Bug 1617745

Description of problem:

An exception during _startUnderlyingVm on an incoming migration leaves a VM running happily on the host and vdsm is NOT reporting it. So Down on RHV-M and Up on the host. This leaves space for data corruption if the VM has no lease.

The exception/error is being handled in BZ1598781. What is requested here is to better handle the exceptions so that if some other error occurs, at least the VM is killed to prevent a split brain.

1. During an incoming migration, VDSM failed to "start" the VM:

2018-08-16 10:15:39,271+1000 ERROR (vm/2e6bb483) [virt.vm] (vmId='2e6bb483-ff14-4743-8fc1-dcd41d644f15') The vm start process failed (vm:942)
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 871, in _startUnderlyingVm
    self._run()
  File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 2791, in _run
    self._setup_devices()
  File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 2615, in _setup_devices
    dev_object.setup()
  File "/usr/lib/python2.7/site-packages/vdsm/virt/vmdevices/graphics.py", line 91, in setup
    displaynetwork.create_network(display_network, self.vmid)
  File "/usr/lib/python2.7/site-packages/vdsm/virt/displaynetwork.py", line 27, in create_network
    libvirtnetwork.create_network(netname, display_device, user_reference)
  File "/usr/lib/python2.7/site-packages/vdsm/virt/libvirtnetwork.py", line 89, in create_network
    _createNetwork(createNetworkDef(netname, bridged, iface))
  File "/usr/lib/python2.7/site-packages/vdsm/virt/libvirtnetwork.py", line 108, in _createNetwork
    net.setAutostart(1)
  File "/usr/lib64/python2.7/site-packages/libvirt.py", line 2981, in setAutostart
    if ret == -1: raise libvirtError ('virNetworkSetAutostart() failed', net=self)
libvirtError: Failed to create symlink '/etc/libvirt/qemu/networks/autostart/vdsm-production.xml' to '/etc/libvirt/qemu/networks/vdsm-production.xml': File exists

2. VM is "down"

2018-08-16 10:15:39,271+1000 INFO  (vm/2e6bb483) [virt.vm] (vmId='2e6bb483-ff14-4743-8fc1-dcd41d644f15') Changed state to Down: Failed to create symlink '/etc/libvirt/qemu/networks/autostart/vdsm-production.xml' to '/etc/libvirt/qemu/networks/vdsm-production.xml': File exists (code=1) (vm:1682)

2018-08-16 10:15:39,277+1000 INFO  (vm/2e6bb483) [virt.vm] (vmId='2e6bb483-ff14-4743-8fc1-dcd41d644f15') Stopping connection (guestagent:438)

3. But migration finishes and VM runs:

Libvirt event saying the nigration finished and VM runs:

2018-08-16 10:15:48,621+1000 INFO  (libvirt/events) [virt.vm] (vmId='2e6bb483-ff14-4743-8fc1-dcd41d644f15') CPU running: onResume (vm:6157)
2018-08-16 10:15:48,635+1000 INFO  (libvirt/events) [virt.vm] (vmId='2e6bb483-ff14-4743-8fc1-dcd41d644f15') CPU running: onResume (vm:6157)

4. Destroy is called

2018-08-16 10:15:53,729+1000 INFO  (jsonrpc/0) [api.virt] START destroy(gracefulAttempts=1) from=::ffff:192.168.18.179,57282, vmId=2e6bb483-ff14-4743-8fc1-dcd41d644f15 (api:46)

2018-08-16 10:15:53,730+1000 INFO  (jsonrpc/0) [virt.vm] (vmId='2e6bb483-ff14-4743-8fc1-dcd41d644f15') Release VM resources (vm:5237)

2018-08-16 10:15:53,730+1000 WARN  (jsonrpc/0) [virt.vm] (vmId='2e6bb483-ff14-4743-8fc1-dcd41d644f15') trying to set state to Powering down when already Down (vm:606)

2018-08-16 10:15:53,730+1000 INFO  (jsonrpc/0) [virt.vm] (vmId='2e6bb483-ff14-4743-8fc1-dcd41d644f15') Stopping connection (guestagent:438)

5. VM is still running hours later

$ cat date 
Thu Aug 16 11:48:38 AEST 2018

$ grep 2e6bb483-ff14-4743-8fc1-dcd41d644f15 ps | wc -l
1

$ cat sos_commands/virsh/virsh_-r_list_--all  | grep NAS01 | wc -l
1

Version-Release number of selected component (if applicable):
vdsm-4.20.35-1.el7ev.x86_64

Actual results:
VDSM does not report a VM that is Up

Expected results:
VDSM kills the VM or report it as Up. Avoid split brain.