# Ostackhost Fails to Resize, Create and Migrate Instance with Error "ComputeHostNotFound ## Problem The cold migration of an instance fails with the following traceback observed in the **ostackhost** log located at */var/log/pf9* on the source host. {% tabs %} {% tab title="None" %} ```none ERROR nova.compute.manager [req-ID] [instance: UUID] Setting instance vm_state to ERROR: ComputeHostNotFound: Compute host compute-prod-6 could not be found.TRACE nova.compute.manager [instance: UUID] Traceback (most recent call last):TRACE nova.compute.manager [instance: UUID] File "/opt/pf9/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 8176, in _error_out_instance_on_exceptionTRACE nova.compute.manager [instance: UUID] yieldTRACE nova.compute.manager [instance: UUID] File "/opt/pf9/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 3910, in do_confirm_resizeTRACE nova.compute.manager [instance: UUID] migration.source_node)TRACE nova.compute.manager [instance: UUID] File "/opt/pf9/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 4013, in _delete_allocation_after_moveTRACE nova.compute.manager [instance: UUID] cn_uuid = rt.get_node_uuid(nodename)TRACE nova.compute.manager [instance: UUID] File "/opt/pf9/venv/lib/python2.7/site-packages/nova/compute/resource_tracker.py", line 157, in get_node_uuidTRACE nova.compute.manager [instance: UUID] raise exception.ComputeHostNotFound(host=nodename)TRACE nova.compute.manager [instance: UUID] ComputeHostNotFound: Compute host compute-prod-6 could not be found. ``` {% endtab %} {% endtabs %} ## Environment * Platform9 Managed OpenStack - v4.0 and higher * Nova ## Cause * Disk file for an instance is missing which prevents ostackhost from updating its resources. {% tabs %} {% tab title="None" %} ```none 2020-03-18 19:08:04.221 ERROR nova.compute.manager [req-ID] Error updating resources for node compute-prod-6: DiskNotFound: No disk at /opt/pf9/data/instances/90990d99-e350-430a-ae28-3b202bf6056e/disk2020-03-18 19:08:04.221 TRACE nova.compute.manager Traceback (most recent call last):2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/nova/compute/manager.py", line 8000, in _update_available_resource_for_node2020-03-18 19:08:04.221 TRACE nova.compute.manager rt.update_available_resource(context, nodename)2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/nova/compute/resource_tracker.py", line 704, in update_available_resource2020-03-18 19:08:04.221 TRACE nova.compute.manager resources = self.driver.get_available_resource(nodename)2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 6661, in get_available_resource2020-03-18 19:08:04.221 TRACE nova.compute.manager disk_over_committed = self._get_disk_over_committed_size_total()2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 8345, in _get_disk_over_committed_size_total2020-03-18 19:08:04.221 TRACE nova.compute.manager self._destroy(inst)2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__2020-03-18 19:08:04.221 TRACE nova.compute.manager self.force_reraise()2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise2020-03-18 19:08:04.221 TRACE nova.compute.manager six.reraise(self.type_, self.value, self.tb)2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 8267, in _get_disk_over_committed_size_total2020-03-18 19:08:04.221 TRACE nova.compute.manager config, block_device_info)2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 8169, in _get_instance_disk_info_from_config2020-03-18 19:08:04.221 TRACE nova.compute.manager qemu_img_info = disk_api.get_disk_info(path)2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/nova/virt/disk/api.py", line 98, in get_disk_info2020-03-18 19:08:04.221 TRACE nova.compute.manager return images.qemu_img_info(path)2020-03-18 19:08:04.221 TRACE nova.compute.manager File "/opt/pf9/venv/lib/python2.7/site-packages/nova/virt/images.py", line 58, in qemu_img_info2020-03-18 19:08:04.221 TRACE nova.compute.manager raise exception.DiskNotFound(location=path)2020-03-18 19:08:04.221 TRACE nova.compute.manager DiskNotFound: No disk at /opt/pf9/data/instances/90990d99-e350-430a-ae28-3b202bf6056e/disk ``` {% endtab %} {% endtabs %} * This happens if an instance is resized or cold migrated and the confirm resize operation is not performed. ## Resolution 1. Perform a confirm resize operation on the instance by running the following command. {% tabs %} {% tab title="None" %} ```none # openstack server resize --confirm [server UUID] ``` {% endtab %} {% endtabs %} 2. If the instance goes into an error state, navigate to the instance storage path, identify the instance directory, and modify its name using the following command. {% tabs %} {% tab title="None" %} ```none # cd /opt/pf9/data/instances/# mv 90990d99-e350-430a-ae28-3b202bf6056e_resize 90990d99-e350-430a-ae28-3b202bf6056e ``` {% endtab %} {% endtabs %} 3. After renaming the directory, set the instance into an ACTIVE state and perform a stop and start operation on the instance. {% tabs %} {% tab title="None" %} ```none # openstack server set --state active [server_UUID]# openstack server stop [server_UUID]# openstack server start [server_UUID] ``` {% endtab %} {% endtabs %} ## Additional Information Related upstream bug: --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://platform9.com/kb/pmo/solution/ostackhost-fails-to-resize-create-and-migrate-instance-with-err.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. 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