Ingress and Service are two methods used to manage network traffic flow in Kubernetes, each serving a distinct purpose. A Service provides internal networking within a cluster, while Ingress manages external access to services from clients and other IT systems outside the cluster. Understanding their roles and how they complement each other is essential for optimizing your Kubernetes network architecture.
What is a Kubernetes Service?
A Service defines a logical abstraction that describes how users, applications, or other systems can access a group of Pods within a cluster. Since Pods are ephemeral and may be restarted or moved across nodes, the Service ensures stable application connectivity and prevents disruptions. There are several types of Kubernetes Services:
- ClusterIP (Default) – Exposes the Service on a cluster-internal IP. This makes the Service reachable only from within the cluster. It is the default type if no other service type is specified.
- NodePort – Exposes the Service on each Node’s IP at a static port (the NodePort). Kubernetes also sets up a cluster IP, making the Service accessible as if it were a ClusterIP.
LoadBalancer – Exposes the Service externally using an external load balancer. Kubernetes does not include a built-in load balancer, so you must provide one or integrate with a cloud provider that supports it. - ExternalName – Maps the Service to the value of the externalName field (e.g., a DNS hostname). This configures the cluster’s DNS to return a CNAME record pointing to the external hostname. No proxying is used.
What is Kubernetes Ingress?
Ingress is a higher-level method that provides an API for HTTP/HTTPS access to externally exposed services. Rather than assigning external IPs to each Service (via LoadBalancer or NodePort), Ingress consolidates access through a single entry point and routes traffic to the appropriate Service based on defined rules. Ingress understands web concepts such as hostnames, URIs, and paths. It allows you to map traffic to different backends using rules defined through the Kubernetes API.
Key Differences Between Ingress and Service
The table below compares Kubernetes Service and Ingress for traffic management:
| Kubernetes Service | Kubernetes Ingress | |
| Purpose | Internal service discovery and traffic routing | External traffic routing to services |
| Scope | Manages Traffic inside the cluster | Manages traffic from outside the cluster |
| Types | ClusterIP, NodePort, LoadBalancer | Uses Ingress Controllers (e.g. Envoy Gateway) |
| Load Balancing | Internal load balancing across Pods | HTTPS based traffic routing |
| TLS Support | Not built in – requires manual addition | Supports TLS termination for secure traffic |
How Service and Ingress Work Together
Kubernetes deployments typically use both Services and Ingress to manage traffic flow. Use a Service to enable stable internal access to a set of Pods. Use Ingress as a gateway to direct external traffic to the appropriate application or microservice based on hostname, path, or other routing rules. Modern deployments often combine Ingress with a service mesh like Istio to add advanced traffic control, security, and observability.
Optimize Kubernetes Networking with Tetrate
Designing Ingress and Service configurations can be complex. Tetrate Consulting helps organizations implement secure, scalable, and optimized Kubernetes networking architectures using Istio and advanced traffic management. Our experts can help you refine your Ingress, service mesh, and overall traffic management strategies. Connect with Tetrate’s consulting services for expert guidance on Kubernetes networking.