Adding some log snips with timestamps, maybe it will be usefull

server show fa265d0a-f38d-49f0-8b7d-1e0964f4c8df'
[2020-11-11 23:22:02,479] 427  DEBUG MainThread ssh.expect  :: Output: 
+-------------------------------------+----------------------------------------------------------+
| Field                               | Value                                                    |
+-------------------------------------+----------------------------------------------------------+
| OS-DCF:diskConfig                   | MANUAL                                                   |
| OS-EXT-AZ:availability_zone         | nova                                                     |
| OS-EXT-SRV-ATTR:host                | controller-0                                             |
| OS-EXT-SRV-ATTR:hypervisor_hostname | controller-0                                             |
| OS-EXT-SRV-ATTR:instance_name       | instance-00000005                                        |
| OS-EXT-STS:power_state              | Running                                                  |
| OS-EXT-STS:task_state               | None                                                     |
| OS-EXT-STS:vm_state                 | active                                                   |
| OS-SRV-USG:launched_at              | 2020-11-11T14:02:33.000000                               |

server show cab87397-fdc5-4a86-a66a-6597bd8d0768'
[2020-11-11 23:22:04,721] 427  DEBUG MainThread ssh.expect  :: Output: 
+-------------------------------------+----------------------------------------------------------+
| Field                               | Value                                                    |
+-------------------------------------+----------------------------------------------------------+
| OS-DCF:diskConfig                   | MANUAL                                                   |
| OS-EXT-AZ:availability_zone         | nova                                                     |
| OS-EXT-SRV-ATTR:host                | controller-1                                             |
| OS-EXT-SRV-ATTR:hypervisor_hostname | controller-1                                             |
| OS-EXT-SRV-ATTR:instance_name       | instance-00000007                                        |
| OS-EXT-STS:power_state              | Running                                                  |
| OS-EXT-STS:task_state               | None                                                     |
| OS-EXT-STS:vm_state                 | active                                                   |
| OS-SRV-USG:launched_at              | 2020-11-11T14:13:20.000000                               |

[2020-11-11 23:22:14,781] 305  DEBUG MainThread ssh.send    :: Send 'sudo reboot -f'
[2020-11-11 23:22:14,893] 190  INFO  MainThread host_helper.reboot_hosts:: Active controller reboot started.

server list'
[2020-11-11 23:24:49,821] 427  DEBUG MainThread ssh.expect  :: Output: 
+--------------------------------------+------------+--------+-------------------------+----------+-----------+
| ID                                   | Name       | Status | Networks                | Image    | Flavor    |
+--------------------------------------+------------+--------+-------------------------+----------+-----------+
| cab87397-fdc5-4a86-a66a-6597bd8d0768 | admin-vm-2 | ACTIVE | network-1=192.168.0.162 | cirros   | f1.small  |
| fa265d0a-f38d-49f0-8b7d-1e0964f4c8df | admin-vm-1 | ACTIVE | network-1=192.168.0.184 | centos-2 | f1.medium |
+--------------------------------------+------------+--------+-------------------------+----------+-----------+

host-list'
[2020-11-11 23:24:58,169] 427  DEBUG MainThread ssh.expect  :: Output: 
+----+--------------+-------------+----------------+-------------+--------------+
| id | hostname     | personality | administrative | operational | availability |
+----+--------------+-------------+----------------+-------------+--------------+
| 1  | controller-0 | controller  | unlocked       | disabled    | offline      |
| 2  | controller-1 | controller  | unlocked       | enabled     | available    |
+----+--------------+-------------+----------------+-------------+--------------+

server list --a'
[2020-11-11 23:25:55,140] 427  DEBUG MainThread ssh.expect  :: Output: 
+--------------------------------------+------------+--------+-------------------------+----------+-----------+
| ID                                   | Name       | Status | Networks                | Image    | Flavor    |
+--------------------------------------+------------+--------+-------------------------+----------+-----------+
| cab87397-fdc5-4a86-a66a-6597bd8d0768 | admin-vm-2 | ACTIVE | network-1=192.168.0.162 | cirros   | f1.small  |
| fa265d0a-f38d-49f0-8b7d-1e0964f4c8df | admin-vm-1 | ERROR  | network-1=192.168.0.184 | centos-2 | f1.medium |
+--------------------------------------+------------+--------+-------------------------+----------+-----------+

server list --a'
[2020-11-11 23:29:50,030] 427  DEBUG MainThread ssh.expect  :: Output: 
+--------------------------------------+------------+--------+-------------------------+----------+-----------+
| ID                                   | Name       | Status | Networks                | Image    | Flavor    |
+--------------------------------------+------------+--------+-------------------------+----------+-----------+
| cab87397-fdc5-4a86-a66a-6597bd8d0768 | admin-vm-2 | ACTIVE | network-1=192.168.0.162 | cirros   | f1.small  |
| fa265d0a-f38d-49f0-8b7d-1e0964f4c8df | admin-vm-1 | ACTIVE | network-1=192.168.0.184 | centos-2 | f1.medium |
+--------------------------------------+------------+--------+-------------------------+----------+-----------+

server show fa265d0a-f38d-49f0-8b7d-1e0964f4c8df'
[2020-11-11 23:29:52,391] 427  DEBUG MainThread ssh.expect  :: Output: 
+-------------------------------------+----------------------------------------------------------+
| Field                               | Value                                                    |
+-------------------------------------+----------------------------------------------------------+
| OS-DCF:diskConfig                   | MANUAL                                                   |
| OS-EXT-AZ:availability_zone         | nova                                                     |
| OS-EXT-SRV-ATTR:host                | controller-0                                             |
| OS-EXT-SRV-ATTR:hypervisor_hostname | controller-0                                             |
| OS-EXT-SRV-ATTR:instance_name       | instance-00000005                                        |
| OS-EXT-STS:power_state              | Running                                                  |
| OS-EXT-STS:task_state               | None                                                     |
| OS-EXT-STS:vm_state                 | active                                                   |
| OS-SRV-USG:launched_at              | 2020-11-11T14:02:33.000000                               |
controller-1:~$ 

Following VMs stayed on the same host controller-0: ['fa265d0a-f38d-49f0-8b7d-1e0964f4c8df']