Deploying Apps on Kubernetes

1. Introduction

Kubernetes is an open-source platform designed to automate deploying, scaling, and operating application containers. This lesson covers the essential concepts and step-by-step processes for deploying applications on Kubernetes.

2. Kubernetes Concepts

Key Concepts

Pod: The smallest deployable unit in Kubernetes, a pod can contain one or more containers.
Service: An abstraction that defines a logical set of pods and a policy by which to access them.
Deployment: A resource object that provides declarative updates to applications.

3. Deployment Steps

Step-by-step Process

Create a Docker image of your application.
Push the Docker image to a container registry.
Create a Kubernetes deployment YAML file.

Tip: Use a version tag for your Docker image to manage deployments effectively.

Apply the deployment file using kubectl.
Expose your application using a service.

Example Deployment YAML

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app-container
        image: my-docker-repo/my-app:latest
        ports:
        - containerPort: 8080

4. Best Practices

Use namespaces for environment isolation.
Implement health checks for your applications.
Utilize ConfigMaps and Secrets for configuration management.

5. FAQ

What is Kubernetes?

Kubernetes is a container orchestration platform that automates deploying, scaling, and managing containerized applications.

What is a Pod in Kubernetes?

A Pod is the smallest deployable unit in Kubernetes, which can contain one or more containers that share storage and network resources.

How do you scale a Kubernetes deployment?

You can scale a deployment by changing the number of replicas in the deployment YAML or using the command kubectl scale deployment my-app --replicas=5.