You can provide high-availability to TKG clusters when they are deployed on a three vSphere Zone Supervisor. A vSphere Zone maps to a vSphere cluster, which means that when you deploy a Supervisor on three vSphere Zones, it utilizes the resources of all three underlying vSphere clusters. This protects your workloads running inside TKG clusters against failure on a vSphere cluster level. On a single-zone deployment, high-availability for TKG clusters is provided on an ESXi host level by vSphere HA.
In a three-zone Supervisor, control plane nodes of TKG clusters are automatically placed across the vSphere Zones. However, you control how TKG cluster worker nodes are spread across zones. You must define a NodePool object for the worker nodes of TKG clusters and map each vSphere Zone to a FailureDomain within each NodePool. This way, Cluster API takes care to spread the worker nodes across vSphere Zones accordingly. For more information about how to configure HA for TKG clusters, see v1apha3 Example: TKC Across vSphere Zones.
