[pve-devel] [PATCH qemu-server] resume: bump timeout for query-status

* [pve-devel] [PATCH qemu-server] resume: bump timeout for query-status
@ 2024-07-23 13:44 Fiona Ebner
  2024-07-25 12:33 ` Fiona Ebner
  0 siblings, 1 reply; 2+ messages in thread
From: Fiona Ebner @ 2024-07-23 13:44 UTC (permalink / raw)
  To: pve-devel

As reported in the community forum [0], after migration, the VM might
not immediately be able to respond to QMP commands, which means the VM
could fail to resume and stay in paused state on the target.

The reason seems to be that activating the block drives in QEMU can
take a bit of time. For example, it might be necessary to invalidate
the caches (where for raw devices a flush might be needed) and the
size of the block device needs to be queried.

In [0], an external Ceph cluster is used, but there doesn't seem to be
a flush. It also shows that the required timeout is a bit over 10
seconds, so use 60 to be on the safe side for the future.

All callers are inside workers or via the 'qm' CLI command, so bumping
beyond 30 seconds is fine.

[0]: https://forum.proxmox.com/threads/149610/

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
 PVE/QemuServer.pm | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index bf59b091..9e840912 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -6461,7 +6461,9 @@ sub vm_resume {
     my ($vmid, $skiplock, $nocheck) = @_;
 
     PVE::QemuConfig->lock_config($vmid, sub {
-	my $res = mon_cmd($vmid, 'query-status');
+	# After migration, the VM might not immediately be able to respond to QMP commands, because
+	# activating the block devices might take a bit of time.
+	my $res = mon_cmd($vmid, 'query-status', timeout => 60);
 	my $resume_cmd = 'cont';
 	my $reset = 0;
 	my $conf;
-- 
2.39.2



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