How does one solve the sanlock error reported when the oVirt VM is started ?, Ovirtsanlock

How does one solve the sanlock error reported when the oVirt VM is started ?, Ovirtsanlock

Symptom:

The VM has been in use for a period of time. The VM is shut down and an error occurs after it is started;

Background log:

Thread-570342: ERROR: 15:31:17, 944: vm: 761: virt. vm: :( _ startUnderlyingVm) vmId = '18988d57-d0d3-4ff5-9e3a-146f2de4b6f2 ': The vm start process failedTraceback (most recent call last): File "/usr/share/vdsm/virt/vm. py ", line 705, in _ startUnderlyingVm self. _ run () File "/usr/share/vdsm/virt/vm. py ", line 1944, in _ run self. _ connection. createXML (domxml, flags), File "/usr/lib/python2.7/site-packages/vdsm/lib1_connection. py ", line 124, in wrapper ret = f (* args, ** kwargs) File"/usr/lib/python2.7/site-packages/vdsm/utils. py ", line 1313, in wrapper return func (inst, * args, ** kwargs) File"/usr/lib64/python2.7/site-packages/libvirt. py ", line 3611, in createXML if ret is None: raise libvirtError ('virdomaincreatexml () failed', conn = self) libvirtError: Internal error: Process exited prior to exec: libvirt: lock Driver error: failed to open the slot for the sanlock daemon: refused to connect to Thread-570342: INFO: 15:31:17, 947: vm: 1332: virt. vm: :( setDownStatus) vmId = '18988d57-d0d3-4ff5-9e3a-146f2de4b6f2 ': Changed state to Down: Internal error: Process exited prior to exec: libvirt: Lock Driver> error: failed to open the slot for the sanlock daemon: Connection denied (code = 1)

sanlock.log 2018-02-05 15:37:59+0800 6554608 [135834]: sanlock daemon started 3.2.4 host 3c4a8445-6b22-42df-9b06-91d9774dae1d.host01 2018-02-05 15:37:59+0800 6554608 [135834]: set scheduler RR|RESET_ON_FORK priority 99 failed: Operation not permitted

Solution:

Restart the libmongod service because sanlock is used in libvirt.

Troubleshooting:

In sanlock, sched_setscheduler (2) causes sanlock to fail to schedule tasks in real time. When a machine experiences high load IO, sanlock will lose its deadlines.