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

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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.

Gineesh Madapparambath

Gineesh Madapparambath is the founder of techbeatly. He is the co-author of The Kubernetes Bible, Second Edition and the author of Ansible for Real Life Automation. He has worked as a Systems Engineer, Automation Specialist, and content author. His primary focus is on Ansible Automation, Containerisation (OpenShift & Kubernetes), and Infrastructure as Code (Terraform). (Read more: iamgini.com)

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