Hook script and VM configuration

[Matthieu Le Corre]

Hi,
We are setting up a brand new PVE instance dedicated to our firewalls stacks.
All those FWs rely on VFs for there network interfaces.

The old solution was based on libvirt, and VFs could be dynamically attributed to VMs.

To mimick this behaviour I've setup an pre-start hook script that get info from the config.description and then setup the VF accordingly .
It check that the VF is not assigned to any VMs then feed the config file.

However, it seems that even if this a pre-start, configuration is already loaded from file and modification are not applied to the VM to be run.
I've also tried to use "qm config set" or "pvesh set" without any success as then both try to lock the VM and so, fail.

Is there a better way to handle that ?
Why does with pre-start the configuration is already lock ?

 

[Matthieu Le Corre]

I've looked at the QemuServer.pm code to check how the hook script is launch and found that is is simply run on the vm_start_nolock function.

I've added $conf = PVE::QemuConfig->load_config($vmid); at line 4964 of QemuServer.pm

Naively I thought that triggering a conf reload juste after that would solve my problem, but it not working.
My questions is, what's am I missing ?

PS: I've initially created this thread into the networking section of the forum, but it seems more a configuration situation, If some admin can move it,
this would be nice

 

[Matthieu Le Corre]

I reply to myself,
I juste need to add
PVE::Cluster::cfs_update() before re-loading the config !

 

[speeDDemon_AU]

Looking into this issue myself today, could you elaborate on any further changes you made to this

 

[Matthieu Le Corre]

I've not changed this patch since the beginning, it is still applied to pve 7.2.11

cat dynamic_configuration.patch
--- /root/QemuServer.pm    2021-03-22 15:29:28.955293274 +0100
+++ /usr/share/perl5/PVE/QemuServer.pm 2021-03-22 15:30:53.795779826 +0100
@@ -5029,6 +5029,12 @@
 
     PVE::GuestHelpers::exec_hookscript($conf, $vmid, 'pre-start', 1);
 
+    # DSIN-20220222: Patch a Mamatt
+    # update cache
+    PVE::Cluster::cfs_update();
+    # reload conf in case pre start update it
+    $conf = PVE::QemuConfig->load_config($vmid);
+
     my $forcemachine = $params->{forcemachine};
     my $forcecpu = $params->{forcecpu};
     if ($resume) {