Adding new nodes to Kubespray Managed Kubernetes Cluster

Kubespray is a combination of Ansible and Kubernetes and you can use Kubespray for deploying production ready Kubernetes clusters.

Read how to deploy a Kubernetes cluster using Kubespray.

You can manage full-lifecycle of Kubernetes clusters using Kubespray and in this demo we will see how to add new nodes to existing Kubernetes clusters.

(Photo by Albin Berlin from Pexels)

For the demo, we have a running kubernetes cluster with 1x master node and 2x worker nodes.

gini@greenmango kubespray % kubectl get nodes
NAME       STATUS   ROLES    AGE    VERSION
master-1   Ready    master   3h6m   v1.19.3
node-1     Ready    <none>   3h5m   v1.19.3
node-2     Ready    <none>   3h5m   v1.19.3

Step 1: Provision new Nodes

Create new nodes and make sure it is available from the machine where you have your Kubespray repository. Also configure password-less ssh key based access to new nodes.

Step 2: Update Inventory

Update inventory/mycluster/hosts.yaml with new nodes information. See below example where we have added node-3 information.

all:
  hosts:
    master-1:
      ansible_host: 192.168.50.11
      ip: 192.168.50.11
      access_ip: 192.168.50.11
    node-1:
      ansible_host: 192.168.50.21
      ip: 192.168.50.21
      access_ip: 192.168.50.21
    node-2:
      ansible_host: 192.168.50.22
      ip: 192.168.50.22
      access_ip: 192.168.50.22
    node-3:
      ansible_host: 192.168.50.23
      ip: 192.168.50.23
      access_ip: 192.168.50.23
  children:
    kube-master:
      hosts:
        master-1:
    kube-node:
      hosts:
        node-1:
        node-2:
        node-3:
    etcd:
      hosts:
        master-1:
    k8s-cluster:
      children:
        kube-master:
        kube-node:
    calico-rr:
      hosts: {}

Step 3: Run cluster.yml to add new node to cluster

gini@greenmango kubespray % ansible-playbook \
  -i inventory/mycluster/hosts.yaml \        
  cluster.yml -u devops -b -l node-3

Wait for playbook to be completed.

Also Read : 10 Tips for CKA & CKAD Exams

Step 4: Verify newly added node in Kubernetes cluster

Let us see if the nodes the added to Kubernetes cluster.

gini@greenmango kubespray % kubectl get nodes                                   
NAME       STATUS   ROLES    AGE    VERSION
master-1   Ready    master   4h9m   v1.19.3
node-1     Ready    <none>   4h8m   v1.19.3
node-2     Ready    <none>   4h8m   v1.19.3
node-3     Ready    <none>   82s    v1.19.3

Here you go, new node named node-3 is part the cluster and you can schedule workload on the same.

Learn how to deploy a Kubernetes Cluster using Kubespray.