Feature request: VMS systems should respond to virsh shutdown and reboot commands from the KVM host

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vaxman65
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Feature request: VMS systems should respond to virsh shutdown and reboot commands from the KVM host

Post by vaxman65 » Tue May 09, 2023 6:52 pm

In my tests so far, it appears that VMS systems created under KVM do not respond to the virsh commands for shutdown or reboot. Having these options supported is quite handy for centralized management defined at the hypervisor level. Some operations are just easier to co-ordinate from the central point, particularly if multiple systems are involved.

Aside from making it easier to deal with maintenance events on the KVM host, some activates involving single systems are more easily dealt with from the KVM host. For example, I put together a set of scripts that allow me to quickly take a cold snapshot of a guest system with 100% certainty that all data is flushed to disk.It leverages LVM snapshots on the host, but it ensures complete integrity by first shutting down the guest before taking the snapshots. The true state of the guest is easily tracked on the KVM host to make certain the shutdown is complete before the snapshot is take. Once the snapshots are taken, the guest is quickly restarted (if it was up and running to begin with). All together, the guest is down for just a handful of seconds in this operation.

This is but one example where it is easier for the KVM host to understand the overall management state for operations requiring coordination of activities on the KVM host and the VMS guest.


sodjan
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Re: Feature request: VMS systems should respond to virsh shutdown and reboot commands from the KVM host

Post by sodjan » Wed May 10, 2023 6:16 am

I see what you are saying... :-)

But I'm not sure many VMS sites would like a possibility to "pull the rug from under the feet" from their VMS systems in that way.

And besides, why do you need to make a snapshot of the guest system in that way?
Your VMS system will have it's own backup routines and they usually run on-line.

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martin
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Re: Feature request: VMS systems should respond to virsh shutdown and reboot commands from the KVM host

Post by martin » Wed May 10, 2023 7:21 am

Surely though allowing virsh to tell VMS to shutdown is not "pulling the run from under it", but warning the system to shut down cleanly. If you can issue virsh commands you have effectively got full control anyhow, try a "forced shutdown". Even worse, if you shut down the host machine and VMS ignores requests to stop, then sooner of later the host will simply stop.

Agreed about backups though.
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  • Started on a VAX 11/782 in 1984 with VMS 3.6.


dgordon
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Re: Feature request: VMS systems should respond to virsh shutdown and reboot commands from the KVM host

Post by dgordon » Wed May 10, 2023 7:53 am

Graceful shutdown of a VMS guest by request from the host is certainly on the list.
Executive Vice President of InfoServer Engineering at VSI.


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Re: Feature request: VMS systems should respond to virsh shutdown and reboot commands from the KVM host

Post by cgrant » Wed May 10, 2023 12:58 pm

Official problem report entered. Other ACPI-related functions, for example reset, are working so there is something specific to the shutdown itself that we are mishandling. Thanks for the report.

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