This article is contunuation of the previouse one: VCF Fleet with Site High Availability (Across Zones)

Now let’s move from high availability within a region to disaster recovery across regions.

On this slide we have:

• Region 1, which acts as the primary site, and

• Region 2, which acts as the disaster recovery site.

This article is contunuation of the previouse one: VCF Fleet Basic

Once you’ve deployed that basic VCF instance with Ops and Automation, you can scale out to multiple VCF instances.

On the icture below you can see several VCF instances, each with:

• Its own workload domain components – vCenter, NSX, and storage.

• Its own management domain where required.

This is first of 5 Fleet design patterns.

This is core concept of a VCF Fleet Basic deployment.

Think of this as our baseline VCF instance design – the foundation for all the other VCF Fleet deployment options I’ll cover next.

VMware has released a new video demonstrating the end-to-end upgrade journey from an existing vSphere 8.x environment with Aria Suite to the latest VMware Cloud Foundation (VCF) 9.0 platform.

LINK TO VIDEO

The walkthrough showcases an environment that initially relies on Aria Suite Lifecycle Manager and Aria Operations, and illustrates how it is transitioned to the new VCF 9 operating model.
The process begins with upgrading Aria Lifecycle Manager to version 8.18 Patch 2 or later, which is a mandatory prerequisite. Using this updated lifecycle manager, Aria Operations is then upgraded to VCF Operations 9.0, during which a new component—the VCF 9 Fleet Management Appliance—is automatically deployed.

Standardizing Terminology Across Cloud and VCF

The key idea is to avoid inventing proprietary terminology and instead rely on concepts that are already widely understood across the cloud industry. Terms such as Region and Availability Zone are common reference points across AWS, Google Cloud, Azure, and other platforms—and they translate well into VMware Cloud Foundation (VCF) architectures.

By using familiar terminology, we make architecture discussions clearer, more portable, and easier to align with existing cloud operating models.

The VMware Cloud Foundation Architecture poster has been comprehensively refreshed to reflect the major innovations introduced with VCF 9, marking a significant evolution of the platform. It delivers a powerful visual narrative that brings the full software-defined data center and cloud operating model to life.

Download full version

More than a diagram, the poster acts as a strategic blueprint for understanding how VCF enables and operates modern private cloud environments. It clearly demonstrates how the platform supports traditional virtual machines alongside cloud-native and next-generation workloads, including Kubernetes, AI, and big data, across multiple data centers and edge locations.

At its core, the poster showcases how compute, storage, networking, and security are tightly integrated into a single, automated, and lifecycle-managed stack. It illustrates how VCF is deployed, scaled, and operated as a true end-to-end private cloud platform, delivering cloud-like agility with enterprise-grade control.

Modern enterprise workloads demand high availability, resilience, and automated recovery across geographically separated locations. VMware Cloud Foundation (VCF) addresses these requirements through Multi Availability Zone (AZ) deployments using vSphere and vSAN stretched clusters. This architecture enables continuous service availability even during an entire Availability Zone outage, while maintaining centralized management and operational simplicity.

What Is a Stretched Cluster in VCF?

A vSphere stretched cluster is a single vSphere cluster with vSAN storage that spans multiple Availability Zones (AZs). Each AZ is treated as an independent Failure Domain, typically representing a separate data center, building, or fault-isolated zone with independent power, cooling, and network paths.

In a stretched cluster architecture:

• Compute hosts are distributed across two AZs.

• vSAN synchronously replicates data between AZs.

• A vSAN witness node provides quorum to prevent split-brain scenarios.

This design allows workloads to remain available and consistent even if one AZ becomes unavailable.

Key Architectural Components

1. Availability Zones as Failure Domains

Each Availability Zone acts as a vSAN Fault Domain, ensuring that data replicas are placed across AZs. This guarantees that the loss of an entire AZ does not impact data availability or integrity.

2. vSAN Stretched Storage

vSAN uses synchronous replication between AZs to maintain identical data copies. This ensures:

• Zero data loss (RPO = 0)

• Transparent storage access for virtual machines

• Consistent performance under normal operating conditions

3. vSAN Witness Node

A vSAN witness node is mandatory for stretched clusters. It:

• Maintains quorum during failures

• Resides in a third fault location (separate from both AZs)

• Stores only metadata, not workload data

The witness ensures deterministic behavior during AZ failures and enables automated recovery.

High Availability and Automated Recovery

One of the major benefits of stretched clusters in VCF is the retention of native vSphere features:

• vSphere HA automatically restarts affected virtual machines in the surviving AZ in the event of an AZ failure.

• DRS (Distributed Resource Scheduler) continues to balance workloads dynamically based on available compute resources.

• No manual intervention is required for workload recovery, significantly reducing operational risk and recovery time.

This results in a fully automated and highly resilient platform capable of surviving complete AZ outages.

Deployment Order and Best Practices in VCF

Management Domain First

In VCF, the Management Domain cluster must be stretched first before stretching any VI Workload Domain (WLD) vSAN clusters. This is critical because:

• The Management Domain hosts core infrastructure services such as SDDC Manager, vCenter, NSX, and lifecycle management components.

• Ensuring its availability is foundational for the entire VCF stack.

Stretch VI Workload Domains as Needed

After the Management Domain is successfully stretched:

• Additional vSAN-based VI Workload Domain clusters can be stretched selectively.

• Not all clusters need to be stretched—only those hosting workloads with strict availability and resiliency requirements.

• This approach allows organizations to balance cost, complexity, and availability.

Use Cases and Benefits

Multi-AZ stretched clusters in VCF are ideal for:

• Mission-critical applications requiring continuous availability

• Environments with zero or near-zero downtime requirements

• Enterprises seeking simplified disaster avoidance rather than traditional disaster recovery

Key benefits include:

• Protection against entire AZ failures

• Zero data loss and rapid recovery

• Fully automated operations using native vSphere capabilities

• Consistent management through VMware Cloud Foundation

Conclusion

VCF Multi Availability Zone deployments using stretched clusters provide a powerful, resilient architecture for modern private cloud environments. By leveraging vSphere HA, DRS, and vSAN stretched storage—with the correct deployment order starting from the Management Domain—organizations can achieve enterprise-grade availability with minimal operational overhead.

This architecture transforms Availability Zones into active-active infrastructure components, ensuring business continuity even in the face of major infrastructure failures.