I find in ceilometer source:

class InstanceDiscovery, function discover_libvirt_polling line 211 in ceilometer/compute/discovery.py (https://github.com/openstack/ceilomet...):

"metadata": {}

I add a manualy test with "metadata": {"key_name":"key_value"}

Then restart openstack-ceilometer-compute

After that, ceilometer resource-show <instance_id> have "user_metadata.key_name": "key_value" in metadata

In that source file, I have seen a notice like this: # NOTE(sileht): Other fields that Ceilometer tracks # where we can't get the value here, but their are # retreived by notification "metadata": {},

I think, in present, ceilometer compute can not get metadata instance

If is it true, I wonder why there are some document guide (ex: https://developer.openstack.org/draft...) but in ocata version still doesn't have

PS: still waiting for someone help about this

Thank you

UPDATE: Problem solved

change #instance_discovery_method = libvirt_metadata to instance_discovery_method = workload_partitioning in ceilometer.conf

then restart ceilometer compute agent

Ceilometer now can collect instance user_metadata.