Deploy Kubernetes Add-ons: Statically and Dynamically

Kubernetes, the powerful container orchestration platform, allows for the seamless deployment and management of containerized applications. To enhance the functionality and capabilities of your Kubernetes cluster, deploying add-ons is essential. In this article, we will explore two methods of deploying Kubernetes add-ons: statically and dynamically.

Statically Deploying Kubernetes Add-ons:

Step 1: Understand Statically Deployed Add-ons

Statically deployed add-ons are included during the initial setup of the Kubernetes cluster. These add-ons are typically specified in the cluster configuration and are deployed automatically when the cluster is brought online.

Step 2: Review Common Statically Deployed Add-ons

Some common statically deployed add-ons include:

• Kube-dns: Provides DNS-based service discovery within the cluster.
• Dashboard: A web-based UI for visualizing and managing the cluster.
• Kube-proxy: Maintains network rules on nodes.

Step 3: Example Configuration

Here is an example YAML configuration for statically deploying kube-dns:

apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: 10.0.0.10
  ports:
    - protocol: UDP
      port: 53
      targetPort: 53
    - protocol: TCP
      port: 53
      targetPort: 53

Dynamically Deploying Kubernetes Add-ons:

Step 4: Understand Dynamically Deployed Add-ons

Dynamically deployed add-ons are installed or upgraded after the Kubernetes cluster is running. Helm, a package manager for Kubernetes, is commonly used for dynamic add-on deployments.

Step 5: Install Helm

To deploy add-ons dynamically, start by installing Helm:

curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3
chmod 700 get_helm.sh
./get_helm.sh

Step 6: Example Helm Chart

Create a Helm chart for an add-on, for example, Nginx-ingress:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-ingress
  namespace: ingress
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx-ingress
  template:
    metadata:
      labels:
        app: nginx-ingress
    spec:
      containers:
      - name: nginx-ingress-controller
        image: nginx/nginx-ingress:latest
        ports:
        - containerPort: 80

Step 7: Deploying with Helm

Use Helm to deploy the Nginx-ingress add-on:

helm install nginx-ingress ./nginx-ingress-chart

So, deploying Kubernetes add-ons adds essential functionality to your cluster. Statically deployed add-ons are configured during the cluster setup, while dynamically deployed add-ons can be managed post-deployment using tools like Helm. Understanding and utilizing both methods allows for a flexible and feature-rich Kubernetes environment.