- You can't solve a problem just by saying techy things.
- Kubernetes.
I just needed a local Kubernetes cluster to play with. I know that one can be
quickly set up with minikube, but where is the fun with simple
minikube start?
It is going to be used for experiments, so there must be a way to set it up and tear it down with a single command. I decided to experiment with Vagrant and Ansible to create my very own, naive K3s three node cluster running inside VirtualBox.
By default three virtual machines (nodes) will be created - master and two
workers. That count can be changed by setting WORKERS_COUNT in Vagrantfile,
mind that total nodes count is equal to workers count + 1 (as there is always
k3s-node-0 acting as master).
All nodes are named according to the scheme - k3s-node-N, where N is the
node number. And IP address assigned to eth1 network interface attached to
VirtualBox private network is set to 192.168.56.(100 + N).
NOTE: If there is already host-only interface assigned to 192.168.56.0/24 address space, there can be some connectivity problems between virtual machines created by Vagrant (#1).
All was developed and tested on Debian GNU/Linux 11 (bullseye) x86_64, but I see no reason why it shouldn't work on any other distro.
Download and install:
It's as simple as calling:
vagrant up
and waiting few minutes. If the job is finished without errors, virtual machines should be created and provisioned. And cluster state can be checked with:
vagrant ssh k3s-node-0 -- 'kubectl get nodes'
which should return something like:
NAME STATUS ROLES AGE VERSION
k3s-node-0 Ready control-plane,master 54s v1.24.4+k3s1
k3s-node-2 Ready <none> 32s v1.24.4+k3s1
k3s-node-1 Ready <none> 32s v1.24.4+k3s1
When something really bad happens to the cluster or you want to start fresh - everything can be destroyed with a single command:
vagrant destroy -f
But destroying and creating virtual machines can take few minutes. If you do not want to wait that long, and there is no problem with the virtual machine or guest operating system but the cluster itself - it can be quickly purged and installed again with Ansible:
ansible-playbook reset.yml site.yml
Portainer can be installed with Ansible:
ansible-playbook portainer.yml
Installation is done when:
vagrant ssh k3s-node-0 -- 'kubectl get pods -n portainer'
shows that pod is running:
NAME READY STATUS RESTARTS AGE
portainer-5d4958459-s66fl 1/1 Running 0 34s
Portainer UI can be accessed by navigating web browser to:
- http://192.168.56.100:9000
- http://k3s-node-0.local:9000 if Avahi is running on host system