Instance in ERROR State, Write Lock on Disk File

Problem

The OpenStack instance fails to start and goes in ERROR state because of a write lock on the disk file of the instance. The following error can be seen in the ostackhost.log .

561 TRACE oslo_messaging.rpc.server libvirtError: internal error: qemu unexpectedly closed the monitor: XXXX-XX-XXTXX:XX:XX.084234Z qemu-kvm: -drive file=/mnt/nfs/instances/0e4d3940-d7c7-410f-b3f1-72ffda4d5605/disk,format=qcow2,if=none,id=drive-virtio-disk0,cache=none: Failed to get "write" lock

Environment

  • Platform9 Managed OpenStack - v3.6.0 and Higher

Cause

Another process on the host is performing I/O operations on the disk file which causes the instance to fail during the start process as it cannot get a write-lock on the disk file.

Resolution

  1. Check the hostname for the OpenStack instance.

# [root@testregion.platform9.net user(admin)]# openstack server show 0e4d3940-d7c7-410f-b3f1-72ffda4d5605+-------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------+| Field | Value |+-------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------+| OS-DCF:diskConfig | MANUAL || OS-EXT-AZ:availability_zone | HA-Win || OS-EXT-PF9-SRV-RES-INFO:res_info | {u'cfg_disk_gb': 60.0, u'vcpus': 6, u'cfg_memory_mb': 32768, u'cpu_mhz': 1000} || OS-EXT-SRV-ATTR:host | c4f909eb-56c4-41b2-a0a5-ccef71af8d71 || OS-EXT-SRV-ATTR:hypervisor_hostname | demohost01 || OS-EXT-SRV-ATTR:instance_name | 0e4d3940-d7c7-410f-b3f1-72ffda4d5605 || OS-EXT-STS:fault | {u'message': u'Instance 0e4d3940-d7c7-410f-b3f1-72ffda4d5605 could not be found on hypervisor.', u'code': 94043, u'details': u''} | | OS-EXT-STS:vm_state | error

  1. Log in to the host on which the instance resides.

  2. Navigate to the disk file location mentioned in the ostackhost.log error.

561 TRACE oslo_messaging.rpc.server libvirtError: internal error: qemu unexpectedly closed the monitor: XXXX-XX-XXTXX:XX:XX.084234Z qemu-kvm: -drive file=/mnt/nfs/instances/0e4d3940-d7c7-410f-b3f1-72ffda4d5605/disk,format=qcow2,if=none,id=drive-virtio-disk0,cache=none: Failed to get "write" lock

  1. Create a backup copy of the original disk file in the same directory.

# cp disk disk.bak

  1. Rename the original disk to disk.old.

# mv disk disk.old

  1. Rename the backup disk to disk.

# mv disk.bak disk

  1. Set the instance status to active.

# openstack server set --state active [instance-id]

  1. Stop the server.

# openstack server stop [instance-id]

  1. Start the server.

# openstack instance start [instance-id]


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Instance in ERROR State, Write Lock on Disk FileProblemEnvironmentCauseResolution