I was recently involved in a NSX deployment where the ESX hosts (VTEPs) were not able to communicate with each other. The NSX manager UI showed that few ESX hosts in the cluster were not prepared even though the entire cluster was prepared. We quickly took a look at the ESX hosts and found that the VXLAN vmk interfaces were missing but the VIBs were still installed. Re-preparing these hosts failed with no IP addresses available in the VTEP IP pool.
To cut a long story short, We had to remove some IP addresses from the IP pool and apparently there is no way to do this from the NSX UI without deleting and re-creating the IP pool. Even with deleting and re-creating the IP pool, you can only provide a single set of contiguous IP addresses. Fortunately there is a Rest API method available to accomplish this.
So to remove an IP address from the pool we first need to find the pool-id. Using a Rest client run this GET request to get the pool-id
The output would list all the configured IP pools. We need to look at the objectId tag to get the pool-id. Once we have the pool-id we can query the pool to verify the start and end of the IP pool
To remove an IP address from this pool use the Delete method along with IP address like so,
Note: With this method you can only remove IP addresses that have been allocated and not free addresses in the pool.