Introduction to GKE and Load Balancers

Google Kubernetes Engine (GKE) is a managed service offered by Google Cloud Platform (GCP) that allows you to run Kubernetes clusters within the Google infrastructure. One of the critical aspects of deploying applications on GKE is serving traffic securely over HTTPS, typically achieved using load balancers.

This article will guide you through the process of serving HTTPS content via the Layer 7 (L7) load balancer in GKE. We'll delve into the technical workings, configurations, and examples to help you understand and implement it.

What is a Layer 7 Load Balancer?

Layer 7 load balancers operate at the application layer of the OSI model. They can make intelligent routing decisions based on the content of the HTTP request. In the context of GKE, a Layer 7 load balancer is an HTTP(S) load balancer that can distribute incoming HTTPS traffic across multiple backend instances.

Why Use an L7 Load Balancer?

• Advanced Routing: Direct traffic based on URL paths and headers.
• SSL Termination: Manage SSL certificates centrally, simplifying the deployment of HTTPS.
• Global Load Balancing: Efficiently distribute traffic to multiple regions.
• Improved Security: Add another layer of protection through web application firewall integrations and DDoS protection.

Setting Up HTTPS on GKE with L7 Load Balancer

Setting up HTTPS on GKE involves several steps, each integrating various Google Cloud services. Here's a step-by-step on how to accomplish this:

1. Prepare Your GKE Cluster

Before configuring a load balancer, ensure your GKE cluster and workloads are properly set up and running. Deploy your Kubernetes application with appropriate services and workloads.

2. Provision a Managed SSL Certificate

1. Create a ManagedCertificate Resource: Use the Kubernetes `ManagedCertificate` CRD (Custom Resource Definition) to define the domains for which you need HTTPS certificates.
   • example.com
   • www.example.com
   • host: example.com
     • path: /

• Enable Cloud Armor: It offers DDoS protection and additional security policies.
• IAM Roles and Policies: Secure your cluster's operations by providing least privileged access.