[pve-devel] pvedaemon hanging because of qga retry

Alexandre DERUMIER aderumier at odiso.com
Mon May 21 09:26:13 CEST 2018


> if think we shouldn't try to send after that the other command with 1 hour
> timeout...

>>Sure, once we run into a timeout we should not send the second command.

I have looked at libvirt/ovirt.

It seem that's it's possible to detect if agent is connected, through a qmp event VSERPORT_CHANGE.

https://git.qemu.org/?p=qemu.git;a=commit;h=e2ae6159
https://git.qemu.org/?p=qemu.git;a=blobdiff;f=docs/qmp/qmp-events.txt;h=d759d197486a3edf3b629fb11e9922ad92fb041a;hp=9d7439e3073ac63b639ce282c7466933ccb411b4;hb=032baddea36330384b3654fcbfafa74cc815471c;hpb=db52658b38fea4e54c23c9cfbced9478d368aa84

previously, they send a guest-ping with a short timeout before each command, and since this commit

https://www.redhat.com/archives/libvir-list/2014-November/msg00708.html

they catch the VSERPORT_CHANGE to known if the daemon is connected or not to the serial device.


We don't catch events currently, but maybe could we patch qemu to store the status somewhere instead event only,
and retrieve it with a qmp command before calling qga ?


----- Mail original -----
De: "dietmar" <dietmar at proxmox.com>
À: "aderumier" <aderumier at odiso.com>
Cc: "pve-devel" <pve-devel at pve.proxmox.com>
Envoyé: Dimanche 20 Mai 2018 15:51:37
Objet: Re: [pve-devel] pvedaemon hanging because of qga retry

> if the guest is so loaded, than it can't even send reponse to guest-ping (with 
> a "short" timeout of some seconds, not ms!), 

AFAIK this is quite common ... (unfortunately). We had several support cases in 
the past (several seconds delay), 
but I do not remember how to reproduce. I will ask the support team next week 
... 

> if think we shouldn't try to send after that the other command with 1 hour 
> timeout... 

Sure, once we run into a timeout we should not send the second command. 



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