Kubeup

Simple Kubernetes cluster creator based on kubeadm for libvirt (Linux). Default setup is a single master with three nodes

Requirements

Install qemu-kvm, libvirt

Ubuntu

sudo apt install qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils

Fedora

sudo dnf -y install qemu-kvm libvirt

CentOS 7

• Run the following:

sudo yum install epel-release
sudo yum install qemu libvirt qemu-kvm

Usage

Add your user to libvirt group

sudo usermod -a -G libvirt $(whoami)

This will allow the up.sh script to run without sudo later on.

You may also need to restart libvirtd to pick up the change.

sudo systemctl restart libvirtd.service

Create global_vars.yml

If you have not already done so, create global_vars.yml:

$ cp global_vars.yml.tmpl global_vars.yml

Edit global_vars.yml accordingly, then to create the cluster, type:

$ ./up.sh

The Kubernetes configuration is then copied from the master node to the host and can be used as follows:

$ kubectl --kubeconfig=kubeconfig-k8s1.conf get nodes
NAME                  STATUS   ROLES    AGE     VERSION
lpabon-k8s-1-master   Ready    master   8m12s   v1.19.5
lpabon-k8s-1-node0    Ready    <none>   7m44s   v1.19.5
lpabon-k8s-1-node1    Ready    <none>   7m44s   v1.19.5
lpabon-k8s-1-node2    Ready    <none>   7m45s   v1.19.5

kubeup script

Kubeup uses a container to run vagrant and vagrant-libvirt. For convenience a script called kubeup has been provided.

Use this script to prefix all your vagrant commands. For example:

$ ./kubeup vagrant ssh lpabon-k8s-1-node0

Exporting

Kubeup informs kubeadm to create a cert with the addition of the IP of the host. This will allow you to forward a port from the host to the Kubernetes cluster running on the VM allowing access from the external host network.

You will need to do the following once the cluster is running:

1. Use socat to forward a port from the host to the VM:

socat TCP-LISTEN:6443,fork,reuseaddr TCP:<IP of master>:6443

2. Edit the kubeconfig-k8s1.conf generated and change the server ip from the VM's ip to the ip of the host.

Using a local Docker registry

It may be necessary to setup your own registry for your images. Not only will this keep your images private, but it will also make it accessible by Kubernetes faster, since the images are pulled over a local host network.

Follow the instructions in Deploying a local registry server to deploy your docker registry on your host machine. This registry can only be accessed over localhost. Docker clients running in the Kubernetes VMs will not be able to access the registry directly. For this reason, kubeup sets up a tunnel service from each VM to the docker registry. This service uses socat to allow the docker client to access your custom registry without HTTPS.

Set the following variables in global_vars.yml:

docker_localregistry: true
docker_localregistry_host: <host ip address running docker registry>
docker_localregistry_port: <port of docker registry>