People may have little bit of confusion about Host Aggregates and Availabaility Zones in Nova. Here I am trying to explain how these things are worked together. All configuration options aer based on Icehouse release of Openstack.
A host aggregate is a grouping of hosts with associated metadata. A host can be in more than one host aggregate. The concept of host aggregates is only exposed to cloud administrators. A host aggregate may be visible to users in the form of an availability
zone. When you create a host aggregate, you have the option of providing
an availability zone name.
The following will create a Availability zone called Ezone-IND with a Name of enterprise.
[root@controller ~]# nova aggregate-create enterprise Ezone-IND
+----+------------+-------------------+-------+-------------------------------+
| Id | Name | Availability Zone | Hosts | Metadata |
+----+------------+-------------------+-------+-------------------------------+
| 3 | enterprise | Ezone-IND | | 'availability_zone=Ezone-IND' |
+----+------------+-------------------+-------+-------------------------------+
List the available hypervisor list to add under this zone.
[root@controller ~]# nova hypervisor-list
+----+----------------------+
| ID | Hypervisor hostname |
+----+----------------------+
| 1 | compute |
| 4 | domain-c15(Cluster1) |
| 5 | compute1 |
+----+----------------------+
Now, we are going to add hypervisor "compute1" under Ezone-IND
[root@controller ~]# nova aggregate-add-host 3 compute1
Host compute1 has been successfully added for aggregate 3
+----+------------+-------------------+------------+-------------------------------+
| Id | Name | Availability Zone | Hosts | Metadata |
+----+------------+-------------------+------------+-------------------------------+
| 3 | enterprise | Ezone-IND | 'compute1' | 'availability_zone=Ezone-IND' |
+----+------------+-------------------+------------+-------------------------------+
Now you can see the Host Compute1 is under Ezone-IND.