k8s.github.io

Boot up controlplane

To create a highly available control plane, we install kubeadm on the first control plane node almost the same way as for a single control plane cluster, then we join the other control plane nodes in a similar manner to joining worker nodes

controlplane01

1. ssh to controlplane01

   ssh controlplane01
   

2. Become root

    sudo -i
   

3. Set shell variable for the pod network CIDR.

   POD_CIDR=192.168.0.0/16
   

4. Boot the first control plane using the IP address of the load balancer as the control plane endpoint

   Set a shell variable to the IP of the loadbalancer

    LOADBALANCER=$(dig +short loadbalancer)
   

   …and install Kubernetes using --control-plane-endpoint and --upload-certs which instructs it that we are building for multiple controlplane nodes.

    kubeadm init --pod-network-cidr $POD_CIDR \
        --control-plane-endpoint ${LOADBALANCER}:6443 \
        --upload-certs
   

   Copy both join commands that are printed to a notepad for use on other control nodes and the worker nodes.

5. Install network plugin (calico). Weave does not work too well with HA clusters.

    kubectl --kubeconfig /etc/kubernetes/admin.conf create -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.3/manifests/tigera-operator.yaml
    kubectl --kubeconfig /etc/kubernetes/admin.conf create -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.3/manifests/custom-resources.yaml
   

6. Check we are up and running

   kubectl --kubeconfig /etc/kubernetes/admin.conf get pods -n kube-system
   

7. Exit root shell

   exit
   

8. Prepare the kubeconfig file for copying to student-node node, which is where we will run future kubectl commands from.

   {
     sudo cp /etc/kubernetes/admin.conf .
     sudo chmod 666 admin.conf
   }
   

9. Exit to student-node

   exit
   

10. On student-node, Copy down the kubeconfig so we can run kubectl commands from student-node

    ```bash { mkdir ~/.kube scp controlplane01:~/admin.conf ~/.kube/config }

controlplane02 and controlplane03

Be on student-node

For each of controlplane02 and controlplane03

1. SSH to controlplane02

2. Become root

   sudo -i
   

3. Paste the join command for control nodes that was output by kubeadm init on controlplane01
4. Exit back to student-node

   exit
   exit
   

5. Repeat the steps 2,3 and 4 on controlplane03

Next: Worker setup</br> Prev: Node Setup