Building Highly Available Multi-regional Services on Cloud Run

16/09/2025

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Building Highly Available Multi-regional Services on Cloud Run

How to Build a Resilient Multi-Region Architecture on Cloud Run

In today’s global digital landscape, application downtime is not just an inconvenience; it’s a direct threat to user trust and revenue. While deploying on a serverless platform like Cloud Run offers incredible scalability and ease of use, a single-region deployment still leaves you vulnerable to localized outages. The key to achieving true resilience and providing a fast, reliable experience for all users lies in a multi-regional architecture.

This guide will walk you through the essential concepts and steps for building a highly available, multi-region service on Cloud Run, ensuring your application remains online and performant, even if an entire cloud region experiences a disruption.

The Risk of a Single-Region Deployment

Deploying your application to a single geographic region, such as us-central1, is straightforward but carries inherent risks:

Single Point of Failure: If that specific region suffers an outage due to a network issue, hardware failure, or natural disaster, your application goes down with it.
Increased Latency: Users located far from your chosen region will experience slower response times, negatively impacting their experience. A user in Europe accessing a service hosted solely in the US will always face higher latency than one accessing a server in a nearby European data center.

A multi-regional strategy directly addresses these challenges by distributing your application across the globe, creating a robust and responsive system.

The Core Components for a Multi-Region Setup

Achieving a seamless multi-region deployment on Google Cloud involves orchestrating three key components that work together to intelligently route traffic and ensure high availability.

Multiple Cloud Run Services: This is the foundation. You will deploy identical versions of your containerized application as separate Cloud Run services in different geographic regions (e.g., one in North America, one in Europe, and another in Asia).
Serverless Network Endpoint Groups (NEGs): A Serverless NEG acts as a pointer or a connector to a specific serverless service like Cloud Run. You will create one Serverless NEG for each regional Cloud Run service you deploy. This allows the load balancer to recognize your serverless instances as valid backends.
Global External HTTPS Load Balancer: This is the brain of the operation. This global load balancer provides a single, static IP address for your users worldwide. It intelligently directs incoming traffic to the closest healthy Cloud Run instance, providing both low latency and automatic failover.

A Step-by-Step Guide to Implementation

Building this architecture involves configuring these components to work in harmony. Here’s a high-level overview of the process.

Step 1: Deploy Your Application to Multiple Regions

First, take your containerized application and deploy it as a Cloud Run service in each of your target regions. For example, you might deploy the same container image to:

my-app-us in the us-central1 region
my-app-eu in the europe-west1 region

Ensure that each service is configured correctly and can run independently.

Step 2: Create a Serverless NEG for Each Service

For the Global Load Balancer to send traffic to your Cloud Run services, you must make them “visible” as backends. This is done by creating a Serverless NEG in each region that points to the respective Cloud Run service.

Create my-neg-us in us-central1 and associate it with the my-app-us Cloud Run service.
Create my-neg-eu in europe-west1 and associate it with the my-app-eu Cloud Run service.

Step 3: Configure the Global External HTTPS Load Balancer

This is the most involved step, where you tie everything together.

Create Backend Services: A backend service defines how the load balancer distributes traffic and performs health checks. You will create a global backend service and add both your Serverless NEGs (my-neg-us and my-neg-eu) to it.
Configure Health Checks: This is critical for failover. A health check periodically pings your services to ensure they are responding correctly. If the health check for the us-central1 service fails, the load balancer will automatically stop sending traffic to it and route all requests to the healthy europe-west1 instance until the US service recovers.
Set Up Routing Rules: The URL map defines how requests are routed. For a simple setup, you’ll configure it to send all traffic for your domain (e.g., www.yourapp.com) to the backend service you just created.
Configure the Frontend: This is the public-facing part of the load balancer. You’ll reserve a global static IP address and create an HTTPS forwarding rule. You will also need to attach an SSL certificate to handle encrypted traffic. Google-managed SSL certificates are an excellent, low-maintenance option for this.

Once the DNS for your domain is pointed to the load balancer’s static IP address, the setup is complete.

Key Benefits of This Architecture

Implementing a multi-region Cloud Run architecture delivers significant advantages for any serious application.

Automatic Failover and High Availability: If one region goes offline, the load balancer’s health checks will detect the failure and reroute 100% of the traffic to the healthy regions with no manual intervention required. This is the cornerstone of disaster recovery.
Reduced Latency and a Better User Experience: The global load balancer automatically sends users to the Cloud Run instance geographically closest to them. This minimizes network travel time, resulting in a faster, more responsive application for your entire user base.
Simplified Global Scalability: Because Cloud Run is serverless, you don’t have to manage any underlying VMs or infrastructure. Scaling is handled automatically within each region, and the load balancer manages global traffic distribution seamlessly.

Essential Security and Best Practices

To further harden your deployment, consider these additional tips:

Secure Your Backends: Configure your Cloud Run services to only allow ingress traffic from the Global External HTTPS Load Balancer. This prevents users from bypassing the load balancer and accessing a regional service directly.
Implement Robust Monitoring: Use Cloud Monitoring to set up alerts on your load balancer’s health checks and backend service health. This will ensure you are notified immediately if a region becomes unhealthy.
Use Infrastructure as Code (IaC): Define your entire setup using a tool like Terraform. This makes your architecture repeatable, version-controlled, and less prone to human error during configuration.

By moving beyond a single-region deployment, you transform your Cloud Run application from a simple service into a globally resilient, high-performance platform prepared for scale and resilient against failure.

Source: https://cloud.google.com/blog/topics/developers-practitioners/how-to-build-highly-available-multi-regional-services-with-cloud-run/