The management domain is a cluster of physical hosts that contain the management component VMs.
VMware vSphere runs a dedicated VMware vCenter server in the management domain with VMware vSAN storage. The management domain hosts VMware SDDC Manager, VMware NSX Managers, and VMware vSphere vCenter. If virtual network segments are used, two VMware NSX edge node VMs connect the VMware NSX virtual network and the physical network components.
Before you deploy the management domain, size AMP Central with the following considerations:
VCF requires four or more medium or large AMP Central servers to deploy VCF. VMware Cloud Builder deploys the management domain onto AMP Central with VMware vSAN in an integrated or stand-alone configuration.
A region is a single instance of VCF that contains a separate VMware SDDC instance for VCF high availability. An availability zone (AZ) in the management domain is a collection of infrastructure components. Each availability zone is isolated to prevent failure propagation or an outage that spans a data center. Each availability zone runs on a discrete physical independent highly reliable infrastructure. Each availability zone should be physically separated, so that disasters affect only one availability zone. The availability zones can exist in a metro distance or two safety or fire zones in the same data center.
The VCF management domain cluster can be stretched across two availability zones within a region. Both availability zones must have an equal number of symmetrical hosts to ensure failover in case an availability zone goes down.
The following figure depicts a VxBlock System 1000 with multiple availability zones in a region:
Stretch the VCF Management domain cluster before stretching the VI workload domains. Stretching the VCF management domain cluster ensures the following:
The VCF management domain stretched cluster supports VMs based on their availability requirements. Each availability zone has a VxBlock 1000. Each VxBlock 1000 has a dedicated set of VMs for out-of-band management. Examples of these VMs include the Windows 2019 Element Manager for out-of-band management and Dell Secure Remote Services appliances. The dedicated out-of-band management VMs do not fail over between availability zones. The dedicated VMs may also be identified in documentation as non-stretch VMs. VMs that can failover between availability zones have both local and site protection. VMs that cannot fail over between availability zones have only local protection. The level of protection for a VM depends on the vSAN storage policies and cluster-level affinity rules.
Use cases for a stretch cluster include:
The management domain vSAN stretched cluster requires a witness host that is deployed in a vSAN witness zone, which must be different from AZ1 and AZ2. The vSAN witness host is deployed using an appliance, does not run any VMs, and must run the same version of ESXi as the ESXi management host. The witness host must be deployed in a separate VCF instance or in a non-VCF-based VMware vCenter server. The witness appliance has the following features:
This appliance is deployed in a medium appliance size.