The Updates and Extensions panel provides a list of available files that can be downloaded and installed. This view is also only available to UserIDs with the admin role.

Note

Administrators should be cautious to ensure that Horizon Extensions they install come from a trusted source and/or have undergone appropriate review and testing. Administrators should be aware of the risk of spear phishing, by which they may receive an offer to install an apparently useful application which also performs malicious actions.

Host aggregates are a grouping of physical servers or hosts with associated metadata. A host can belong to multiple aggregates.

Common use cases for host aggregates include supporting the scheduling of instances to a subset of hosts that have a specific capability or flavor such as a specific type of storage, lots of RAM, and/or large numbers of processors.

Another use case of host aggregates is to support the arrangement of hosts into logical groups for load balancing and instance distribution. Host aggregates are configured and only viewable by system admins. The end user view of a host aggregate is called an Availability Zone. Availability zones are created via the Nova API and the host aggregates function. End users can use availability zones for similar use cases. For example, an application could be deployed on hosts in multiple availability zones. A load balancer can then be configured and the instances running each deployment of the application in each availability zone can be assigned to the load balancer thus providing a measure of failover and high availability support.

Additional information on host aggregates and availability zones is available at http://blog.russellbryant.net/2013/05/21/availability-zones-and-host-aggregates-in-openstack-compute-nova/ and http://docs.openstack.org/openstack-ops/content/scaling.html.

The Instances panel provides a view of all deployed end user instances across all projects, the images applied to those instances, the status of each instance, flavor type, and network information. This information is also supplied by the Nova API.

The Volumes panel is displayed if the OpenStack Cinder service is available. Cinder provides block storage infrastructure. Block storage provides the ability for end users to attach storage as discrete drives to a compute instance. These drives are persistent and can be reassigned to a different instance. The Volumes tab on this view shows all currently created volumes and associated metadata and status, which physical host the volume is hosted on, and the ability for the admin to manage each volume.

Flavors are virtual hardware templates. Flavors are used to define a virtual compute host. Flavors are assigned during the creation of a new instance. This panel displays all of the current flavor types and provides the ability for the admin to create, edit or delete flavors. Hosting organizations often use flavors as a form of billing unit; flavors with more resources are charged at a higher rate than flavors with fewer resources.

Images are discrete software builds that can be loaded onto an instance. An image can be a standalone operating system implementation or a bundle of operating system and other pre-configured applications. This panel displays all currently available images and associated metadata and enables the system administrator to create, edit and delete images.

Important

If you encounter the following error:

ERROR: Unable to create new image. URL scheme not supported.

The error message indicates that the Glance service has not been configured to support the import of Glance images via the http option. This option can be enabled by your system administrator by enabling this function in the Glance configuration file.

Networks are used by end users to provide connectivity to and between their deployed instances. This panel provides a list of all currently deployed networks and associated metadata and enables the system administrator the ability to created, edit, and delete networks.

Quotas provide the means to limit resource usage. Quotas are assigned per project. This panel provides a view of all current quotas and enables a system administrator with the ability to edit quota line items.

The Identity panel has two major panels. The Projects panel provides a list of all current projects and enables a system administrator the ability to create, modify, and delete panels and panel membership.

The Users panel is available only to system administrators and provides the ability to create, modify, and delete users. These users are considered "local" to Keystone and are authenticated by Keystone.