Red Hat Bugzilla – Bug 1341415
'virsh event' can not capture disk-change events
Last modified: 2016-11-03 14:46:09 EDT
Description of problem: 'virsh event' can not capture disk-change events Version-Release number of selected component (if applicable): libvirt-1.3.4-1.el7.x86_64 qemu-kvm-rhev-2.6.0-4.el7.x86_64 How reproducible: 100% Steps to Reproduce: 1.Edit the guest xml with optional startupPolicy,(rhel7.1.qcow2-non is a non-exist disk). ... <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/var/lib/libvirt/rhel7.1.qcow2-non' startupPolicy='optional'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> </disk> ..... 2.Open the second terminal, run the 'event-test.py' python script to catch the event # python /usr/share/doc/libvirt-python-1.3.4/examples/event-test.py qemu:///system Using uri:qemu:///system 3.Open third terminal, run the 'virsh event' command to catch the events #virsh event --all --loop 4.Start the guest : #virsh start testvm 5. Check log about disk-change in the libvirtd.log: #cat /var/log/libvirt/libvirtd.log | grep -i change 2016-05-31 09:41:32.247+0000: 513: debug : udevEventHandleCallback:1548 : udev action: 'change' 2016-05-31 09:41:36.691+0000: 518: info : virObjectNew:202 : OBJECT_NEW: obj=0x7fdc30001010 classname=virDomainEventDiskChange 2016-05-31 09:41:36.691+0000: 518: debug : virDomainEventDiskChangeDispose:474 : obj=0x7fdc30001010 2016-05-31 09:41:36.970+0000: 513: debug : udevEventHandleCallback:1548 : udev action: 'change' Actual results: No disk-change events show in the 2nd terminal & 3rd terminal. Expected results: 'virsh event' should be able to capture disk-change events: (2nd terminal) # python /usr/share/doc/libvirt-python-1.2.15/examples/event-test.py qemu:///system Using uri:qemu:///system myDomainEventDiskChangeCallback: Domain testvm(4) disk change oldSrcPath: /var/lib/libvirt/images/rhel7.1.qcow2-non newSrcPath: None devAlias: virtio-disk0 reason: 1 (3rd terminal):# virsh events --all --loop event 'disk-change' for domain testvm disk virtio-disk0: /var/lib/libvirt/images/rhel7.1.qcow2-non -> <null>: dropped Additional info: 1.It works well with libvirt-1.2.17-13.el7.x86_64.
Fixed upstream: commit 9cda91d6f6b887c6f06868f4d2fb16c288ae20d5 Author: Peter Krempa <pkrempa@redhat.com> Date: Thu Jun 2 15:32:00 2016 +0200 qemu: process: Call disk startup policy check after cloning domain def In commit 1e38ef72 the disk startup policy check was moved prior to the call to virDomainObjSetDefTransient which dropped the disk from the config rather than the def to be started which is a bug. Additionally we'd not report the disk change event for this since the disk aliases were not set at that point. Finally 'volume' based disks would not work with startup policy too. Fix it by moving it back after the definition is copied, aliases are assigned and disk sources are translated.
Reproduced with libvirt-1.3.4-1.el7.x86_64. steps are as comment 0. Verify pass with libvirt-2.0.0-1.el7.x86_64. Test steps: 1.Edit the guest xml with optional startupPolicy,(no-disk.qcow2 is a non-exist disk). ... <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/var/lib/libvirt/no-disk.qcow2' startupPolicy='optional'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> </disk> ..... 2.Open the second terminal, run the 'event-test.py' python script to catch the events # python /usr/share/doc/libvirt-python-2.0.0/examples/event-test.py qemu:///system Using uri:qemu:///system 3.Open third terminal, run the 'virsh event' command to catch the events #virsh event --all --loop 4.Start the guest : #virsh start rhel7.3 5.Check the output in the second terminal, can see the disk-chanage event: myDomainEventDiskChangeCallback: Domain rhel7.3(123) disk change oldSrcPath: /var/lib/libvirt/images/no-disk.qcow2 newSrcPath: None devAlias: virtio-disk1 reason: 1 6.Check the output in the third terminal,also can see the disk-change event: event 'disk-change' for domain rhel7.3 disk virtio-disk1: /var/lib/libvirt/images/no-disk.qcow2 -> <null>: dropped 7.Also test cdrom/floppy with 'file' type, also can see the disk-change event.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHSA-2016-2577.html