I love decentralized computing. It’s beautiful. Just add a node to your cluster if you need more power! Just that. Restart the pods with no downtime, horizontal pod autoscaler...

To create a cluster, we can do it with services provided by google, amazon… or just manually installing it in each node.

I prefer to create my own mini cluster. My cluster is made of 6 raspberry pi 4B (4GB RAM each) and has it's own name: clusperry ⚡️

I created a simple gui tool to generate the linux images to flash into the mini-SD cards with the initial cloudconfig. You can check it here: https://github.com/nullxx/clusperry-installer.

Nodes setup

Download the release from https://github.com/nullxx/clusperry-installer/releases/ (its currently only compiled for macOS)

1. Select the nodes operating system

2. Configure each node with your configuration:

• IP
• WIFI (or ethernet)
• hostname
• SSH keys

3. Download OS images

4. Write images

5. Open generated images

Install kubernetes with k3s

For this I will use ansible. It makes it easier to do all the install work.
I will use the following repo: https://github.com/k3s-io/k3s-ansible

Clone the repo

git clone https://github.com/k3s-io/k3s-ansible.git 

Get into the cloned repo

cd k3s-ansible 

Create our inventory from the sample

cp -R inventory/sample inventory/my-cluster 

Edit inventory/my-cluster/hosts.ini

nano inventory/my-cluster/hosts.ini 

[master] 192.168.1.100 [node] 192.168.1.101 192.168.1.102 192.168.1.103 192.168.1.104 192.168.1.105 [k3s_cluster:children] master node 

Edit inventory/my-cluster/group_vars/all.yml

In my case edit the ansible_user to ubuntu

--- k3s_version: v1.17.5+k3s1 ansible_user: ubuntu systemd_dir: /etc/systemd/system master_ip: "{{ hostvars[groups['master'][0]]['ansible_host'] | default(groups['master'][0]) }}" extra_server_args: "" extra_agent_args: "" 

Be ready for the power!

Execute the ansible-playbook to install k8s in the nodes.

ansible-playbook site.yml -i inventory/my-cluster/hosts.ini 

Install kubectl in your computer

In my case macOS

brew install kubectl 

Get the kubectl config from any of your master nodes

scp ubuntu@192.168.1.100:~/.kube/config ~/.kube/config 

Verify installation.

Check that all nodes are in STATUS 'Ready'

kubectl get nodes 

Deploy test

Create a local DNS entry for the test

sudo echo "192.168.1.100 test.com" >> /etc/hosts 

I'm going to use traefik because is installed by default with k3s.

apiVersion: apps/v1 kind: Deployment metadata: name: nginx-deployment spec: selector: matchLabels: app: nginx replicas: 2 # tells deployment to run 2 pods matching the template template: metadata: labels: app: nginx spec: containers: - name: nginx image: nginx:1.14.2 ports: - containerPort: 80 --- apiVersion: v1 kind: Service metadata: name: nginx-service labels: name: nginx-service spec: ports: - port: 80 name: http selector: name: nginx-deployment --- apiVersion: extensions/v1beta1 kind: Ingress metadata: name: nginx-ingress annotations: kubernetes.io/ingress.class: traefik spec: rules: - host: "test.com" http: paths: - path: / backend: serviceName: nginx-service servicePort: 80 

 Verify pods are up

kubectl get pods 

Go to http://test.com on your browser

curl http://test.com 

Its working!

Cleanup

Remember to remove the test.com line in /etc/hosts

Persistent storage

Part two available here