Host aggregates enable administrative users to assign key-value pairs
to groups of machines.

Each node can have multiple aggregates and each aggregate can have
multiple key-value pairs. You can assign the same key-value pair to
multiple aggregates.

The scheduler uses this information to make scheduling decisions. For
information, see Scheduling.

To create a host aggregate

1. Log in to the Dashboard and select the admin project from the
   drop-down list.

2. On the Admin tab, open the Compute tab and click
   the Host Aggregates category.

3. Click Create Host Aggregate.

4. In the Create Host Aggregate dialog box, enter or select
   the following values on the Host Aggregate Information tab:

   • Name: The host
     aggregate name.
   • Availability Zone: The cloud provider defines the
     default availability zone, such as us-west,
     apac-south, or nova. You can target the host
     aggregate, as follows:
     • When the host aggregate is exposed as an availability zone, select
       the availability zone when you launch an instance.
     • When the host aggregate is not exposed as an availability zone,
       select a flavor and its extra specs to target the host aggregate.

5. Assign hosts to the aggregate using the Manage Hosts within
Aggregate tab in the same dialog box.

   To assign a host to the aggregate, click + for the
   host. The host moves from the All available hosts list to the Selected hosts
   list.

You can add one host to one or more aggregates. To add a host to an
existing aggregate, edit the aggregate.

To manage host aggregates

1. Select the admin project from the drop-down list at the top
   of the page.
2. On the Admin
   tab, open the Compute tab and click the Host Aggregates
   category.

   • To edit host aggregates, select the host aggregate that you want
     to edit. Click Edit Host Aggregate.

     In the Edit Host Aggregate dialog box, you can change
     the name and availability zone for the aggregate.

   • To manage hosts, locate the host aggregate that you want to edit
     in the table. Click More and select Manage Hosts.

     In the Add/Remove Hosts to Aggregate dialog box, click
     + to assign a host to an aggregate. Click
     – to remove a host that is assigned to an
     aggregate.

   • To delete host aggregates, locate the host aggregate that you
     want to edit in the table. Click More and select Delete Host Aggregate.