Deploy kubernetes cluster in minutes with k3s

K3S is a lightweight and certified Kubernetes distribution, perfect for run development environments, CI/CD and IoT. It works very well with the ARM architecture. It’s packaged to a single binary that makes deployment and setup easy.

The default installation comes with:

• embedded SQLite
• containerd
• flannel
• coredns
• traefik (ingress controller)
• local path provisioner
• service load balancer

All those features are more than enough for most use-cases. Of course, installation is fully configurable, so if you want etcd, docker, Nginx ingress and so on – go to official documentation page https://rancher.com/docs/k3s/latest/en/ .

Default installation

Login to machine and run:

curl -sfL https://get.k3s.io | sh -

and that’s it… After a few seconds, you should see that the master node is ready with k3s kubectl get node.

You will find config.yaml for kubernetes in /etc/rancher/k3s/k3s.yaml

Advanced installation with nginx-ingress, metallb and cert-manager

1. Deploy k3s without traefik and servicelb

   curl -sfL https://get.k3s.io | K3S_KUBECONFIG_MODE="644" INSTALL_K3S_EXEC=" --no-deploy=servicelb --no-deploy=traefik" sh -s -
   

2. Get config from /etc/rancher/k3s/k3s.yaml and put into ~/.kube/config on your machine

3. Install helm

   curl https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3 | bash
   

4. Add helm repo and update

   helm repo add stable https://kubernetes-charts.storage.googleapis.com/
   helm repo update
   

5. Install metallb. Range of available ip addresses for loadbalancer are set in configInline.address-pools[0].addresses[0].

   helm install --namespace=kube-system 
     --set configInline.address-pools[0].name=default 
     --set configInline.address-pools[0].protocol=layer2 
     --set configInline.address-pools[0].addresses[0]=192.168.1.10-192.168.1.50 
     metallb stable/metallb
   

6. Install nginx-ingress

   helm install --namespace=kube-system 
       --set rbac.create=true 
       nginx-ingress stable/nginx-ingress
   

7. Install and configure certmanager for lets-encrypt

   kubectl apply -f https://raw.githubusercontent.com/jetstack/cert-manager/release-0.14/deploy/manifests/00-crds.yaml
   helm install --namespace=kube-system cert-manager stable/cert-manager
   cat <<EOF | kubectl apply -f -
   apiVersion: cert-manager.io/v1alpha2
   kind: ClusterIssuer
   metadata:
     name: letsencrypt
   spec:
     acme:
       server: https://acme-v02.api.letsencrypt.org/directory
       email: ACME_EMAIL
       privateKeySecretRef:
         name: letsencrypt
       solvers:
         - dns01:
             cloudflare:
               email: CLOUDFLARE_EMAIL
               apiKeySecretRef:
                 name: cloudflare-apikey-secret
                 key: CLOUDFLARE_APIKEY
           selector:
             dnsNames:
               - 'DOMAIN_NAME'
   EOF
   

   Where:

   • ACME_EMAIL – some email in yor domain (will be used to limit number of requests to acme)
   • CLOUDFLARE_EMAIL – email of your cloudflare account
   • CLOUDFLARE_APIKEY – api key to your cloudflare acccount
   • DOMAIN_NAME – domain that will be used in lets-encrypt certs (eg.: *.rycerz.co)

Important disclaimer

Don’t deploy everything in kube-system if it’s not test/development cluster. Be safe.