Customized Ubuntu VM which uses Netplan could have multiple static IP addresses for a single network interface

Products

• VMware vSphere ESXi
• VMware vCenter Server

Issue/Introduction

Symptoms:
When a Ubuntu VM or template which uses Netplan as network configuration has a static IP address set for network interface, and this VM or template is customized to have a new static IP address for the same network interface, then the customized Ubuntu VM will have both static IP addresses set for the network interface, in particular the new static IP address will be the secondary IP.

Environment

VMware vSphere ESXi 6.7
VMware vSphere ESXi 6.5

Cause

The Netplan supports multiple IP address for a single network interface. The new IP address set by customization will be appended to existing IP address for the same network interface as the secondary IP address.

Resolution

Currently, there is no resolution.

Workaround:
To workaround this issue: 

Workaround 1:

Modify the existing Netplan configuration files /etc/netplan/01-netcfg.yaml and set network interface configuration to DHCP before VMware customization.

Workaround 2:

Delete the existing Netplan configuration files /etc/netplan/01-netcfg.yaml. The VMware customization will create a new Netplan configuration file which will be correctly configured.

Workaround 3:

Manual IP address reconfiguration.

Additional Information

On Ubuntu 20.04, guest customization populates /etc/network/interfaces and ignores that netplan is in use. The network customization has no effect.