Re: xl create/save throwing errors

[Jan Beulich <jbeulich@xxxxxxxx>]

On 19.02.2025 17:04, Petr Beneš wrote:
> Hello,
> 
> I have a script that's supposed to start a couple of (Windows 10) VMs
> in parallel, wait until they boot and connect to the network, and then
> create a live snapshot.
> 
> VMs are created by simple "xl create vm.cfg" and the live snapshot is
> created by "xl save win10-18362-NNN path/to/state".
> 
> I have noticed, that "xl create" occasionally throws this line:
> ```
> libxl: error: libxl_aoutils.c:646:libxl__kill_xs_path: qemu
> command-line probe already exited
> ```
> 
> First I thought it's related to the fact that multiple "xl create"
> commands are being run in parallel, but to my surprise, this line
> sometimes occurs even for standalone "xl create" commands.
> 
> However, when "xl save" is being executed in parallel, I'm very often
> met with output similar to this:
> ```
> Saving to win10-18362-102/state new xl format (info 0x3/0x0/1780)
> xc: info: Saving domain 193, type x86 HVM
> Saving to win10-18362-101/state new xl format (info 0x3/0x0/1780)
> xc: info: Saving domain 192, type x86 HVM
> Saving to win10-18362-104/state new xl format (info 0x3/0x0/1780)
> xc: info: Saving domain 194, type x86 HVM
> xc: error: save callback suspend() failed: 0: Internal error
> xc: error: Save failed (0 = Success): Internal error
> libxl: error: libxl_stream_write.c:347:libxl__xc_domain_save_done:
> Domain 192:saving domain: domain responded to suspend request: Success
> Failed to save domain, resuming domain
> xc: error: save callback suspend() failed: 0: Internal error
> xc: error: Save failed (0 = Success): Internal error
> xc: error: Dom 192 not suspended: (shutdown 4, reason 3): Internal error
> libxl: error: libxl_dom_suspend.c:661:domain_resume_done: Domain
> 192:xc_domain_resume failed: Invalid argument
> libxl: error: libxl_stream_write.c:347:libxl__xc_domain_save_done:
> Domain 194:saving domain: domain responded to suspend request: Success
> Failed to save domain, resuming domain
> xc: error: Dom 194 not suspended: (shutdown 4, reason 3): Internal error
> libxl: error: libxl_dom_suspend.c:661:domain_resume_done: Domain
> 194:xc_domain_resume failed: Invalid argument
> xc: Frames: 1044480/1044480  100%: Frames: 52224/1044480    5%
> ```

Just one thing - to (hopefully) get a better understanding of the origin of
those errors, you may want to increase verbosity of the "xl save", e.g.
"xl -vvv save".

Jan