We still have references to old (already decommissioned) hardware somewhere in the database, as the prometheus-openstack-exporter reports data for them.
Example:
```lang=shell-session
aborrero@cloudcontrol1007:~$ curl localhost:12345/metrics -o metrics.prom
aborrero@cloudcontrol1007:~$ grep cloudvirt1001 metrics.prom
openstack_placement_resource_allocation_ratio{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="DISK_GB"} 1.5
openstack_placement_resource_allocation_ratio{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="MEMORY_MB"} 1
openstack_placement_resource_allocation_ratio{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="VCPU"} 4
openstack_placement_resource_reserved{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="DISK_GB"} 0
openstack_placement_resource_reserved{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="MEMORY_MB"} 512
openstack_placement_resource_reserved{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="VCPU"} 0
openstack_placement_resource_total{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="DISK_GB"} 2015
openstack_placement_resource_total{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="MEMORY_MB"} 386952
openstack_placement_resource_total{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="VCPU"} 48
openstack_placement_resource_usage{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="DISK_GB"} 52
openstack_placement_resource_usage{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="MEMORY_MB"} 2048
openstack_placement_resource_usage{hostname="cloudvirt1001.eqiad.wmnet",resourcetype="VCPU"} 4
```
This is likely somewhere in the placement database, but I couldn't find where:
```lang=shell-session
aborrero@cloudcontrol1007:~$ sudo mysql -u root
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| cinder |
| designate |
| eqiad1_ceph_backy |
| eqiad1_heat |
| eqiad1_magnum |
| glance |
| information_schema |
| keystone |
| mysql |
| neutron |
| nova_api_eqiad1 |
| nova_cell0_eqiad1 |
| nova_eqiad1 |
| performance_schema |
| placement |
| trove_eqiad1 |
+--------------------+
16 rows in set (0.001 sec)
MariaDB [(none)]> use placement;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
MariaDB [placement]> show tables;
+------------------------------+
| Tables_in_placement |
+------------------------------+
| alembic_version |
| allocations |
| consumer_types |
| consumers |
| inventories |
| placement_aggregates |
| projects |
| resource_classes |
| resource_provider_aggregates |
| resource_provider_traits |
| resource_providers |
| traits |
| users |
+------------------------------+
13 rows in set (0.000 sec)
```
However, at least some parts of openstack knows that these hosts don't exists:
```lang=shell-session
aborrero@cloudcontrol1007:~$ sudo wmcs-openstack hypervisor list | grep cloudvirt1001
[.. nothing ..]
```