While enabling maintenance mode i see random instances getting stopped while the host is evacuated, the majority is migrated without any issues. But sometimes i see a instance which should have been live migrated being stopped.

the management server says this

2026-04-13 10:26:54,986 INFO [c.c.h.HighAvailabilityManagerExtImpl] (HA-Worker-1:[ctx-7abbe53d, work-3314]) (logid:5ce65c99) Migration attempt: for VM VM instance {"id":4930,"instanceName":"i-55-4930-VM","state":"Running","type":"User","uuid":"cf19-00b6-465e-98f1-c63b4860498d"}from host Host {"id":18,"name":"XXXch02","type":"Routing","uuid":"dc51-a18d-4f7d-9a2e-7dfbb7a1b908"}. Starting attempt: 1/5 times. 2026-04-13 10:42:32,197 INFO [c.c.v.ClusteredVirtualMachineManagerImpl] (Work-Job-Executor-21:[ctx-1e4a3543, job-742712/job-743693, ctx-ff1f267b]) (logid:279e8d1b) Migrating VM instance {"id":4930,"instanceName":"i-55-4930-VM","state":"Running","type":"User","uuid":"cf19-00b6-465e-98f1-c63b4860498d"} to Dest[Zone(Id)-Pod(Id)-Cluster(Id)-Host(Id)-Storage(Volume(Id|Type-->Pool(Id))] : Dest[Zone(3)-Pod(3)-Cluster(3)-Host(18)-Storage()] 2026-04-13 10:42:32,349 WARN [c.c.v.ClusteredVirtualMachineManagerImpl] (Work-Job-Executor-21:[ctx-1e4a3543, job-742712/job-743693, ctx-ff1f267b]) (logid:279e8d1b) Unable to migrate VM instance {"id":4930,"instanceName":"i-55-4930-VM","state":"Running","type":"User","uuid":"cf19-00b6-465e-98f1-c63b4860498d"} to Host {"id":18,"name":"XXXch02","type":"Routing","uuid":"dc51-a18d-4f7d-9a2e-7dfbb7a1b908"} due to [Resource [Host:18] is unreachable: Host 18: Operation timed out] com.cloud.exception.AgentUnavailableException: Resource [Host:18] is unreachable: Host 18: Operation timed out 2026-04-13 10:43:27,247 INFO [c.c.r.ResourceManagerImpl] (AgentMonitor-1:[ctx-6e6b2b3f]) (logid:afd387b5) Attempting maintenance for Host {"id":21,"name":"XXXch03","type":"Routing","uuid":"eacf-b3e7-4aa9-b4ae-ff5a41862c06"} found pending migration for VM instance {"id":4930,"instanceName":"i-55-4930-VM","state":"Stopping","type":"User","uuid":"cf19-00b6-465e-98f1-c63b4860498d"}. 2026-04-13 10:43:40,248 ERROR [c.c.v.VmWorkJobHandlerProxy] (Work-Job-Executor-21:[ctx-1e4a3543, job-742712/job-743693, ctx-ff1f267b]) (logid:279e8d1b) Invocation exception, caused by: com.cloud.utils.exception.CloudRuntimeException: Unable to migrate VM instance {"id":4930,"instanceName":"i-55-4930-VM","state":"Running","type":"User","uuid":"cf19-00b6-465e-98f1-c63b4860498d"} 2026-04-13 10:43:40,248 INFO [c.c.v.VmWorkJobHandlerProxy] (Work-Job-Executor-21:[ctx-1e4a3543, job-742712/job-743693, ctx-ff1f267b]) (logid:279e8d1b) Rethrow exception com.cloud.utils.exception.CloudRuntimeException: Unable to migrate VM instance {"id":4930,"instanceName":"i-55-4930-VM","state":"Running","type":"User","uuid":"cf19-00b6-465e-98f1-c63b4860498d"} 2026-04-13 10:43:40,248 ERROR [c.c.v.VmWorkJobDispatcher] (Work-Job-Executor-21:[ctx-1e4a3543, job-742712/job-743693]) (logid:279e8d1b) Unable to complete AsyncJob {"accountId":1,"cmd":"com.cloud.vm.VmWorkMigrateAway","cmdInfo":"rO0ABXNyAB5jb20uY2xvdWQudm0uVm1Xb3JrTWlncmF0ZUF3YXmt4MX4jtcEmwIAAUoACXNyY0hvc3RJZHhyABNjb20uY2xvdWQudm0uVm1Xb3Jrn5m2VvAlZ2sCAARKAAlhY2NvdW50SWRKAAZ1c2VySWRKAAR2bUlkTAALaGFuZGxlck5hbWV0ABJMamF2YS9sYW5nL1N0cmluZzt4cAAAAAAAAAABAAAAAAAAAAEAAAAAAAATQnQAGVZpcnR1YWxNYWNoaW5lTWFuYWdlckltcGwAAAAAAAAAFQ","cmdVersion":0,"completeMsid":null,"created":"Mon Apr 13 10:42:31 UTC 2026","id":743693,"initMsid":90520733699643,"instanceId":null,"instanceType":null,"lastPolled":null,"lastUpdated":null,"processStatus":0,"removed":null,"result":null,"resultCode":0,"status":"IN_PROGRESS","userId":1,"uuid":"1401-8cf9-4276-ab57-c6a844371dd2"}, job origin: 742712 com.cloud.utils.exception.CloudRuntimeException: Unable to migrate VM instance {"id":4930,"instanceName":"i-55-4930-VM","state":"Running","type":"User","uuid":"cf19-00b6-465e-98f1-c63b4860498d"}

i would expect to just leave the instance alone up and running on its origin host and trigger a failure for the maintenance mode.

versions

ACS 4.22
Ubuntu 24.04
KVM