Azure Kubernetes Fleet Manager gets cross-cluster networking

Introduction

Running applications across multiple AKS clusters is increasingly common for regional resiliency, disaster recovery, compliance, and workload isolation. But networking between clusters has often required extra gateways, VPNs, and manual service discovery, adding operational overhead. Microsoft is now addressing that challenge with public preview cross-cluster networking for Azure Kubernetes Fleet Manager.

What's new

This new capability extends Kubernetes networking across clusters in a fleet so workloads can communicate more naturally across boundaries.

Key capabilities

• Seamless east-west connectivity across AKS clusters using Azure CNI powered by Cilium and Advanced Container Networking Services
• No extra proxies or gateways required for pod-to-pod communication across clusters
• Global service discovery using a simple Kubernetes service annotation: service.cilium.io/global=true
• Transparent load balancing and failover across joined fleet member clusters
• Multi-cluster observability with aggregated metrics, logs, and flow visibility
• Unified security and governance with network policies and observability that span cluster boundaries
• Zero-touch lifecycle management for certificates and network configuration through Fleet Manager

Microsoft says the feature is built on open-source technologies including Cilium for the dataplane and Kubefleet for fleet orchestration, which should appeal to organizations looking for portability and ecosystem alignment.

Why this matters for IT teams

For Azure administrators and platform engineers, this preview reduces the "networking tax" of multi-cluster AKS deployments. Instead of stitching clusters together manually, teams can use a managed approach to support:

• Regional failover and disaster recovery
• Shared services across multiple clusters
• Global application architectures
• Easier workload mobility across regions
• Better visibility into network health and policy enforcement

This is especially valuable for enterprises operating large AKS fleets where consistency, governance, and resilience are critical.

Requirements and next steps

To use cross-cluster networking, organizations need:

• Azure CNI powered by Cilium as the networking dataplane
• Advanced Container Networking Services enabled
• AKS clusters joined to an Azure Kubernetes Fleet Manager fleet
• A configured cross-cluster network profile

After setup, administrators can deploy services with the global annotation to enable cross-cluster communication.

What to do now

If you manage multi-region or multi-cluster AKS environments, this preview is worth evaluating in a test environment. Review the Fleet Manager documentation, validate prerequisites, and identify workloads that would benefit from simplified service discovery, failover, and centralized network policy management.