neutron_ovn_db_sync_util yields an IpAddressGenerationFailure for subnets without allocation pools

[Garrett Neugent]

While using the neutron_ovn_db_sync_util tool to repair an OVN database, I encountered an error for what seems to be an unhandled edge case.

Here was the command I used:

$ neutron-ovn-db-sync-util --config-file /path/to/neutron.conf --config-file /path/to/ml2_conf --ovn-neutron_sync_mode repair

The full output is here: https://pastebin.ubuntu.com/p/g6p7NTy2sK/

The relevant error snippet is:

"neutron_lib.exceptions.IpAddressGenerationFailure: No more IP addresses available on network"

The workaround in this case was:

1) identifying that two subnets on this network did not have allocation pools:

$ openstack subnet list --long -c ID -c Name -c Network -c Subnet -c "Allocation Pools"

2) Adding allocation pools with one IP address each:

openstack subnet set --allocation-pool start=xx.xx.xx.xx,end=xx.xx.xx.xx $subnet_id_1
openstack subnet set --allocation-pool start=yy.yy.yy.yy,end=yy.yy.yy.yy $subnet_id_2

3) re-running the repair command.