Duplicate IP addresses assigned to VMs on a network using a Network Protocol Profile

Products

• VMware vCenter Server

Issue/Introduction

Newly deployed virtual machines using a Network Protocol Profiles are getting assigned IP addresses that have already been allocated to previously deployed virtual machines.

Environment

VMware vCenter Server

Cause

• The original network name that includes the Network Protocol Profile was called 'Network1.'
• After the Network Protocol Profile was applied to various VMs using the vApp settings, this network's name was changed to 'Network2.'
• This name change created stale entries in the vCenter Server database such that when vCenter is restarted, it is unable to match allocated IP addresses on 'Network2' to IP addresses that were previously deployed on  'Network1.' 
• This failure to reserve the IP addresses on 'Network1' results in IPs being marked as free for use. 
• New allocations to 'Network2' run the risk of getting IP addresses that have already been allocated and are in use on VMs which still have the original stale 'Network1' network assigned with the Network Protocol Profile in their vApp configurations.

Resolution

To avoid this situation, do not rename networks after applying a Network Protocol Profile and deploying VMs to it.

To resolve this issue if the above has been done:

Workaround options

Delete the virtual machines deployed before the network name change:

1. Delete the older virtual machines.
2. After deleting the VMs, do NOT rename the port group associated with a Network Protocol Profile.

If deleting those VMs is not acceptable:

1. Rename the network Network2 to Network1.
2. Delete the existing Network Protocol Profile and create a new Network Protocol Profile associating with network Network1.
3. Restart vCenter Server.
   1. Since the older VMs and newer VMs and Network Protocol Profile will all have Network1, the reservation of the IPs in the pool will work correctly.

If renaming Network2 is also not acceptable:

1. Delete the current Network Protocol Profile.
2. Create a new one associating with Network2, but have a IP pool which is different from the IP pool previously used for Network1.
   1. This way, the new VMs will get IPs from a different pool range than the older VMs.