IP Pools
Two different "IP pools" — don't mix them up
Nutanix reuses the term "IP pool" for two unrelated things. Both come up when you're doing backplane/segmentation work, but they address completely different traffic.
| Segmentation IP pool | AHV VM network IPAM pool | |
|---|---|---|
| Addresses | CVM (and host) backplane/service vNICs | User VMs on an AHV-managed network |
| Configured in | Settings → Network Configuration → Internal Interfaces (or Prism Central Network Segmentation) | Prism → Network Config → the VM subnet, or acli |
| Routable? | No for Backplane, yes for Service/DR | Depends on the VM network's own VLAN |
| Assignment | Automatic, one IP per CVM/host, no DHCP involved | Nutanix-managed DHCP hands addresses to VMs on boot |
Segmentation IP pool (Backplane / Service)
When you enable Backplane or Service segmentation, Prism asks for a start/end range, e.g.:
192.168.21.11 - 192.168.21.20Size it for the cluster's current node count plus headroom for future expansion — one address is consumed per CVM (and, on current AOS, per AHV host) for each segmented traffic type. There's no reuse or lease/DHCP mechanism here: once an address is assigned it stays assigned until the interface is reconfigured.
AHV VM network IPAM pool
Separate from the above — this is Nutanix-managed DHCP for guest VMs on a given AHV network, already referenced on Important Commands in this book:
acli net.create <name> vlan=<vlan_id> ip_config=<subnet/prefix>The command above only creates the network/subnet — the actual address pool for it is added separately:
acli net.add_dhcp_pool <name> start=<first_ip> end=<last_ip>or in Prism: the VM network's config page → "IP Address Pools" → Create Pool.
Gotcha: .254 in the subnet is reserved for the Acropolis DHCP server itself if you didn't explicitly set a DHCP server address when creating the network — don't include it in the pool range.
This pool has nothing to do with the CVM/host backplane above — it only ever hands out addresses to VMs that sit on this particular AHV network.