VM Creation Fails with No AvaiIable IP

Problem

Unable to create a VM on a subnet because the UI reports no available IPs, even though the allocation pool still has free addresses.

Environment

• Private Cloud Director Virtualization - till v2026.1-360

• Private Cloud Director Kubernetes – till v2026.1-360

• Self-Hosted Private Cloud Director Virtualization - till v2026.1-360

• Self-Hosted Private Cloud Director Kubernetes - till v2026.1-360

• Component: Networking Service

Cause

The issue is caused by incorrect IP availability calculation. The system subtracts all used addresses in the subnet (including those outside the allocation pool) instead of only considering addresses within the defined allocation pool. This is a known bug tracked PCD-3647 and fix is available from v2026.1-360 and above

Diagnostics

1. Check subnet details and allocation pool configuration. Look for allocation_pools field and confirm the defined IP range.

   openstack subnet list --long 
   openstack subnet show <SUBNET_ID>

2. List all ports and IPs allocated in the subnet.Compare allocated IPs with allocation pool; verify how many pool IPs are actually in use.

   openstack port list --fixed-ip subnet=<SUBNET_ID> -c ID -c Fixed_IPs -c Device_ID

3. Verify mismatch in UI:

   1. In the UI → Network & Security → Physical/Virtual Networks→ Subnets, check the Available IPs field.

   2. Compare UI’s reported value (e.g., 0 or negative) against the manual calculation.

Workaround

Since the UI incorrectly reports available IPs, create VMs directly from the CLI using a free IP from the allocation pool.

openstack server create \
  --flavor <FLAVOR_ID> \
  --image <IMAGE_ID> \
  --nic net-id=<NETWORK_ID>,v4-fixed-ip=<FREE_IP> \
  --security-group <SECURITY_GROUP_ID> \
  --key-name <KEYNAME> \
   --availability-zone <CLUSTER_NAME> \
  <VM_NAME>