Unable to perform vMotion due to missing TCP/IP gateway

Products

• VMware vSphere ESXi
• VMware vCenter Server

Issue/Introduction

• vMotion migrations fail in both directions when the destination host cannot receive data from the source host on the vMotion network. This issue often arises after configuring a new VMkernel adapter for vMotion on a different subnet.
• Error Message: "The vMotion failed because the destination host did not receive data from the source host on the vMotion network. Please check your vMotion network settings and physical network configuration and ensure they are correct."

• Additionally, ping tests between vMotion VMkernel interfaces may fail with "sendto() failed (Network is unreachable)" or 100% packet loss.

Environment

• VMware vCenter Server 8.0
• VMware vSphere ESXi 8.0

Cause

• The issue is caused by a missing gateway address in the vMotion TCP/IP stack configuration.
• When vMotion traffic must travel between different network segments or subnets, the dedicated vMotion TCP/IP stack requires a gateway address to route traffic correctly. If this address is missing, the traffic cannot be routed.
• An incorrect VLAN configuration at the port group level can contribute to connectivity failures.

Resolution

1. Verify Distributed Port Group VLAN Configuration
   
   1. Ensure the Distributed Port Group used for vMotion is configured with the correct VLAN ID.
   2. Confirm that the VLAN ID matches the configuration on the physical switch ports.
      
      
2. Configure the vMotion Gateway
   1. Log in to the vSphere Client.
   2. Navigate to ESXi Host > Configure > Networking > TCP/IP configuration.
   3. Select the vMotion TCP/IP stack and click Edit.
   4. In the IPv4 Gateway field, enter the correct gateway IP address for the vMotion network.
   5. Click OK to save the changes.
      
      
3. Validate Connectivity
   
   1. Use the nc (netcat) utility to verify connectivity on port 8000: nc -zv <Destination_IP> 8000
   2. From the ESXi CLI, verify host connectivity using the vMotion stack: vmkping -I vmk## -S vmotion <Destination_vMotion_IP>
   3. Successful responses confirm proper routing and connectivity.

Additional Information

While recreating the VMkernel adapter using the default TCP/IP stack may appear to resolve the issue because it inherits the default gateway, we recommend using the dedicated vMotion TCP/IP stack with its own correctly configured gateway to ensure optimal performance and isolation.

How to Place vSphere vMotion Traffic on the vMotion TCP/IP Stack of Your ESXi Host

For further assistance, Contact Broadcom Support.