Introduction

In Kubernetes, an ingress object is used to provide HTTP and HTTPS routing to services within a cluster. It defines rules for routing external requests to backend services based on URL paths or hostnames. Sometimes, there is a need to route requests from multiple domains or paths to the same service. This article delves into configuring multiple ingress objects for a single Kubernetes service, exploring the nuances, technical details, and practical examples involved in the process.

Basics of Kubernetes Ingress

Ingress is an API object that manages external access to services, typically over HTTP and HTTPS. Features of ingress include:

• Exposing multiple services under a single IP address.
• Load balancing.
• SSL/TLS termination.
• Name-based virtual hosting.

Key Components of Ingress

• Ingress Controller: This is a daemon that watches for ingress resources and configures its underlying load balancer to implement these rules.
• Ingress Resource: This is the set of configurations for routing rules including paths and hostnames.

The Concept of Multiple Ingress Objects

To facilitate extensive routing configurations or distinct domain management, multiple ingress objects can be used for a single service. Here are a few common scenarios:

• Different Domains: You want `foo.com` and `bar.com` to point to the same service.
• Path-based Routing: You want `/api/v1/` and `/api/v2/` to point to a versioned API service.
• Separation of Concerns: Administratively or logically managing multiple ingress rules separately for simplicity or different teams.

Advantages

1. Modularity: Break down complex routing into manageable parts.
2. Scalability: Easily add new rules without altering existing configurations.
3. Security: Isolate configurations based on teams or permissions.

Implementing Multiple Ingress Objects

Prerequisites

• A working Kubernetes cluster.
• An ingress controller (e.g., NGINX, Traefik) installed and configured.
• A service deployed in the cluster that you want to expose.

Creating Multiple Ingress Objects

In this example, we will create two ingress objects to point to a service named `my-service` running on port 80. The service is exposed to two domains: `example.com` and `example.net`.

1. Ingress for `example.com`
   • host: example.com
     • path: /
   • host: example.net
     • path: /