vSAN host shows network partitioned

Products

• VMware vSAN

Issue/Introduction

• vSAN host shows as network partition from the rest of the vSAN cluster
• VMs are down and showing as inaccessible in vCenter
• vSAN traffic using a LAG
• vmkping tests to/from all hosts in the cluster are successful
• Unicast agent list/table is intact/built for all hosts

Environment

VMware vSAN (All Versions)

Cause

The active vmnic within the LAG being used for vSAN traffic is not receiving traffic from the upstream switch

Resolution

1. Engage your networking team for further assistance
2. Connect to the impacted host via SSH
3. Run esxcli vsan network list to get the vmk in use by vSAN
4. Run esxtop > type n to get to networking
5. See which vmnic is actively being used by the vSAN vmk
6. Select the impacted host in vCenter > Configure > Networking > Virtual switches
7. Select the Virtual switch being used for vSAN traffic
8. Expand the Uplinks and look for the vmnic you got from step 5
9. Click on the 3 ellipses (...)  > View Settings and look at the CDP info to see which switch and port the host is connected to
   Note: This info is not always populated so you may have to provide the MAC address for the vmnic to your networking team. The MAC address can be found from host > Configure > Networking > Physical adapters
10. Have your networking team confirm the switch & port the host is connected to from the switch side and have them check the logs for any issues
11. Try bouncing the vmnic from the ESXi host by running esxcli network nic down -n vmnic followed by esxcli network nic up -n vmnic