This content originally appeared on DEV Community and was authored by Shiva Charan
Kubernetes Pods are not permanent. They can:
- restart
- scale up/down
- get recreated
- move to another node
👉 Every time a Pod is recreated, it receives a new Pod IP.
This makes Pod IPs unreliable for direct communication.
🚨 Without Services
If App A wants to talk to App B:
- App B’s Pod IP might change at any moment
- App A would immediately lose connection
- You would need to manually update IPs everywhere
This is completely unacceptable in production.
✅ So Kubernetes created “Services”
A Service gives a stable, permanent virtual IP (ClusterIP) that always points to the current healthy Pods, even if Pods keep changing.
🎯 What Is the Use of a Service?
A Kubernetes Service provides:
1️⃣ Stable Network Identity
A fixed virtual IP (VIP) for a group of Pods.
Example:
frontend → backend.default.svc.cluster.local
Even if backend pods die and get new IPs, the Service IP stays the same.
2️⃣ Automatic Load Balancing
Service uses an EndPoints / EndpointSlice list of all matching Pods:
backend-1 → 10.1.1.20
backend-2 → 10.1.2.54
backend-3 → 10.1.3.77
The Service load-balances traffic to these Pods.
3️⃣ Service Discovery
Pods do not need to know IPs; they connect using:
- DNS name
- ClusterIP
- Labels
Example:
curl http://backend
4️⃣ Exposing Pods Internally or Externally
Different Service types expose Pods at different levels:
| Service Type | Purpose |
|---|---|
| ClusterIP | Expose internally inside the cluster |
| NodePort | Expose on each node’s IP |
| LoadBalancer | Expose to the Internet (cloud LB) |
| ExternalName | Map to an external URL |
💡 Benefits of Kubernetes Services
✅ 1. Stability
Pods change constantly. Service IPs & DNS names do not.
✅ 2. Auto Load Balancing
Traffic intelligently splits across all available Pods.
✅ 3. Auto Service Discovery
Pods connect using:
service-name.namespace.svc.cluster.local
✅ 4. Health-Aware Routing
Service automatically avoids:
- unready Pods
- failing Pods
- terminating Pods
✅ 5. Decoupling of Application Layers
Frontend doesn’t need to know backend Pod IPs.
Backend doesn’t need to know DB Pod IPs.
This enables microservices.
✅ 6. Flexible Exposure Options
Choose whether Pods are:
- internal (ClusterIP)
- node-exposed (NodePort)
- internet-exposed (LoadBalancer)
- or mapped to external systems (ExternalName)
🚀 Summary — The Purpose of Services in Kubernetes
| Question | Answer |
|---|---|
| Why created? | Pods have unstable IPs; apps needed stable endpoints |
| What’s the use? | Provide stable networking, discovery, and load balancing |
| Benefits? | Stable IP, DNS, load balancing, health awareness, microservices, internal/external access |
This content originally appeared on DEV Community and was authored by Shiva Charan
Shiva Charan | Sciencx (2025-11-28T01:46:12+00:00) 🧩 Need for Services in Kubernetes.. Retrieved from https://www.scien.cx/2025/11/28/%f0%9f%a7%a9-need-for-services-in-kubernetes/
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