Skip to main content

Your First Deployment: Hello World

Key Takeaways for AI & Readers
  • Deployment Object: Creating a deployment triggers a chain reaction: Deployment -> ReplicaSet -> Pod.
  • Service Exposure: Pods are isolated by default; a Service (e.g., NodePort) is required to expose them to traffic.
  • Observability: Standard commands like get, describe, and logs are essential for verifying the state of your application.

Enough theory—let's deploy an application. We will use kubectl to create a Deployment and expose it to the network.

1. Interactive Terminal Simulation​

Follow the steps below to see the standard workflow for launching a containerized app.

bash — 80x24
$ kubectl get pods
No resources found in default namespace.
_

2. What just happened?​

kubectl create deployment​

This command didn't just start a container. It created a Deployment object in the API Server. The Controller Manager then noticed the new object and created a ReplicaSet, which finally created the Pod.

kubectl expose​

By default, Pods are isolated. To allow traffic to reach them, we created a Service. In this case, we used Type: NodePort, which opens a specific port on the physical node's IP address.

3. Verification Commands​

  • kubectl get all: See everything you just created.
  • kubectl describe pod <name>: Deep dive into the container status and events.
  • kubectl logs <name>: Read the output from the application.