On Mon, Oct 28, 2013 at 01:03:49PM -0400, Cole Robinson wrote:
On 10/28/2013 07:52 AM, Daniel P. Berrange wrote:
From: "Daniel P. Berrange" <berrange@redhat.com>
The following sequence
1. Define a persistent QMEU guest 2. Start the QEMU guest 3. Stop libvirtd 4. Kill the QEMU process 5. Start libvirtd 6. List persistent guets
At the last step, the previously running persistent guest will be missing. This is because of a race condition in the QEMU driver startup code. It does
1. Load all VM state files 2. Spawn thread to reconnect to each VM 3. Load all VM config files
Only at the end of step 3, does the 'virDomainObjPtr' get marked as "persistent". There is therefore a window where the thread reconnecting to the VM will remove the persistent VM from the list.
The easy fix is to simply switch the order of steps 2 & 3.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- src/qemu/qemu_driver.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index c613967..9c3daad 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -816,8 +816,6 @@ qemuStateInitialize(bool privileged,
conn = virConnectOpen(cfg->uri);
- qemuProcessReconnectAll(conn, qemu_driver); - /* Then inactive persistent configs */ if (virDomainObjListLoadAllConfigs(qemu_driver->domains, cfg->configDir, @@ -828,6 +826,7 @@ qemuStateInitialize(bool privileged, NULL, NULL) < 0) goto error;
+ qemuProcessReconnectAll(conn, qemu_driver);
virDomainObjListForEach(qemu_driver->domains, qemuDomainSnapshotLoad,
I tried testing this patch to see if it would fix:
https://bugzilla.redhat.com/show_bug.cgi?id=1015246
from current master I did:
git revert a924d9d083c215df6044387057c501d9aa338b96 reproduce the bug git am <your-patch>
But the daemon won't even start up after your patch is built:
(gdb) bt #0 qemuMonitorOpen (vm=vm@entry=0x7fffd4211090, config=0x0, json=false, cb=cb@entry=0x7fffddcae720 <monitorCallbacks>, opaque=opaque@entry=0x7fffd419b840) at qemu/qemu_monitor.c:852 #1 0x00007fffdda1083d in qemuConnectMonitor ( driver=driver@entry=0x7fffd419b840, vm=vm@entry=0x7fffd4211090, logfd=logfd@entry=-1) at qemu/qemu_process.c:1412 #2 0x00007fffdda1685a in qemuProcessReconnect ( opaque=opaque@entry=0x7fffd422fef0) at qemu/qemu_process.c:3086 #3 0x00007ffff7528dce in virThreadHelper (data=<optimized out>) at util/virthreadpthread.c:161 #4 0x00007ffff4782f33 in start_thread (arg=0x7fffcb7fe700) at pthread_create.c:309 #5 0x00007ffff40a9ead in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
What is this trace showing ? or rather what is the error reported when it fails to start ? Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|