To clarify the versioning requirements between vCenter and ESXi
Symptoms:
Discrepancies in reporting between ESXi and vCenter
Slow updates from the Hosts to vCenter.
Environment
VMware vSAN 5.5.x VMware vCenter Server Appliance 6.0.x VMware vSAN 6.2.x VMware vCenter Server 6.5.x VMware vSAN 6.6.x VMware vCenter Server Appliance 5.0.x VMware vCenter Server 6.0.x VMware vSAN 6.0.x VMware vCenter Server Appliance 5.1.x VMware vCenter Server 7.0.x VMware vSphere ESXi 5.5 VMware vCenter Server Appliance 6.7.x VMware vCenter Server 5.0.x VMware vSAN 6.7.x VMware vCenter Server Appliance 5.5.x VMware vSAN 7.0.x VMware vSphere ESXi 5.0 VMware vSAN 6.5.x VMware vCenter Server Appliance 6.5.x VMware vCenter Server 6.7.x VMware vSphere ESXi 6.5 VMware vCenter Server 5.1.x VMware vCenter Server 5.5.x VMware vSAN 6.1.x VMware vSphere ESXi 6.0 VMware vSphere ESXi 6.7 VMware vCenter Server Appliance 5.0 VMware vSphere ESXi 5.1 VMware vSphere ESXi 7.0.0
Cause
Communication between ESXi and vCenter is critical for VMware environments and build compatibility is key to reliable functionality. Code updates resolve known issues and enhance communication between related products.
For more detailed information regarding best practices for upgrading the environment see the following KBs:
vSAN The health check feature of vSAN relies heavily on vCenter & ESXi communication and requires that vCenter be equal to or newer than the ESXi hosts for reliable communication.
vXRail As VXRail is built upon vSAN, it carries similar requirements for vCenter.
Note: Please verify that all the products are compatible with the version of vCenter when planning updates by using the Interoperability guide
Additional Information
Impact/Risks: In rare cases, ESXi hosts on a newer version than vCenter may not properly process the unicast agent updates. This can result in a vSAN network partition.