Day-38-devops

TLDR: This blog post provides an in-depth exploration of Kubernetes Ingress, explaining its necessity, functionality, and practical implementation. It addresses common challenges faced by users transitioning from traditional load balancers to Kubernetes, and outlines how Ingress solves these issues through enhanced load balancing capabilities and cost efficiency.

Today marks Day 38 of our complete DevOps course, where we will delve into the concept of Kubernetes Ingress. Many find this topic challenging due to two main reasons: a lack of understanding of its necessity and difficulties in practical implementation. In this post, we will clarify these points and provide a detailed guide on both the theory and practical aspects of Kubernetes Ingress.

What is Ingress?

Before we dive into the details, let’s clarify what Ingress is. Ingress is a Kubernetes resource that manages external access to services within a cluster, typically HTTP. It provides a way to route traffic to different services based on the request's URL path or host.

Why is Ingress Required?

To understand the necessity of Ingress, we need to look at the limitations of Kubernetes services:

1. Limited Load Balancing Features: While Kubernetes services provide basic load balancing through round-robin methods, they lack advanced features found in traditional enterprise load balancers. These features include:

   • Ratio-based load balancing

   • Sticky sessions

   • Path-based and host-based routing

   • Whitelisting and blacklisting capabilities

   • TLS termination and security features

2. Cost Implications: When using a service of type LoadBalancer, cloud providers charge for each static IP address allocated. For organizations with numerous services, this can lead to significant costs.

Historical Context

Before the introduction of Ingress in Kubernetes version 1.1, users relied solely on services for managing traffic. However, as organizations migrated from traditional virtual machines to Kubernetes, they quickly realized the limitations of the service model. Users were accustomed to the rich feature set of enterprise load balancers, which Kubernetes services did not replicate.

How Ingress Solves These Problems

Kubernetes recognized these challenges and introduced Ingress to address them. Here’s how Ingress resolves the issues:

• Enhanced Load Balancing Capabilities: Ingress allows users to define rules for routing traffic, enabling features like path-based routing and host-based routing, which were previously unavailable.

• Cost Efficiency: Instead of creating a separate LoadBalancer service for each application, Ingress allows multiple services to share a single IP address, significantly reducing costs.

Ingress Controllers

To utilize Ingress, users must deploy an Ingress controller. This controller is responsible for processing Ingress resources and managing the routing of traffic. Popular Ingress controllers include:

• NGINX Ingress Controller

• HAProxy Ingress Controller

• Traefik

• Ambassador

How to Set Up Ingress

1. Deploy an Ingress Controller: Choose an Ingress controller based on your requirements. For example, to deploy the NGINX Ingress controller on a Minikube cluster, you can use the command:

    minikube addons enable ingress
   

2. Create an Ingress Resource: Define an Ingress resource in a YAML file. Here’s a basic example:

    apiVersion: networking.k8s.io/v1
    kind: Ingress
    metadata:
      name: example-ingress
    spec:
      rules:
      - host: food.bar.com
        http:
          paths:
          - path: /bar
            pathType: Prefix
            backend:
              service:
                name: my-service
                port:
                  number: 80
   

3. Apply the Ingress Resource: Use the following command to apply the Ingress resource:

    kubectl apply -f ingress.yaml
   

4. Verify the Setup: Check if the Ingress resource is created and the address field is populated:

    kubectl get ingress
   

5. Update Hosts File (Local Testing): If you are testing locally, update your /etc/hosts file to map the domain to the Minikube IP address:

    192.168.64.11 food.bar.com
   

Practical Implementation

In the practical part of this session, we will demonstrate how to create an Ingress resource and configure it to route traffic based on host and path. We will also explore how to enable TLS for secure connections.

Conclusion

In this post, we have explored the concept of Kubernetes Ingress, its necessity, and how it enhances the capabilities of Kubernetes services. By understanding the problems Ingress solves and how to implement it, you can effectively manage external access to your applications in a Kubernetes environment. For a more hands-on experience, I encourage you to watch the detailed practical video linked in the description.

If you found this information helpful, please like and comment on the video. I look forward to seeing you in the next session. Take care!