Re: Feature request? Auto start vm upon next shutdown

On 6/22/20 03:47, Marc Roos wrote: So here's the problem- in order for hardware changes to be detected/applied, you actually *do* need a destroy[0] operation as I understand it (a "poweroff" finishes-ish with a destroy, as does the ACPI shutdown, as dues a guest shutdown, etc. but NOT a guest reboot- it bypasses the destroy, which is precisely why domains' hardware changes do not simply show up when a reboot is issued in the guest), in libvirt parlance, not a reboot. I strongly suspect I am grossly oversimplifying the above, but it should be close enough. In order to do what you propose above, one would need at the least: 1.) A flag for the domain specifying only a single reboot after the very next time it does some sort of shutdown. a.) I suspect this is already available, in SOME form, as domains will reboot once the install is marked as finished. Whether this is a full destroy/start operation or merely an ACPI reboot, I don't know. 2.) A polling system that looks for domains that are defined but not running ("destroyed"). Check for flag in #1 and, if present, start the domain and remove #1's flag. I do not believe this sort of polling exists; I believe domain status is done on-demand. See above; in order to apply new hardware without a destroy/start operation, major swathes of code would need to be rewritten - *and* the guest operating system needs to be able to recognize new hardware changes on the fly. Many do not like this as, with specialized exceptions, it does not happen on physical hardware. I can see potentially this being implemented into VirtIO, but again - it would require the guest OS' awareness of that. But without that guest OS' awareness, you will need (should) still need to perform a proper shutdown regardless of how the hypervisor implements hardware changing. [0] "destroy" in hypervisors does not mean "delete" - or, in livirt terminology, "undefine"; it means "make this domain not-active". it's the "true" opposite of a start operation. I recommend reading the virsh(1) manpage. -- brent saner https://square-r00t.net/ GPG info: https://square-r00t.net/gpg-info