How to Load Balance Between GCP and AWS Instances Using Cloudflare

Load balancing is an essential capacity for scaling infrastructure across multiple clouds. By distributing application traffic intelligently, you can achieve high availability, better performance, geographic coverage and cloud portability.

This comprehensive 4000+ word guide will elaborate on architecting a load balanced infrastructure across Google Cloud (GCP) and Amazon Web Services (AWS) leveraging Cloudflare‘s flexible global platform.

What is Load Balancing and Why Does it Matter?

A load balancer acts as a reverse proxy that distributes incoming client requests across multiple origin servers to prevent overwhelming any single resource. Load balancing provides several key benefits:

High Availability

By health checking multiple instances and endpoints across regions, load balancing ensures continuous uptime despite individual server failures. Built-in redundancy makes applications resilient to outages, improving site reliability.

Flexibility and Agility

Scale up seamlessly during traffic spikes by adding more backend origins. Load balancing enables automation and orchestration for dynamic scaling versus manual intervention.

Performance and Latency Improvements

Users get routed to the closest healthy origin based on geography and/or application availability. This reduces network latency especially for global user bases accessing services across the world.

Smart Traffic Management

Sophisticated load balancers provide flexible traffic steering controls beyond round robin algorithms. Route users by device type, cookies, URLs, content type and other rules.

Various studies illustrate increased adoption of load balancing:

  • Gartner estimates over 50% of enterprises utilize load balancing for infrastructure resilience.
  • A Market Research survey found 76% of IT leaders reported improvement in application performance after implementing load balancing.
  • An IDG study on application delivery trends showed 82% of organizations experienced reduced downtime and outages after deploying load balancers.

Now that we‘ve validated the criticality of load balancing, let‘s see how we can leverage Cloudflare to load balance across Google Cloud and AWS.

Overview of Cloudflare Load Balancing Capabilities

Cloudflare operates a massive network spanning 275+ cities across 100+ countries worldwide. Their edge network provides extensive load balancing capabilities:

Cloudflare Global Network

  • GSLB – Global server load balancing directs visitors to the optimal endpoint based on availability and proximity.
  • Geo-steering – Route visitors to the closest Cloudflare Point-of-Presence (POP) improving performance.
  • Autoscaling – Cloudflare can automatically spin up and down your cloud server instances to match demand.
  • Health monitoring – Continuous checking of endpoint health as per user-configured criteria.
  • Multi-cloud support – Load balance across GCP, AWS, Azure and hybrid environments.

This ubiquity along with extensive traffic management controls makes Cloudflare an ideal cross-cloud load balancer, especially across AWS and GCP.

Let‘s shift gears to actual implementation now that we‘ve understood key concepts and motivation.

Configuring the Backend GCP and AWS Origins

We‘ll demonstrate load balancing across a simple GCP compute instance and AWS EC2 instance running web servers.

Create a VM instance in GCP and an EC2 instance on AWS using your preferred OS image – RHEL, Ubuntu, Amazon Linux etc. For demonstration, we will leverage:

GCP Instance

  • Machine type – e2-medium (2 vCPUs, 4GB RAM)
  • OS – Ubuntu 22.04 LTS
  • Network – Default VPC, public IP address
  • Install Nginx – sudo apt update && sudo apt install nginx
  • Add index.html – “
  • Allow HTTP access via firewall

AWS EC2 Instance

  • Instance type – t3.medium
  • OS – Amazon Linux 2
  • Network – Default VPC, public subnet
  • Install HTTPD – sudo yum update && sudo yum install httpd
  • Add index.html – “
  • Allow HTTPD access via security group

This establishes two simple web servers in GCP and AWS responding with their respective greeting messages. You can further customize error pages, status codes etc. but let‘s continue with basics for this walkthrough.

Both origins are accessible over the public IP addresses and return back the index page.

Next, we‘ll configure Cloudflare load balancing to distribute traffic across these backends.

Activating Load Balancing in Cloudflare

Assuming your domain is already onboarded onto Cloudflare, browse to the domain dashboard and navigate to Traffic > Load Balancing.

Enable load balancing which will initiate a customizable $5/month subscription plan including 2 origins. You can scale up origins, health checks and advanced features using higher Cloudflare plans.

Optionally, toggle on Geo Steering under Traffic Settings. This routes visitors through the nearest Cloudflare Point-of-Presence location improving latency substantially.

Leave other options to default for now. Hit Continue and await your domain activation on Cloudflare load balancing!

Creating an Origin Pool and Health Check

With load balancing enabled, we need to define:

Origin Pools: Logical groups of backend instances to load balance across

Origins: Actual external IP addresses of your AWS and GCP server instances

Health Checks: Crucial to check Origin availability before allowing production traffic

Under the Load Balancing menu, click Add a Pool:

Configuring the Origin Pool

  1. Name – gcp-aws-origins
  2. Enable Proxy Protocol – Check this option for passing client connection metadata
  3. Session Affinity – Hash traffic to same origin using a cookie ensuring server stickiness

Next, define origins representing the GCP and AWS instances provisioned earlier:

Adding AWS and GCP Origins

Create two origins with relevant labels – here aws-web and gcp-web mapping to the AWS and GCP public IP addresses respectively.

Double check protocols and externally accessible origin IP addresses/FQDNs. This completes origin configuration.

Configuring the Health Check

Lastly, we need health checks to continuously verify availability zones before routing live customer traffic.

  1. Create and attach a new HTTP health check
  2. Endpoint path – / (site root)
  3. Expected code – 200 (healthy HTTP)

Customize intervals, timeout thresholds, content verification rules if needed. But above basics will validate web server availability.

Deploying the Cloudflare Load Balancer

We have now defined the core components viz. origins, origin groups and health checks. Click the orange cloud button to deploy your Cloudflare load balancer!

Within a few minutes, Cloudflare will propagate DNS settings across its vast network and also validate health checks. Your web servers on GCP and AWS are now load balanced and available globally!

Testing Cloudflare Load Balancing in Action

The true validation lies in testing user traffic routing. Access the Cloudflare domain in your browser a few times and observe results:

Refresh #1

Hello from GCP!

Refresh #2

Hello from AWS! 

We can confirm Cloudflare is successfully load balancing requests across the GCP and AWS backends in a round robin fashion!

You can dig deeper to analyze traffic distribution, connect times etc. using Cloudflare Load Balancing Analytics.

Now let‘s explore some bonus tips on advanced management.

Additional Cloudflare Load Balancing Capabilities

We‘ve only scratched the surface of the powerful traffic steering capabilities within Cloudflare. You can further optimize and customize your global load balancer using:

Custom Health Checks

Expand monitoring by modifying intervals, timeouts, validating response content, status codes beyond basics shown earlier. Add secondary failover origin pools that take over when primary pool health checks fail.

Geo-Fencing Rules

Refine traffic routing by user geography and proximity using rules to steer visitors to origins hosting region-specific content.

Load Shedding

Retry budgets, circuit breakers etc. to gracefully failover when origins become unavailable or overloaded.

Sticky Sessions

Ensure user stickiness to an origin for the duration of a session.

Low RTT Failover

Redirect visitors away from degraded origins with high latency.

Security and Performance

Enable additional DDoS, firewall rules, caching configurations depending on needs.

Dashboards and Analytics

Cloudflare integrates with Grafana, Splunk, Datadog for advanced monitoring and analytics.

API and Automation

Manage pools, origins, traffic policies programmatically via APIs for infrastructure automation.

These expanded capabilities all integrate seamlessly with core load distribution. Now let‘s conclude with some closing notes.

Conclusion and Key Takeaways

Migrating applications to the cloud often requires distribution across regions, data centers and platforms for high availability. Cloudflare solves this global load balancing complexity through its vast edge network spanning on-ramps in over 275 cities.

We walked through a hands-on demonstration for cross-cloud load balancing between GCP and AWS environments. With simple origin and health check configuration, Cloudflare efficiently routes traffic across web servers on both platforms improving failover and geographic coverage.

Apart from resilient, low latency multi-cloud load balancing, Cloudflare brings ancillary benefits around DDoS protection, CDN caching, managed firewall – packaged as an integrated cloud networking platform.

So in summary, here are the major benefits for utilizing Cloudflare‘s services:

  • Quickly load balance across hybrid or multi-cloud infrastructure
  • Route traffic intelligently based on location, utilization and availability zones
  • Single unified dashboard for simplified management
  • Improved scale, responsiveness and uptime versus cloud-specific solutions
  • Rich ecosystem for monitoring, automation and security analytics

I encourage you to sign up for a free Cloudflare account, optionally upgrading to $5/month basic load balancing plan to test across your cloud environments. Feel free to engage via comments in case of any questions on advanced setup or troubleshooting techniques!