Description of the problem:
During RHOSP 17.1 to RHOSO 18.0 OVN migration, ovsdb-client restore fails with "transaction failed (End of file)" error when restoring OVN NB/SB databases.

Logs:
[root@xxx tmp]# cat ovn-sb-restore.log | tail -n 20
2026-01-05T07:42:11Z|13572|stream_ssl|DBG|client0-->ssl:172.30.7.133:6642 type 257 (1 bytes)
2026-01-05T07:42:11Z|13573|stream_ssl|DBG|client0-->ssl:172.30.7.133:6642 type 256 (5 bytes)
2026-01-05T07:42:11Z|13574|stream_ssl|DBG|client0-->ssl:172.30.7.133:6642 type 257 (1 bytes)
2026-01-05T07:42:11Z|13575|stream_ssl|DBG|client0-->ssl:172.30.7.133:6642 type 256 (5 bytes)
2026-01-05T07:42:11Z|13576|stream_ssl|DBG|client0-->ssl:172.30.7.133:6642 type 257 (1 bytes)
2026-01-05T07:42:17Z|13577|poll_loop|DBG|wakeup due to [POLLIN] on fd 3 (10.128.0.240:55962<->172.30.7.133:6642) at ../lib/stream-ssl.c:835 (1% CPU usage)
2026-01-05T07:42:17Z|13578|stream_ssl|DBG|client0<--ssl:172.30.7.133:6642 type 256 (5 bytes)
2026-01-05T07:42:17Z|13579|poll_loop|DBG|wakeup due to [POLLIN] on fd 3 (10.128.0.240:55962<->172.30.7.133:6642) at ../lib/stream-ssl.c:835 (1% CPU usage)
2026-01-05T07:42:17Z|13580|stream_ssl|DBG|client0<--ssl:172.30.7.133:6642 type 257 (1 bytes)
2026-01-05T07:42:17Z|13581|stream_ssl|DBG|client0<--ssl:172.30.7.133:6642 type 256 (5 bytes)
2026-01-05T07:42:17Z|13582|stream_ssl|DBG|client0<--ssl:172.30.7.133:6642 type 257 (1 bytes)
2026-01-05T07:42:17Z|13583|stream_ssl|DBG|client0<--ssl:172.30.7.133:6642 type 256 (5 bytes)
2026-01-05T07:42:17Z|13584|stream_ssl|DBG|client0<--ssl:172.30.7.133:6642 type 257 (1 bytes)
2026-01-05T07:42:17Z|13585|stream_ssl|DBG|client0<--ssl:172.30.7.133:6642 type 256 (5 bytes)
2026-01-05T07:42:18Z|13586|poll_loop|DBG|wakeup due to [POLLIN] on fd 3 (10.128.0.240:55962<->172.30.7.133:6642) at ../lib/stream-ssl.c:835 (1% CPU usage)
2026-01-05T07:42:18Z|13587|stream_ssl|DBG|client0-->ssl:172.30.7.133:6642 type 256 (5 bytes)
2026-01-05T07:42:18Z|13588|stream_ssl|DBG|client0-->ssl:172.30.7.133:6642 type 257 (1 bytes)
2026-01-05T07:42:18Z|13589|stream_ssl|DBG|client0-->ssl:172.30.7.133:6642 alert: warning, close_notify (2 bytes)
ovsdb-client: transaction failed (End of file)
command terminated with exit code 1

Root Cause:
Connection table configuration mismatch between source and target:
RHOSP 17.1 backup: pssl:6641:0.0.0.0 (IPv4)
RHOSO 18.0 fresh: pssl:6641:[::] (IPv6)

[root@xxxx chapter_3]# oc exec ovn-copy-data -n openstack – ovsdb-tool query /backup/ovs-sb.db   '["OVN_Southbound", {"op": "select", "table": "Connection", "where": []}]' | jq '.'
[
  {
    "rows": [
     

{         "_uuid": [           "uuid",           "c01ea1af-df34-43b3-b01d-ce7ec04ec09d"         ],         "_version": [           "uuid",           "8583525a-3994-47fc-91c3-96942cae1fd8"         ],         "external_ids": [           "map",           []         ],         "inactivity_probe": 60000,         "is_connected": false,         "max_backoff": [           "set",           []         ],         "other_config": [           "map",           []         ],         "read_only": false,         "role": "",         "status": [           "map",           []         ],         "target": "pssl:6642:0.0.0.0"       }

    ]
  }
]

 

[root@xxx chapter_3]# oc exec -n openstack ovsdbserver-sb-0 – ovn-sbctl list connection
Defaulted container "ovsdbserver-sb" out of: ovsdbserver-sb, openstack-network-exporter
_uuid               : 8f489214-15b4-4df1-9998-911c90a6ac41
external_ids        : {}
inactivity_probe    : 60000
is_connected        : false
max_backoff         : []
other_config        : {}
read_only           : false
role                : ""
status              : {}
target              : "pssl:6642:[::]"

So, when restore transaction includes Connection table change, server immediately reconfigures listening sockets, closing the client connection before sending the response.

So the workaround is to set target connection table to match the backup.