Google Cloud Platform

Announcing IPv6 global load balancing GA

Google Cloud users deploy Cloud Load Balancing to instantiate applications across the globe, architect for the highest levels of availability, and deliver applications with low latency. Today, we’re excited to announce that IPv6 global load balancing is now generally available (GA).

Until today, global load balancing was available only for IPv4 clients. With this launch, your IPv6 clients can connect to an IPv6 load balancing VIP (Virtual IP) and get load balanced to IPv4 application instances using HTTP(S) Load Balancing, SSL proxy, and TCP proxy. You now get the same management simplicity of using a single anycast IPv6 VIP for application instances in multiple regions.

Home Depot serves 75% of homedepot.com out of Google Cloud Platform (GCP) and uses global load balancing to achieve a global footprint and resiliency for its service with low management overhead.

On the front-end, we use the Layer 7 load balancer with a single global IP that intelligently routes customer requests to the closest location. Global load balancing will allow us to easily add another region in the future without any DNS record changes, or for that matter, doing anything besides adding VMs in the right location. — Ravi Yeddula, Senior Director Platform Architecture and Application Development, The Home Depot

IPv6 support unlocks new capabilities 

With IPv6 global load balancing, you can build more scalable and resilient applications on GCP, with the following benefits:
  • Single Anycast IPv6 VIP for multi-region deployment: Now, you only need one Load Balancer IPv6 VIP for application instances running across multiple regions. This means that your DNS server has a single AAAA record and that you don’t need to load-balance among multiple IPv6 VIPs. Caching of AAAA records by clients is not an issue since there's only one IPv6 VIP to cache. User requests to IPv6 VIP are automatically load balanced to the closest healthy instance with available capacity.

  • Support for a variety of traffic types: You can load balance HTTP, HTTPS, HTTP/2, TCP and TLS (non-HTTP) IPv6 client traffic. 
  • Cross-region overflow with a single IPv6 Load Balancer VIP: If instances in one region are out of resources, the IPv6 global load balancer automatically directs requests from users closest to this region to another region with available resources. Once the closest region has available resources, global load balancing reverts back to serving user requests via instances in this region. 
  • Cross-region failover with single IPv6 Load Balancer VIP: If the region with instances closest to the user experiences a failure, IPv6 global load balancing automatically directs traffic to another region with healthy instances. 
  • Dual-stack applications: To serve both IPv6 and IPv4 clients, create two load balancer IPs — one with an IPv6 VIP and the other with an IPv4 VIP — and associate both VIPs with the same IPv4 application instances. IPv4 clients connect to the IPv4 Load Balancer VIP while IPv6 clients connect to IPv6 Load Balancer VIP. These clients are then automatically load balanced to the closest healthy instance with available capacity. We provide IPv6 VIPs (forwarding rules) without charge, so you pay for only the IPv4 ones.

A global, scalable, resilient foundation 


Global load balancing for both IPv6 and IPv4 clients benefits from its scalable, software-defined architecture that reduces latency for end users and ensures a great user experience.


  • Software-defined, globally distributed load balancing: Global load balancing is delivered via software-defined, globally distributed systems. This means that you won’t hit performance bottlenecks with the load balancer and it can handle 1,000,000+ queries per second seamlessly. 
  • Reduced latency through edge-based architecture: Global load balancing is delivered at the edge of Google's global network from 80+ points of presence (POPs) across the globe. User connections terminate at the POP closest to them and travel over Google's global network to the load-balanced instance in Google Cloud. 

  • Seamless autoscaling: Global load balancing scales application instances up or down automatically based on traffic — no pre-warming of instances required. 

Take IPv6 global load balancing for a spin 

Earlier this year, we gave a sneak preview of IPv6 global load balancing at Google Cloud Next ‘17. You can test drive this feature using the same setup.

In this setup:


  • v6.gcpnetworking.com is served by IPv4 application instances in multiple Google Cloud regions across the globe. 
  • A single anycast IPv6 Load Balancer IP, 2600:1901:0:ab8:: fronts the IPv4 application instances across regions 
  • When you connect using an IPv6 address to this website, IPv6 global load balancing directs you to a healthy Google Cloud instance that's closest to you and has available capacity. 
  • The website is programmed to display your IPv6 address, the Load Balancer IPv6 VIP and information about the instance serving your request. 
  • v6.gcpnetworking.com will only work with IPv6 clients. You can test drive gcpnetworking.com instead if you want to test with both IPv4 and IPv6 clients.
For example, when I connect to v6.gcpnetworking.com from California, my request connects to an IPv6 global load balancer with IP address 2600:1901:0:ab8:: and is served out of an instance in us-west1-c, the closest region to California in the set-up.

Give it a try, and you'll observe that while your request connects to the same IPv6 VIP address 2600:1901:0:ab8::, it's served by an instance closest to you that has available capacity.

You can learn more by reading about IPv6 global load balancing, and taking it for a spin. We look forward to your feedback