When you upgrade an ESXi host in a vSAN cluster of version earlier than vSAN 6.2 to ESXi 7.x, the vSAN network configuration might be lost

Products

• VMware vSAN

Issue/Introduction

To fix the vSAN network configuration.

Symptoms:

• Cluster started out on version prior to vSAN 6.2 (ESXi 6.0U2) or earlier
• The cluster was upgraded to 6.5 and/or 6.7 then to 7.x or directly to 7.x
• Hosts become partitioned
• vSAN Tag is missing from the respected vSAN vmk port

Environment

VMware vSAN 7.0.x
VMware vSAN 8.0.x

Cause

Entries for GroupV6 are missing from /etc/vmware/esx.conf, as these entries are missing from esx.conf VsanUpgradeConfig can't populate the configstore with the expected vSAN Network configuration.

Resolution

Prior to upgrading your 6.x cluster run the following command grep GroupV6 /etc/vmware/esx.conf to see if you're susceptible to this issue. If you get no results then upgrade vCenter/ESXi to either 7.0U3l or 8.0b or higher

If you see the below similar output then you're not susceptible of hitting this issue and can upgrade to any version of 7.x or 8.x, however, VMware recommends updating to the latest code of either 7.x or 8.x.

/vsan/network/child[0000]/agentGroupV6 = "ff19::x:x:4"
/vsan/network/child[0000]/masterGroupV6 = "ff19::x:x:3"

Workaround:
If the cluster has already been upgraded to 7.x below 7.0U3l or 8.x below 8.0b and experiencing host(s) partitioned from the cluster then check the vSAN vmk port and ensure the vSAN Tag is still present, if it's missing add it back and the host will join the cluster.

Additional Information

Impact/Risks:
Hosts become partitioned