Backend Config in GKE

Published in

Niveus Solutions

2 min read4 days ago

Introduction

In Google Kubernetes Engine (GKE), the BackendConfig acts as a Custom Resource Definition (CRD) that offers enhanced control over your load balancers. Compared to using basic annotations within Ingress objects, BackendConfig provides a more structured and feature-rich approach.

Key Benefits of BackendConfig

Advanced Health Checks: Customize health check parameters such as path, port, interval, and timeout for backend services. This ensures precise health monitoring of your backend applications, going beyond the basic health checks provided by GKE Ingress.
Session Affinity: Manage user sessions with options like:
CLIENT_IP: Routes requests based on the client’s IP address, maintaining the session on the same backend instance throughout.
GENERATED_COOKIE: Injects a cookie into client responses to maintain session affinity across different backend instances. This is beneficial for applications relying on session data.
Potential Security Enhancements: Depending on your GKE version, BackendConfig may offer advanced security policies for load balancers, including access control and denial-of-service (DoS) protection.

Configuring BackendConfig in GKE

1. Enable the BackendConfig CRD

Ensure that the BackendConfig CRD is enabled in your GKE cluster. It is typically enabled by default.

2. Create a BackendConfig Resource

Define a BackendConfig resource to specify backend service settings. Below is an example configuration for custom health checks and session affinity:

apiVersion: cloud.google.com/v1

kind: BackendConfig

metadata:

spec:

healthCheck:

checkIntervalSec: 30 # Interval between health checks

timeoutSec: 10 # Timeout for each health check

healthyThreshold: 2 # Number of consecutive successes needed to mark a backend healthy

unhealthyThreshold: 2 # Number of consecutive failures needed to mark a backend unhealthy

type: HTTP # Type of health check (HTTP, HTTPS, TCP, etc.)

timeoutSec: 60 # Backend service timeout in seconds

Save this to a file named nginx-backendconfig.yaml and apply it to your cluster:

kubectl apply -f nginx-backendconfig.yaml

3. Create an Ingress Resource

Expose the service by creating an ingress resource. Here’s an example:

apiVersion: networking.k8s.io/v1

kind: Ingress

metadata:

annotations:

kubernetes.io/ingress.class: “gce”

spec:

rules:

- host: <YOUR_DOMAIN>

http:

paths:

- path: /

pathType: Prefix

backend:

service:

port:

number: 80

Replace <YOUR_DOMAIN> with your actual domain, and apply the ingress resource:

kubectl apply -f nginx-ingress.yaml

4. Verify the Configuration

Ensure the backend service uses the settings specified in the BackendConfig resource:

kubectl describe service nginx-service

kubectl describe ingress nginx-ingress

You can also verify the settings in the Google Cloud Console under the Load Balancer section.

Conclusion

Utilizing BackendConfig in GKE allows you to customize backend service settings such as health checks and timeouts. This provides greater control over your services, ensuring better performance and reliability for your applications.