Problem with vRouter after Livepatching from 4.20.1.0 -> 4.20.2.0

[jgotteswinter]

problem

The existing vRouter have been live patched from 4.20.1.0 to 4.20.2.0, everything shows up fine in the UI. The systemvm template used by the vRouter still shows 4.20.1.0, but the software version is correctly displayed with 4.20.2.0
Now, when i tried to start a vm, it failed with an error "Network is unavailable. Please contact administrator".

The cloudstack management servers log shows this

2025-12-09 11:40:35,705 ERROR [c.c.a.ApiAsyncJobDispatcher] (API-Job-Executor-92:[ctx-04bdbebb, job-717188]) (logid:8225e4c6) Unexpected exception while executing org.apache.cloudstack.api.command.admin.vm.StartVMCmdByAdmin com.cloud.utils.exception.CloudRuntimeException: Network is unavailable. Please contact administrator
...
...
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Caused by: com.cloud.exception.ResourceUnavailableException: Resource [VirtualRouter:5014] is unreachable: Unable to send command. Router requires upgrade

after rebooting the vRouter everything started working again. Live patching seems to be broken here, i had a similar effect a few days ago as well. After a reboot, the vRouter also uses the newer systemvm template 4.20.2.0

we are on Ubuntu 24.04, our vRouters are redundant.

[weizhouapache]

@jgotteswinter
can you check the global setting minreq.sysvmtemplate.version ?
if it is 4.20.2.0, change it to 4.20.1.0

[jgotteswinter]

yes its indeed 4.20.2.0, i guess this has been set by the update routines? I did not change it

[DaanHoogland]

@jgotteswinter , has the workaround @weizhouapache gave worked for you?

[abh1sar]

@jgotteswinter , has the workaround @weizhouapache gave worked for you?

@jgotteswinter did it work?

[jgotteswinter]

yes it worked after switching the template version. But, as i said, the newer template version was set by the update routines (i guess, i didnt check it). This breaks livepatching, the workaround is to switch the template version back to the previous one.

Thanks @weizhouapache for the hint

[DaanHoogland]

@weizhouapache , I think we can close this as it won’t be an issue in 20.3 anymore, can we?

[sudo87]

@weizhouapache @DaanHoogland is there any fix we need to add to address this issue?

[weizhouapache]

@weizhouapache @DaanHoogland is there any fix we need to add to address this issue?

@sudo87
I think no code changes are needed.
just check if the change of minreq.sysvmtemplate.version setting is mentioned in the section of VR live-patch in cloudstack doc, update doc if not found.

[sudo87]

Thank you @weizhouapache for your suggestion to update the document. We add note specifying what value should be set for config wrt VR template version in the following pr:
minreq.sysvmtemplate.version

Doc pr: apache/cloudstack-documentation#618