L3Policy can be created with a subnet-prefix-length greater than that of ip-pool subnet.
If this L3Policy is now referred inside a L2Policy which in turn used to create a PTG, then PTG creation will fail due failure in creating a subnet
"NoSubnetAvailable: No subnet is available from l3 policy's pool."
Find the sequence of steps:
=========================
test@localhost:~/devstack$ gbp l3policy-create b --ip-pool 1.1.1.0/24 --subnet-prefix-length 16
Created a new l3_policy:
+----------------------+--------------------------------------+
| Field | Value |
+----------------------+--------------------------------------+
| description | |
| external_segments | {} |
| id | f4c7258d-76cb-4e5e-bfc8-41f49de56120 |
| ip_pool | 1.1.1.0/24 |
| ip_version | 4 |
| l2_policies | |
| name | b |
| routers | 0d234a6a-9713-4123-8b46-ea4acb9d8213 |
| shared | False |
| subnet_prefix_length | 16 |
| tenant_id | b3094e3ded7e4d6ea7b91b3641214a7a |
+----------------------+--------------------------------------+
test@localhost:~/devstack$
test@localhost:~/devstack$
test@localhost:~/devstack$ gbp l2policy-create new --l3-policy b
Created a new l2_policy:
+----------------------+--------------------------------------+
| Field | Value |
+----------------------+--------------------------------------+
| description | |
| id | 53c6c47c-ec65-4b74-80de-5941534d900b |
| l3_policy_id | f4c7258d-76cb-4e5e-bfc8-41f49de56120 |
| name | new |
| network_id | a12f6d59-dd80-42ab-9ab7-cf0fc6132b88 |
| policy_target_groups | |
| shared | False |
| tenant_id | b3094e3ded7e4d6ea7b91b3641214a7a |
+----------------------+--------------------------------------+
test@localhost:~/devstack$
test@localhost:~/devstack$ gbp policy-target-group-create new --l2-policy new
Service Unavailable (HTTP 503) (Request-ID: req-3f88174f-1dbc-428f-8c86-71c6138756c7)
test@localhost:~/devstack$
The fix for this is that the subnet-
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