kvm: use ACPI and signal based reboot on KVM

[yadvr]

This replace the legacy stop/start logic with libvirt's native reboot
operation that will use ACPI and signal based rebooting of VM on KVM
hosts.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

[weizhouapache]

@rhtyd
if acpi is turned off inside vm, will it work ?

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/high_availability_add-on_reference/s1-acpi-CA#s2-bios-setting-CA

[wido]

I'm ok with this.

Any modern distro has ACPI enabled and should respond to it. Nowadays it's usually systemd handling this but in older versions it's acpid.

[mlsorensen]

If ACPI is off in the guest, that would apparently fail for any hypervisor that is using ACPI triggers to reboot. I haven't checked myself but I've been told that the Xen and VMware use ACPI triggers for the reboot API as well, and I think it would be expected behavior.

If it becomes an issue for KVM users who are accustomed to the current behavior, perhaps there can be a 'forced' option like stopVirtualMachine has, and that can be a shortcut to a full stop and start, so the various plugin workflows are properly called.

[weizhouapache]

If ACPI is off in the guest, that would apparently fail for any hypervisor that is using ACPI triggers to reboot. I haven't checked myself but I've been told that the Xen and VMware use ACPI triggers for the reboot API as well, and I think it would be expected behavior.

If it becomes an issue for KVM users who are accustomed to the current behavior, perhaps there can be a 'forced' option like stopVirtualMachine has, and that can be a shortcut to a full stop and start, so the various plugin workflows are properly called.

@rhtyd it would be nice to have 'forced' option as @mlsorensen said.

[yadvr]

That sounds sensible, thanks @mlsorensen @weizhouapache I'll update the logic to perform ACPI reboot (default), and if a forced API arg is provided do a stop + start (at the orchestration level, not in hypervisor plugin).

[DaanHoogland]

code here looks good, are you still implementing the stop / start in this PR @rhtyd , or is that somewhere else?

[sureshanaparti]

code here looks good, are you still implementing the stop / start in this PR @rhtyd , or is that somewhere else?

@DaanHoogland @rhtyd Addressed the suggested changes on the PR: #4681 , which provides the forced reboot option (to stop and start VM), along with ACPI reboot for KVM VM.

[yadvr]

Closing this old PR, in favour of the new