Within the workload domain architecture (WLD), the domain starts with a single VxRail cluster. The cluster can have a minimum of three VxRail hosts in each VxRail cluster, and it scale up to maximum configurations supported by vSphere or VSAN. Multiple clusters can be created per domain. Each domain has its own vCenter server instance and is patched and upgraded independently. The vCenter Server instance for all the workload domains is configured with enhanced linked mode. This mode allows for a central visibility and control while also allowing role-based access controls to be used to secure and limit access. Multicluster domains enable scalability.
From the VxRail clusters, you can organize separate pools of capacity into WLDs, each with its own set of specified CPU, memory, and storage requirements. These WLDs can support various workloads types such as VMware Horizon or business-critical apps like databases.
Two types of WLDs can be deployed:
The management workload domain (Mgmt WLD) cluster requires a minimum of four hosts that run the infrastructure components used to instantiate and manage the private cloud infrastructure. For VCF on VxRail, the management WLD should not be used to host business workloads. This management WLD is created during initial system installation (or bring-up) using the VCF Cloud Builder tool.
In the Management WLD cluster, vSphere runs with a dedicated vCenter server that is backed by vSAN storage. It hosts SDDC Manager and VxRail Manager VMs, NSX-V, and vRealize Log Insight for management domain logging. Other components such as vRealize Operations and vRealize Automation are optional. If a Horizon WLD is deployed, the management components are also deployed in the Mgmt WLD. The management cluster must have a minimum of four hosts to provide vSAN FTT=1 during maintenance operations. While the deployment and configuration of the management cluster is fully automated when it is running, it can be managed like the other VxRail cluster by using the vSphere HTML5 client.
The management domain vCenter Server is deployed using the standard VxRail cluster deployment process that uses internal VCSA deployment. This vCenter Server is configured as an external vCenter using the vCenter server UI.
This conversion is performed for two reasons:
The virtual infrastructure workload domain (VI WLD) can consist of one or more VxRail clusters. The VxRail cluster is the building block for the VxRail VI WLD. The first cluster of each VI WLD must have four hosts, but subsequent clusters can start with three hosts. The VI WLD can be either an NSX-V based WLD or an NSX-T based WLD. This can be selected when adding the first cluster to the WLD. The vCenter and NSX-V or NSX-T Manager for each VI WLD are deployed into the Mgmt WLD. For an NSX-V based VI WLD, the controllers are deployed to the first cluster in the VI WLD that is added by the SDDC Manager. Each new VI WLD requires an NSX-V Manager to be deployed in the Mgmt WLD and the three controllers deployed into the first cluster of the VI WLD.
For an NSX-T based VI WLD, when the first cluster is added to the first VI WLD, the NSX-T Managers (three per cluster) are deployed to the Mgmt WLD. Subsequent NSX-T based VI WLDs do not require additional NSX-T mangers, but each VI WLD VI is added as a compute manager to NSX-T.
For both NSX-T based VI WLDs and NSV-V based VI WLDs, the first cluster can be considered a compute-and edge cluster since it contains both NSX and compute components. NSX virtual routers can be deployed to this first cluster. The second and subsequent clusters in a VI WLD can be considered compute-only clusters since they do not host any NSX routing virtual machines.
The VI WLD vCenter server is deployed by the SDDC Manager when creating a VI WLD. It is deployed in the Mgmt WLD. During deployment, it is added to the existing SSO domain, allowing a single pane of glass to manage both the management and VI WLD vCenter servers.