No Valid Host From Host Aggregates Resulted in Instance Spawning Failure

Problem

  • Cold Migration for the instance failed as it could not find any valid host for the instance to be deployed on.

  • It queried the hosts available within host aggregates, however, since the flavor used for the instance did not match with any of the host aggregate metadata, migration failed.

# less nova-scheduler.log | grep [UUID]
INFO nova.filters [req-XYZ [UUID] [PROJECTUUID] - - -] Filtering removed all hosts for the request with instance ID '[UUID]'. Filter results: ['RetryFilter: (start: 8, end: 8)', 'AggregateMultiTenancyIsolation: (start: 8, end: 6)', 'AvailabilityZoneFilter: (start: 6, end: 6)', 'ServerGroupAffinityFilter: (start: 6, end: 6)', 'ServerGroupAntiAffinityFilter: (start: 6, end: 6)', 'AggregateInstanceExtraSpecsFilter: (start: 6, end: 0)']
# openstack server show [UUID] --fit-width
+-------------------------------------+------------------------------------------------------
|Field | Value
+-------------------------------------+------------------------------------------------------
| OS-DCF:diskConfig | MANUAL
| OS-EXT-AZ:availability_zone | nova
| OS-EXT-PF9-SRV-RES-INFO:res_info | {u'cfg_disk_gb': 150.0, u'vcpus': 4, u'cfg_memory_mb': 65536, u'cpu_mhz': 1000} |
| OS-EXT-SRV-ATTR:host | [HOST]
| OS-EXT-SRV-ATTR:hypervisor_hostname | [HOSTNAME]
| OS-EXT-SRV-ATTR:instance_name | [INSTANCE_NAME]
| OS-EXT-STS:fault | {u'message': u'No valid host was found. \n6 hosts failed with error: Can not find a host aggregate | matching instance extra spec requirement', u'code': 500, u'details': u' File

Environment

  • Platform9 Managed OpenStack - All Versions

Cause

Host aggregate to match the instance flavor specifications is not present.

# openstack flavor show SampleFlavor
+----------------------------+-----------------------+
| Field | Value |
+----------------------------+-----------------------+
| OS-FLV-DISABLED:disabled | False |
| OS-FLV-EXT-DATA:ephemeral | 0 |
| access_project_ids | None |
| disk | 80 |
| id | 6 |
| name | SampleFlavor |
| os-flavor-access:is_public | True |
| properties | host='AggregateMatch' |
| ram | 8192 |
| rxtx_factor | 1.0 |
| swap | |
| vcpus | 4 |
# openstack aggregate list | grep sampleagg

Resolution

  1. Create a host aggregate matching the Instance flavor specifications.

$ openstack aggregate create sampleagg
$ openstack aggregate set --property host='AggregateMatch'
$ openstack aggregate add host 1 [HOST ID]

  1. If the flavor properties is not set, it is mandatory to specify one or more key-value pairs that match the key-value pairs on the host aggregates with the scope aggregate_instance_extra_specs. For our case, it is the aggregate_instance_extra_specs: host='AggregateMatch' key-value pair.

  2. Set the key-value pair using the following command.

$ openstack flavor set SampleFlavor --property host='AggregateMatch'

Additional Information

OpenStack Host Aggregate Document

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