Introduction
Kubernetes has become the de facto standard for container orchestration, allowing developers to efficiently deploy, manage, and scale applications. Minikube provides an easy way to set up a local Kubernetes cluster for testing and learning. In this blog, we will explore the step-by-step process of deploying your first application on Kubernetes using Minikube. We will cover the fundamental concepts of Kubernetes, the installation process, pod creation, deployments, and auto-scaling.
Understanding Kubernetes Architecture
Before diving into Minikube, it's crucial to understand how Kubernetes organizes and manages applications. Let's break it down:
1. Containers
Containers provide a lightweight and portable environment for applications to run consistently across various environments. They package code, dependencies, and runtime into a single unit.
2. Pods
A Pod is the smallest deployable unit in Kubernetes. It encapsulates one or more containers that share networking and storage.
3. Deployments
A Deployment ensures that a specified number of Pods are running at all times. It supports self-healing, rolling updates, and rollback capabilities.
4. ReplicaSets
ReplicaSets manage the desired number of identical pods to ensure high availability and fault tolerance.
5. Services
Services expose a set of pods to the network, ensuring stable access despite changes in pod IP addresses.
Prerequisites
To follow along, ensure you have the following installed:
Windows with WSL2 (Ubuntu) or a Linux system
kubectl(Kubernetes CLI)Minikube (Local Kubernetes Cluster Manager)
Installing kubectl
kubectl is the command-line tool for interacting with Kubernetes clusters.
Install kubectl on Linux (x86-64):
curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
sudo install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl
Verify Installation:
kubectl version --client
Installing Minikube
Minikube is a lightweight Kubernetes cluster that runs locally.
Install Minikube:
curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
sudo install minikube-linux-amd64 /usr/local/bin/minikube
Start Minikube:
minikube start
Check Minikube Status:
minikube status
Verify Nodes:
kubectl get nodes
Deploying Pods on Kubernetes
Pods are the basic building blocks in Kubernetes. Let's deploy an Nginx pod.
Creating a Pod Configuration File
nano nginx-pod.yaml
Add the following content:
apiVersion: v1
kind: Pod
metadata:
name: nginx
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80
Deploying the Pod
kubectl apply -f nginx-pod.yaml
Verify Pod Status
kubectl get pods
Check Logs and Debug
kubectl logs nginx
kubectl describe pod nginx
Upgrading to Deployments
Deployments allow for scalability and automatic recovery from failures.
Creating a Deployment
nano nginx-deployment.yaml
Add the following content:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80
Deploying the Application
kubectl apply -f nginx-deployment.yaml
Scaling the Deployment
Increase the replicas in nginx-deployment.yaml:
spec:
replicas: 5
Apply the changes:
kubectl apply -f nginx-deployment.yaml
Checking Auto-Healing
Delete a pod and observe the auto-recovery:
kubectl delete pod <pod_name>
The system will automatically recreate the deleted pod.
Exposing Your Application
To access the application externally, expose it as a service.
kubectl expose deployment nginx-deployment --type=NodePort --port=80
Get the service details:
kubectl get svc
Find the Minikube IP and access the application:
minikube service nginx-deployment --url
Open the URL in a browser to verify the deployment.
Summary
Containers package applications with dependencies.
Pods are the smallest deployable unit in Kubernetes.
Deployments manage pods with self-healing and scaling.
Minikube allows running Kubernetes locally for development.
By following this guide, you have successfully deployed your first application on Kubernetes using Minikube! Now, experiment with rolling updates, resource limits, and monitoring for a production-ready setup.
Stay tuned for more Kubernetes tutorials!