Chapter 4.2 - Service Types

Learning Objectives

By the end of this chapter, you will be able to:

• Understand the 4 types of Services
• Choose the right type based on the use case
• Configure each Service type
• Understand the differences

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Service Types

Kubernetes offers 4 types of Services:

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1. ClusterIP (Default)

Internal cluster access only.

apiVersion: v1
kind: Service
metadata:
  name: clusterip-service
spec:
  type: ClusterIP  # Default
  selector:
    app: web
  ports:
  - port: 80

Use case: Inter-service communication within the cluster.

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2. NodePort

Exposes the Service on a static port on each node (30000-32767).

apiVersion: v1
kind: Service
metadata:
  name: nodeport-service
spec:
  type: NodePort
  selector:
    app: web
  ports:
  - port: 80
    targetPort: 8080
    nodePort: 30080  # Optional

Use case: External access without a cloud load balancer.

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3. LoadBalancer

Exposes via a cloud provider load balancer.

apiVersion: v1
kind: Service
metadata:
  name: loadbalancer-service
spec:
  type: LoadBalancer
  selector:
    app: web
  ports:
  - port: 80

Use case: Public-facing applications in production.

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4. ExternalName

Alias to an external service.

apiVersion: v1
kind: Service
metadata:
  name: external-service
spec:
  type: ExternalName
  externalName: database.example.com

Use case: Reference external services as if they were internal services.

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Comparison

Type	Access	IP	Port	Use Case
ClusterIP	Internal	Cluster IP	80	Internal services
NodePort	External	Node IP	30000-32767	Dev/Test
LoadBalancer	External	Cloud IP	80	Production
ExternalName	Internal	CNAME	-	External services

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Summary

In this chapter, you learned:

ClusterIP: Internal access only (default)
NodePort: Exposes on a port on each node
LoadBalancer: Via cloud load balancer
ExternalName: Alias to an external service
Choosing: Based on the use case (internal/external, dev/prod)

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Next Steps

Now that you know the types:

Chapter 4.3: Service Discovery
Lab 4.1: ClusterIP and NodePort Services

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Chapter created: December 2024