[pve-devel] [PATCH qemu-server] qm agent : check if qga service is running

[Thomas Lamprecht]

On 5/30/18 8:04 AM, Alexandre DERUMIER wrote:
>>> check running uses the ping command, so maybe we should exempt it here and always 
>>> to it - may not make sense to check with ping if we can do ping, or what do you mean? 
> 
> We need to check if qga is running with a small timeout (guest-ping) before doing another command with a bigger timeout (like freeze-fs / 1h timeout).
> The only wait to test is to send a command to qga (can be a ping or another command) or retreive qmp event but we don't have the framework to do it currently.
> 

That's clear, I understood that.
Just though that if a user wants to do a guest-ping it could be a bit weird
that we do not execute it directly but check first with the same command, i.e.,
ping, if we QGA is running - I meant to just if it makes sense to add a exception
from this test if the command itself is ping too, but not to important.

> 
> 
>>> So I actually get: 
>>>
>>> # pvesh create nodes/dev5/qemu/12312321/agent/fstrim 
>>> Qemu Guest Agent is not running - VM 12312321 qmp command 'guest-ping' failed - got timeout 
>>> Qemu Guest Agent is not running 
>>>
>>> We could add a $silent parameter to qga_check_running to avoid that. 
> 
> maybe could we simply change the warn in
> 
> sub qga_check_running {
>     my ($vmid) = @_;
> 
>    eval { vm_mon_cmd($vmid, "guest-ping", timeout => 3); };
>     if ($@) {
>         warn "Qemu Guest Agent is not running - $@";
>         return 0;
>     }
>     return 1;
> }
> 
> 
> -> warn "Qemu Guest Agent is not running";
> 
> 
> 
> and in Agent.pm,
> 
> return if !PVE::QemuServer::qga_check_running($vmid); 
> 
> ?
> 

I actually want to keep $@ as it makes sense for the other places where we call
qga_check_running. I'll do a follow up.

> 
> 
> 
> ----- Mail original -----
> De: "Thomas Lamprecht" <t.lamprecht at proxmox.com>
> À: "pve-devel" <pve-devel at pve.proxmox.com>, "aderumier" <aderumier at odiso.com>
> Envoyé: Mercredi 30 Mai 2018 07:49:00
> Objet: Re: [pve-devel] [PATCH qemu-server] qm agent : check if qga service is running
> 
> I'll agree with the patches intent, two notes inline 
> 
> On 5/28/18 5:36 PM, Alexandre Derumier wrote: 
>> --- 
>> PVE/API2/Qemu/Agent.pm | 1 + 
>> 1 file changed, 1 insertion(+) 
>>
>> diff --git a/PVE/API2/Qemu/Agent.pm b/PVE/API2/Qemu/Agent.pm 
>> index 9af5d5f..fbc8105 100644 
>> --- a/PVE/API2/Qemu/Agent.pm 
>> +++ b/PVE/API2/Qemu/Agent.pm 
>> @@ -174,6 +174,7 @@ sub register_command { 
>>
>> die "No Qemu Guest Agent\n" if !defined($conf->{agent}); 
>> die "VM $vmid is not running\n" if !PVE::QemuServer::check_running($vmid); 
>> + die "Qemu Guest Agent is not running\n" if !PVE::QemuServer::qga_check_running($vmid); 
> 
> check running uses the ping command, so maybe we should exempt it here and always 
> to it - may not make sense to check with ping if we can do ping, or what do you mean? 
> 
> Further, qga_check_running always does a: warn "Qemu Guest Agent is not running - $@"; 
> 
> So I actually get: 
> 
> # pvesh create nodes/dev5/qemu/12312321/agent/fstrim 
> Qemu Guest Agent is not running - VM 12312321 qmp command 'guest-ping' failed - got timeout 
> Qemu Guest Agent is not running 
> 
> We could add a $silent parameter to qga_check_running to avoid that. 
> 
>>
>> my $cmd = $param->{command} // $command; 
>> my $res = PVE::QemuServer::vm_mon_cmd($vmid, "guest-$cmd"); 
>>
> 
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