vCenter Server Connectivity Lost to ESXi Hosts and SSH After Adding a New NIC in VAMI

Products

• VMware vCenter Server

Issue/Introduction

• After adding a new network interface (e.g., eth4) in the vCenter Server Appliance Management Interface (VAMI).
• A reboot of the vCenter Server Appliance (VCSA) is performed.
• Connectivity to ESXi hosts via secondary management interfaces (e.g., eth2) is lost.
• SSH access to the vCenter Server (typically on eth0) becomes unavailable.
• The vCenter Web Client and VAMI remain accessible on the primary management interface.

Environment

VMware vSphere ESXi
VMware vCenter Server

Cause

Adding a new network interface without explicitly configuring a default gateway or verifying the global routing table in VAMI can lead to a missing default gateway or routing conflicts upon reboot. The VCSA may fail to populate the correct default route if the network configuration is incomplete or if the appliance becomes ambiguous about which interface should hold the default route.

Resolution

To restore connectivity and SSH access, the default gateway must be manually re-applied or verified through the appliance shell using the VAMI configuration tool.

1. Access the Appliance Console:
   Log in to the VCSA via the Direct Console User Interface (DCUI) or a remote console session (e.g., through the ESXi host UI where the vCenter VM resides).
2. Launch the Network Configuration Tool:
   From the appliance command line, enter the following command:
   bash
/opt/vmware/share/vami/vami_config_net
3. Re-configure Management Network:
   Select the menu options to configure the existing management interfaces (typically eth0 or eth2).
4. Verify and Apply Default Gateway:
   Ensure that the correct IP address is present and that the Default Gateway is explicitly set. Save the configuration within the tool.
5. Verify the Routing Table:
   Exit the tool to the shell and verify the active routing table:
   bash
ip route
   Ensure the default route points to the correct gateway IP and the intended management interface.
6. Optional: Restart Management Services:
   If connectivity to ESXi hosts is not immediately restored, restart the vCenter services:
   bash
service-control --stop --all
service-control --start --all

Additional Information

vCenter network connectivity lost - Recover vCenter network when connected to a Distributed Switch