Lots of Warnings from VSANMGMTSVC

[chris_eagan]

Recently, I noticed a very large number of warnings in our ESXi logs coming from vsanmgmtd. The servers are running VMware ESXi, 7.0.2, 17630552, managed by vCenter Server, 7.0.2, 17694817. The /var/log/vsanmgmt.log contains this set of messages about 17000 times per day:

2021-04-27T18:13:01.329Z warning vsand[2561795] [opID=MainThread cliutils::SubscribeStatusCallback] CMMDS RegisterStatus
Callback failed because Failure.
2021-04-27T18:13:01.337Z error vsand[2561795] [opID=MainThread VsanHostHelper::isWitnessHost] vsi.get /vmkModules/vsanut
il/isWitness exception becasue of Bad parameter.
2021-04-27T18:13:06.339Z warning vsand[2561795] [opID=MainThread cliutils::SubscribeStatusCallback] CMMDS RegisterStatus
Callback failed because Failure.
2021-04-27T18:13:06.351Z error vsand[2561795] [opID=MainThread VsanHostHelper::isWitnessHost] vsi.get /vmkModules/vsanut
il/isWitness exception becasue of Bad parameter.
2021-04-27T18:13:08.593Z info vsand[2561821] [opID=Thread-2 VsanSystemImpl::_ConfigInfoPrintLog] configInfo: skipped
2021-04-27T18:13:08.594Z info vsand[2561821] [opID=Thread-2 VsanSystemImpl::_ConfigInfoPrintLog] configInfo: skipped​

The /var/log/vsansystem.log file contains this line the same number of times the other entries appear.

2021-04-27T18:15:26.682Z warning vsansystem[2561795] [vSAN@6876 sub=Libs] open(/dev/cmmds): No such file or directory

I checked and it is true that the /dev/cmmds file does not exist. Also, I ran vsish to check the /vmkModules/vsanutil/isWitness, and /vmkModules/vsanutil does not exist.

Any ideas on how to address these warnings are welcome!

[skinman3485]

We are getting the exact same set of errors in /var/log/vsanmgmt.log, with the same coinciding errors in  /var/log/vsansystem.log. 

Interestingly enough we are only seeing these errors on one host in our cluster. 

Has anyone found out a fix or explanation for these errors. 

[chris_eagan]

On our setup, the vsanmgmtsvc service produces many log entries whenever it is running.

We think that the vsanmgmtsvc is used for monitoring and managing vSAN. However, if vSAN isn't installed, there doesn't seem to be a good reason to have the monitoring service running, and when the monitoring service tries to find vSAN it can't, so it produces a bunch of messages.

If you are not using vSAN in your environment, we believe it is safe to disable the service.