"% An error occurred while processing the interface command, reason: IP configuration already exists on another interface 'eth0'.", when attempting to configure mgmt IP for an Baremetal/Edge node

Products

• VMware NSX

Issue/Introduction

• You are configuring the management IP address for a different vNIC (eth1) on the edge node. This is because the previous management vNIC (eth0) was removed from vCenter, and you are now attempting to configure the eth1 interface.
• set interface <interface> ip <address> mask <netmask> plane mgmt
• You observe the following error: "% An error occurred while processing the interface command, reason: IP configuration already exists on another interface 'eth0'." However, you do not find 'eth0' displayed in 'get interfaces'.
• 

Environment

VMware NSX

Cause

• Although the eth0 vNIC was removed from the edge VM in vCenter and subsequently does not appear in the get interfaces output, its configuration (including the management IP address) still exists in the /etc/network/interfaces file in the root directory.
• The /etc/network/interfaces file is not automatically modified when the corresponding network adapter for eth0 is removed.

Resolution

• As a root user, you must modify the /etc/network/interfaces file to replace eth0 with eth1 (or the new management vNIC interface you are using). Then, restart the systemctl networking service (sudo systemctl service networking) for the interface change to take effect.
• You can verify that eth1 is configured with the management IP address by executing 'ip link' or 'ifconfig -a' after the systemctl restart