idea https://quay.io/repository/poseidon/kubelet?tab=tags&tag=latest

How to use it ?

./KoreOS/environment.conf

Contains some variables used for provisionning, change it with you favorite values, typîcally :

[Service]
Environment=KOREOS_CRIO_VERSION=v1.31.1
# https://github.com/cri-o/packaging/issues/150
Environment=LIBEXECDIR=/usr/local
Environment=KOREOS_KUBERNETES_VERSION=v1.31.2
Environment=KOREOS_CLUSTER_NAME=MyCLuster
Environment=KOREOS_DNS_DOMAIN=MyCluster.MyDomain
Environment=KOREOS_POD_SUBNET_CIDR=10.0.0.0/16
Environment=KOREOS_SERVICE_SUBNET_CIDR=10.96.0.0/12
Environment=KOREOS_HOSTNAME=%l
Environment=KOREOS_CONTROL_PLANE_ENDPOINT=mycluster.mydomain:6443

KOREOS_POD_SUBNET_CIDR and KOREOS_SERVICE_SUBNET_CIDR are default values from Kubernetes documentation.

./merge/KoreOS-dependencies-xxx.bu

These 2 files contain some other dependencies not linked to environment.conf but you should set same version numbers.

controller.bu and worker.bu

These files contain some node specific informations like storage or hostname file and the links to you http(s) server where ign files are stored/published

I don't know how to manage multiple master nodes ... feel free to contribute You will have to duplicate worker.bu for each worker node

updateignitions.sh

A small script that will convert *.bu files in *.ign files and if you want can publish them via ssh on your web server.

The right way

You should start your cluster with the master/controller node and wait for koreos-installer.service (from KoreOS-installer.ign) to finish. Then you can check the logs with journalctl -eu koreos-installer.service and get the token like kzh5ow.k7658m9zlmec5cni and the caCertHashes: like sha256:e46b74d087a9b14ebb03f7f65d75944a8dead52d0dddc654aa9878985ff9b0be

You can boot your worker nodes and then connect them via ssh and cd /opt/koreos and update the join.config.yaml with token and caCertHashes taken from master node and then run sudo kubeadm join --config join.config.yaml