Thanks to Cilium-powered cross-cluster networking, we now offer a fully managed, high-performance network solution that connects your entire cluster fleet seamlessly.
As businesses modernize their applications, the way cloud-native infrastructure is designed is changing fundamentally. The focus has shifted from “How do we scale a single cluster?” to “How do we scale across multiple clusters, regions, and clouds while keeping operations simple?”
Today, we’re excited to introduce the public preview of cross-cluster networking for Azure Kubernetes Fleet Manager. This new feature marks a major step forward in multi-cluster management, bringing transparent east-west multi-cluster networking powered by Advanced Container Networking Services.
The challenge of multi-cluster networking
Whether it’s due to compliance rules, disaster recovery needs, or the desire to limit the impact of failures, organizations of all sizes frequently run multiple Azure Kubernetes Service (AKS) clusters. Yet, managing these clusters has traditionally come with a “networking tax.” Conventional methods depend on complicated VPNs, gateways, and manual service discovery, which add delays and extra management work.
Even with just a handful of clusters—and especially when dealing with large fleets—teams need dependable cross-cluster connections for tasks like failover, shared service setups, and smoothly moving workloads between regions for capacity or performance. At the same time, platform teams aim to hide infrastructure complexity from developers, allowing changes at the cluster level without affecting applications.
Our vision: Multi-cluster management with seamless networking
To tackle these challenges, we created Azure Kubernetes Fleet Manager. Fleet Manager is built to make multi-cluster Kubernetes easier for everyone. While it has already streamlined workload distribution (deploying across many clusters) and update coordination (safe, phased upgrades), networking was still a hurdle.
With Cilium-based cross-cluster networking now part of Azure Kubernetes Fleet Manager, we’re providing a managed, high-performance network that spans your entire fleet.
This feature extends Kubernetes networking across clusters, letting services and workloads talk to each other across cluster borders as though they were on the same local network, while still keeping cluster-level separation and control.
Built on open-source technology, this solution uses Cilium for data handling and Kubefleet for fleet-wide coordination, both active Cloud Native Computing Foundation (CNCF) projects. This guarantees openness, flexibility, and compatibility with the wider Kubernetes community, while benefiting from ongoing improvements from the open-source world.
The diagram below illustrates how clusters within a fleet are linked through a single, managed network, enabling smooth communication, service discovery, and policy enforcement.
Key features include:
- Smooth east-west connectivity: Leveraging eBPF-based routing with Azure CNI powered by Cilium and Advanced Container Networking Services, pods can communicate across clusters at native speed—no proxies or gateways needed.
- Global service discovery: By adding a simple annotation (service.cilium.io/global=true), any standard Kubernetes Service becomes “global.” Cross-cluster networking automatically finds endpoints across connected member clusters, offering transparent load balancing and failover.
- Multi-cluster observability: Get a unified view of network health across all clusters with combined metrics, logs, and traffic visibility. Advanced Container Networking Services integrates Cilium telemetry to deliver consistent insights, quicker troubleshooting, and full visibility across the fleet.
- Unified security and governance: Security policies are no longer limited to individual clusters. With Advanced Container Networking Services, you can enforce enterprise-level network policies and gain deep observability across your global infrastructure, ensuring identity-based security follows your workloads wherever they run.
- Zero-touch management: Fleet Manager takes care of the complex lifecycle, handling certificates and network configurations, so you don’t have to.
These capabilities use eBPF to enable efficient routing, policy enforcement, and observability for high-performance networking.
Strategic resilience with cross-cluster networking
In a digital-first
In today’s digital economy, having a strong, resilient system is a real competitive edge. With networking across multiple clusters, customers can design setups that naturally withstand failures in a single cluster or region.
Whether you operate “Shared Services” clusters supporting many tenants or build “Global Services” that direct traffic to the healthiest available endpoints, cross-cluster networking for Azure Kubernetes Fleet Manager guarantees your infrastructure is as flexible as your business requires.
We are dedicated to offering the most powerful, secure, and high-performing platform for multi-cluster environments. Cross-cluster networking is a major milestone toward a future where a cluster’s physical limits no longer restrict the innovation happening inside it.
Getting started with cross-cluster networking
Cross-cluster networking for Azure Kubernetes Fleet Manager is built to reduce operational difficulty:
Prerequisites for your clusters:
- Azure CNI powered by Cilium used as the networking dataplane.
- Advanced Container Networking Services turned on.
Set up cross-cluster networking:
- Join clusters to a Fleet.
- Link the members with a cross-cluster network profile.
- Deploy services with global annotations to enable cross-cluster communication.
Once set up, Fleet Manager automatically deploys and handles the necessary parts, allowing direct pod-to-pod communication across clusters without extra gateways or overlays.
This managed method takes away the trouble of setting up and maintaining Cilium multi-cluster components by hand, letting teams focus on delivering applications instead of handling infrastructure.
See it in action: Watch the Cross-Cluster Networking for Azure Kubernetes Fleet Manager Video Guide to learn more and see a quick demo.
Documentation and resources
If you have feedback or want to learn more, reach out to your Microsoft account team or share feedback through the Azure Kubernetes Service community channels, we would love to hear from you!
