CKA Lab Setup

Create a high availability cluster with stacked etcd.

The default configuration is:

• 3 control-planes
• 3 nodes
• 1 load balancer
• Total: 14 vCPUs, 56GB RAM

Quickstart

Install the following:

• vagrant
• VirtualBox
• ansible

$ git clone git@github.com:adamhurm/CKA_lab_setup.git
$ cd CKA_lab_setup
$ vagrant up

$ vagrant ssh cp-1
vagrant@cp-1:~$ kubectl get node -o wide
NAME     STATUS   ROLES           AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION       CONTAINER-RUNTIME
cp-1     Ready    control-plane   32m   v1.30.2   192.168.50.11   <none>        Ubuntu 22.04.4 LTS   5.15.0-113-generic   containerd://1.7.18
cp-2     Ready    control-plane   30m   v1.30.2   192.168.50.12   <none>        Ubuntu 22.04.4 LTS   5.15.0-113-generic   containerd://1.7.18
cp-3     Ready    control-plane   26m   v1.30.2   192.168.50.13   <none>        Ubuntu 22.04.4 LTS   5.15.0-113-generic   containerd://1.7.18
node-1   Ready    <none>          24m   v1.30.2   192.168.50.14   <none>        Ubuntu 22.04.4 LTS   5.15.0-113-generic   containerd://1.7.18
node-2   Ready    <none>          23m   v1.30.2   192.168.50.15   <none>        Ubuntu 22.04.4 LTS   5.15.0-113-generic   containerd://1.7.18
node-3   Ready    <none>          21m   v1.30.2   192.168.50.16   <none>        Ubuntu 22.04.4 LTS   5.15.0-113-generic   containerd://1.7.18

Once the HAProxy (cp-lb) playbook finishes, you can view the HAProxy status page: http://192.168.50.10:9999/stats/

This script will run on cp-lb to watch control-planes and add them to HAProxy config as they come online.

Customize

High Availability

The following suggested config will use 3 control-planes, 3 nodes, 1 load balancer (always). Total: 14 vCPUs, 56GB RAM

To change this behavior, edit the following values in Vagrantfile:

...
CONTROL_PLANES = 3  # >1 creates a load balancer (cp-lb)
NODES = 3
...
v.memory = 8192
v.cpus = 2

Single Control-Plane

You can also create clusters with only one control-plane.

Edit the following values in Vagrantfile to create 1 control-plane and 2 nodes:

...
CONTROL_PLANES = 1
NODES = 2
...
# allocate 2 vCPUs and 8GB RAM to each VM
v.memory = 8192
v.cpus = 2

To-do

• Automate certificate deletion. (token expires after 2 hours but this isn't ideal to leave on disk)

References

Vagrantfile template taken from this Kubernetes blog post. Updated for Ubuntu 22.04 LTS (Jammy Jellyfish).

High Availability guidance taken from these kubernetes documentation pages: kubeadm create cluster, kubeadm high availbility, kubeadm setup ha etcd