kubectl apply vs create in Kubernetes - Hands-On Comparison

Understanding kubectl apply vs create

📖 Scenario: You are managing a Kubernetes cluster. You want to deploy an application using YAML files. You need to understand the difference between kubectl create and kubectl apply commands to manage your resources effectively.

🎯 Goal: Learn how to create a Kubernetes deployment using kubectl create and then update it using kubectl apply. See how these commands behave differently when managing resource changes.

📋 What You'll Learn

Create a Kubernetes deployment YAML file named nginx-deployment.yaml with specified content

Use kubectl create to create the deployment from the YAML file

Modify the YAML file to change the number of replicas

Use kubectl apply to update the deployment with the new replica count

Observe the output of both commands

💡 Why This Matters

🌍 Real World

Kubernetes is widely used to deploy and manage containerized applications. Knowing how to create and update resources with kubectl commands is essential for daily cluster operations.

💼 Career

DevOps engineers and site reliability engineers use these commands to manage application deployments, updates, and rollbacks in production environments.

1

Create the initial deployment YAML file

Create a file named nginx-deployment.yaml with the exact content below:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

Kubernetes

# Create the file nginx-deployment.yaml with the exact content
# Your code here

Need a hint?

Use a text editor to create nginx-deployment.yaml with the exact YAML content.

2

Create the deployment using kubectl create

Run the command kubectl create -f nginx-deployment.yaml to create the deployment in your Kubernetes cluster.

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

# Run kubectl create command below
# Your code here

Need a hint?

Type exactly kubectl create -f nginx-deployment.yaml to create the deployment.

3

Modify the deployment YAML to change replicas

Edit the nginx-deployment.yaml file to change the replicas value from 2 to 3.

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

# Change replicas from 2 to 3 below
# Your code here

Need a hint?

Open the YAML file and change the line replicas: 2 to replicas: 3.

4

Update the deployment using kubectl apply

Run the command kubectl apply -f nginx-deployment.yaml to update the deployment with the new replica count. Then run kubectl get deployment nginx-deployment to see the updated replicas.

Kubernetes

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:1.14.2
        ports:
        - containerPort: 80

# Run kubectl apply and then kubectl get deployment commands below
# Your code here

Need a hint?

Type exactly kubectl apply -f nginx-deployment.yaml and then kubectl get deployment nginx-deployment.