6.4.5. Additional Region and Zone Tasks

List all available regions with the following command:

# oo-admin-ctl-region -c list

Remove region and zone tags from a node with the following command:

# oo-admin-ctl-district -c unset-region -n district_name -i server_identity

Remove zones from a region with the following command:

# oo-admin-ctl-region -c remove-zone -r region_name -z zone_name

Destroy empty regions with the following command:

# oo-admin-ctl-region -c destroy -r region_name

Procedure 6.10. To Require New Applications Use Zones:

In the /etc/openshift/plugins.d/openshift-origin-msg-broker-mcollective.conf file on the broker host, set the ZONES_REQUIRE_FOR_APP_CREATE parameter to true to require that new applications only use nodes tagged with a zone. When true, gear placement will fail if there are no zones available with the correct gear profile:
```
ZONES_REQUIRE_FOR_APP_CREATE=true
```
Restart the broker service:
```
# service openshift-broker restart
```

Procedure 6.11. To Enforce the Minimum Number of Zones per Gear Group

In the /etc/openshift/plugins.d/openshift-origin-msg-broker-mcollective.conf file on the broker host, set the ZONES_MIN_PER_GEAR_GROUP parameter to the desired minimum number of zones between which gears in application gear groups are distributed:
```
ZONES_MIN_PER_GEAR_GROUP=number_of_zones
```
Restart the broker service:
```
# service openshift-broker restart
```