I have tried to reproduce this on a bionic stein deploy but couldn't. Can you take a look at the steps I went through and see of they roughly match what you were doing when you hit the issue ? Output below repeated in pastebin (https://paste.ubuntu.com/p/hBkzxy8cT4/): $ openstack hypervisor list +----+------------------------------------------------------+-----------------+-------------+-------+ | ID | Hypervisor Hostname | Hypervisor Type | Host IP | State | +----+------------------------------------------------------+-----------------+-------------+-------+ | 1 | juju-d21cc8-zaza-314b3c785bc4-17.project.serverstack | QEMU | 172.20.0.24 | up | | 2 | juju-d21cc8-zaza-314b3c785bc4-21.project.serverstack | QEMU | 172.20.0.29 | up | | 3 | juju-d21cc8-zaza-314b3c785bc4-19.project.serverstack | QEMU | 172.20.0.12 | up | | 4 | juju-d21cc8-zaza-314b3c785bc4-22.project.serverstack | QEMU | 172.20.0.30 | up | | 5 | juju-d21cc8-zaza-314b3c785bc4-23.project.serverstack | QEMU | 172.20.0.58 | up | | 6 | juju-d21cc8-zaza-314b3c785bc4-16.project.serverstack | QEMU | 172.20.0.23 | up | | 7 | juju-d21cc8-zaza-314b3c785bc4-24.project.serverstack | QEMU | 172.20.0.20 | up | | 8 | juju-d21cc8-zaza-314b3c785bc4-20.project.serverstack | QEMU | 172.20.0.47 | up | | 9 | juju-d21cc8-zaza-314b3c785bc4-18.project.serverstack | QEMU | 172.20.0.15 | up | +----+------------------------------------------------------+-----------------+-------------+-------+ $ openstack segment list +--------------------------------------+------+-------------+--------------+-----------------+ | uuid | name | description | service_type | recovery_method | +--------------------------------------+------+-------------+--------------+-----------------+ | b20022ad-3e09-474c-b759-b345aa96eda1 | seg0 | None | COMPUTE | auto | +--------------------------------------+------+-------------+--------------+-----------------+ $ openstack segment host list b20022ad-3e09-474c-b759-b345aa96eda1 +--------------------------------------+------------------------------------------------------+---------+--------------------+----------+----------------+--------------------------------------+ | uuid | name | type | control_attributes | reserved | on_maintenance | failover_segment_id | +--------------------------------------+------------------------------------------------------+---------+--------------------+----------+----------------+--------------------------------------+ | 05b12adb-767c-4436-b654-0d02a90b7d1c | juju-d21cc8-zaza-314b3c785bc4-18.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | cf94cd15-556f-4808-b5de-94e18a13c86d | juju-d21cc8-zaza-314b3c785bc4-20.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | feca5be9-39e8-4b04-a902-437d47996e2d | juju-d21cc8-zaza-314b3c785bc4-24.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | 5899472a-ecad-4630-877e-bc355ff851a2 | juju-d21cc8-zaza-314b3c785bc4-16.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | 047659e7-7d04-4af6-9225-7a34f1b25551 | juju-d21cc8-zaza-314b3c785bc4-23.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | 2cc8f62f-b7c3-4d4b-a997-07a3d93dc215 | juju-d21cc8-zaza-314b3c785bc4-22.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | bc8a9e57-34b1-486c-aeb9-8d7da8abe8c1 | juju-d21cc8-zaza-314b3c785bc4-19.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | 0bd4c253-26ef-4514-8774-c58916c1be3f | juju-d21cc8-zaza-314b3c785bc4-21.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | ef5c79a4-31c4-4d0a-aae1-0bba0ea4b2a5 | juju-d21cc8-zaza-314b3c785bc4-17.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | +--------------------------------------+------------------------------------------------------+---------+--------------------+----------+----------------+--------------------------------------+ $ openstack aggregate create ag1 +-------------------+----------------------------+ | Field | Value | +-------------------+----------------------------+ | availability_zone | None | | created_at | 2020-06-23T10:59:50.086633 | | deleted | False | | deleted_at | None | | hosts | None | | id | 1 | | name | ag1 | | properties | None | | updated_at | None | +-------------------+----------------------------+ $ openstack aggregate create ag2 +-------------------+----------------------------+ | Field | Value | +-------------------+----------------------------+ | availability_zone | None | | created_at | 2020-06-23T10:59:53.193578 | | deleted | False | | deleted_at | None | | hosts | None | | id | 2 | | name | ag2 | | properties | None | | updated_at | None | +-------------------+----------------------------+ $ openstack aggregate create ag3 +-------------------+----------------------------+ | Field | Value | +-------------------+----------------------------+ | availability_zone | None | | created_at | 2020-06-23T10:59:57.500132 | | deleted | False | | deleted_at | None | | hosts | None | | id | 3 | | name | ag3 | | properties | None | | updated_at | None | +-------------------+----------------------------+ $ openstack aggregate set --zone az1 ag1 $ openstack aggregate set --zone az2 ag2 $ openstack aggregate set --zone az3 ag3 $ openstack aggregate add host ag1 juju-d21cc8-zaza-314b3c785bc4-16.project.serverstack +-------------------+------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------+ | availability_zone | az1 | | created_at | 2020-06-23T10:59:50.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-16.project.serverstack | | id | 1 | | name | ag1 | | properties | availability_zone='az1' | | updated_at | None | +-------------------+------------------------------------------------------+ $ openstack aggregate add host ag1 juju-d21cc8-zaza-314b3c785bc4-17.project.serverstack +-------------------+------------------------------------------------------------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------------------------------------------------------------+ | availability_zone | az1 | | created_at | 2020-06-23T10:59:50.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-16.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-17.project.serverstack | | id | 1 | | name | ag1 | | properties | availability_zone='az1' | | updated_at | None | +-------------------+------------------------------------------------------------------------------------------------------------+ $ openstack aggregate add host ag1 juju-d21cc8-zaza-314b3c785bc4-18.project.serverstack +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | availability_zone | az1 | | created_at | 2020-06-23T10:59:50.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-16.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-17.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-18.project.serverstack | | id | 1 | | name | ag1 | | properties | availability_zone='az1' | | updated_at | None | +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ $ openstack aggregate add host ag2 juju-d21cc8-zaza-314b3c785bc4-19.project.serverstack +-------------------+------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------+ | availability_zone | az2 | | created_at | 2020-06-23T10:59:53.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-19.project.serverstack | | id | 2 | | name | ag2 | | properties | availability_zone='az2' | | updated_at | None | +-------------------+------------------------------------------------------+ $ openstack aggregate add host ag2 juju-d21cc8-zaza-314b3c785bc4-20.project.serverstack +-------------------+------------------------------------------------------------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------------------------------------------------------------+ | availability_zone | az2 | | created_at | 2020-06-23T10:59:53.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-19.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-20.project.serverstack | | id | 2 | | name | ag2 | | properties | availability_zone='az2' | | updated_at | None | +-------------------+------------------------------------------------------------------------------------------------------------+ $ openstack aggregate add host ag2 juju-d21cc8-zaza-314b3c785bc4-21.project.serverstack +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | availability_zone | az2 | | created_at | 2020-06-23T10:59:53.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-19.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-20.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-21.project.serverstack | | id | 2 | | name | ag2 | | properties | availability_zone='az2' | | updated_at | None | +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ $ openstack aggregate add host ag3 juju-d21cc8-zaza-314b3c785bc4-22.project.serverstack +-------------------+------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------+ | availability_zone | az3 | | created_at | 2020-06-23T10:59:58.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-22.project.serverstack | | id | 3 | | name | ag3 | | properties | availability_zone='az3' | | updated_at | None | +-------------------+------------------------------------------------------+ $ openstack aggregate add host ag3 juju-d21cc8-zaza-314b3c785bc4-23.project.serverstack +-------------------+------------------------------------------------------------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------------------------------------------------------------+ | availability_zone | az3 | | created_at | 2020-06-23T10:59:58.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-22.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-23.project.serverstack | | id | 3 | | name | ag3 | | properties | availability_zone='az3' | | updated_at | None | +-------------------+------------------------------------------------------------------------------------------------------------+ $ openstack aggregate add host ag3 juju-d21cc8-zaza-314b3c785bc4-24.project.serverstack +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Field | Value | +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | availability_zone | az3 | | created_at | 2020-06-23T10:59:58.000000 | | deleted | False | | deleted_at | None | | hosts | juju-d21cc8-zaza-314b3c785bc4-22.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-23.project.serverstack, juju-d21cc8-zaza-314b3c785bc4-24.project.serverstack | | id | 3 | | name | ag3 | | properties | availability_zone='az3' | | updated_at | None | +-------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+ $ openstack hypervisor list +----+------------------------------------------------------+-----------------+-------------+-------+ | ID | Hypervisor Hostname | Hypervisor Type | Host IP | State | +----+------------------------------------------------------+-----------------+-------------+-------+ | 1 | juju-d21cc8-zaza-314b3c785bc4-17.project.serverstack | QEMU | 172.20.0.24 | up | | 2 | juju-d21cc8-zaza-314b3c785bc4-21.project.serverstack | QEMU | 172.20.0.29 | up | | 3 | juju-d21cc8-zaza-314b3c785bc4-19.project.serverstack | QEMU | 172.20.0.12 | up | | 4 | juju-d21cc8-zaza-314b3c785bc4-22.project.serverstack | QEMU | 172.20.0.30 | up | | 5 | juju-d21cc8-zaza-314b3c785bc4-23.project.serverstack | QEMU | 172.20.0.58 | up | | 6 | juju-d21cc8-zaza-314b3c785bc4-16.project.serverstack | QEMU | 172.20.0.23 | up | | 7 | juju-d21cc8-zaza-314b3c785bc4-24.project.serverstack | QEMU | 172.20.0.20 | up | | 8 | juju-d21cc8-zaza-314b3c785bc4-20.project.serverstack | QEMU | 172.20.0.47 | up | | 9 | juju-d21cc8-zaza-314b3c785bc4-18.project.serverstack | QEMU | 172.20.0.15 | up | +----+------------------------------------------------------+-----------------+-------------+-------+ $ openstack segment host list b20022ad-3e09-474c-b759-b345aa96eda1 +--------------------------------------+------------------------------------------------------+---------+--------------------+----------+----------------+--------------------------------------+ | uuid | name | type | control_attributes | reserved | on_maintenance | failover_segment_id | +--------------------------------------+------------------------------------------------------+---------+--------------------+----------+----------------+--------------------------------------+ | 05b12adb-767c-4436-b654-0d02a90b7d1c | juju-d21cc8-zaza-314b3c785bc4-18.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | cf94cd15-556f-4808-b5de-94e18a13c86d | juju-d21cc8-zaza-314b3c785bc4-20.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | feca5be9-39e8-4b04-a902-437d47996e2d | juju-d21cc8-zaza-314b3c785bc4-24.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | 5899472a-ecad-4630-877e-bc355ff851a2 | juju-d21cc8-zaza-314b3c785bc4-16.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | 047659e7-7d04-4af6-9225-7a34f1b25551 | juju-d21cc8-zaza-314b3c785bc4-23.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | 2cc8f62f-b7c3-4d4b-a997-07a3d93dc215 | juju-d21cc8-zaza-314b3c785bc4-22.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | bc8a9e57-34b1-486c-aeb9-8d7da8abe8c1 | juju-d21cc8-zaza-314b3c785bc4-19.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | 0bd4c253-26ef-4514-8774-c58916c1be3f | juju-d21cc8-zaza-314b3c785bc4-21.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | | ef5c79a4-31c4-4d0a-aae1-0bba0ea4b2a5 | juju-d21cc8-zaza-314b3c785bc4-17.project.serverstack | COMPUTE | SSH | False | False | b20022ad-3e09-474c-b759-b345aa96eda1 | +--------------------------------------+------------------------------------------------------+---------+--------------------+----------+----------------+--------------------------------------+