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. Log in to the dashboard. Choose the admin project from the CURRENT PROJECT drop-down list. On the Admin tab, click the Host Aggregates category. Click Create Host Aggregate. In the Create Host Aggregate window, enter or select the following values: Host Aggregate Info 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. Host within Aggregate tab Selected hosts 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 later, edit the aggregate. Log in to the dashboard. Choose the admin project from the CURRENT PROJECT drop-down list. On the Admin tab, 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 window, you can change the name and availability zone for the aggregate. To manage hosts: Select the host aggregate that you want to edit. Click More. In the Add/Remove Hosts to Aggregate window, click + to assign a host to the aggregate. Click - to remove a host that is assigned to an aggregate. To delete host aggregates: Select the host aggregate that you want to edit. Click More. Click the Delete Host Aggregate option.