OpenStack Horizon is the web-based graphical user interface (GUI) for managing and orchestrating OpenStack cloud resources. It provides a dashboard that allows users to interact with various OpenStack services such as Nova (compute), Neutron (networking), Cinder (block storage), Glance (image service), and more.
Horizon is designed to be extensible, allowing developers to add custom functionality and integrate additional services into the dashboard. One way to extend Horizon is by using Horizon plugins. The Horizon plugin registry is a mechanism that enables the discovery, registration, and integration of custom plugins into the Horizon dashboard.
Here are the key aspects of the OpenStack Horizon plugin registry:
- Plugin Discovery: Horizon plugins are discovered by the Horizon dashboard through a designated entry point in the Python package. Plugins are packaged as Python packages and can be distributed separately from the core Horizon codebase. The plugin discovery mechanism allows the dashboard to find and load the plugins dynamically.
- Plugin Registration: Once a plugin is discovered, it needs to be registered with the Horizon plugin registry. Registration involves providing metadata about the plugin, such as its name, description, version, and any dependencies it may have. This information is used by Horizon to display the plugin in the dashboard’s user interface and manage its lifecycle.
- Dashboard Integration: Registered plugins can extend the Horizon dashboard by adding new panels, forms, tables, workflows, and other UI components. These components can be integrated into existing dashboard sections or create entirely new sections within the interface. Plugins can also contribute to the navigation menu, providing easy access to their functionality.
- Service Integration: Horizon plugins can integrate with OpenStack services by leveraging the corresponding Python SDKs or APIs. This allows the plugin to interact with the underlying services and perform actions such as creating instances, managing networks, or provisioning storage. Plugins can also provide custom views or workflows to simplify the user experience for specific service operations.
- Policy Enforcement: Horizon provides a policy framework that controls access to various resources and actions within the dashboard. Plugins can define their own policies, ensuring that only authorized users can access their functionality. By utilizing the policy enforcement mechanisms, plugins can integrate with the overall security model of OpenStack.
- Plugin Updates and Maintenance: The plugin registry enables plugin developers to distribute updates and bug fixes independently of the core Horizon codebase. Users can install, upgrade, or remove plugins without modifying the Horizon source code. This modular approach allows for easier maintenance and reduces the risk of introducing breaking changes.
Overall, the Horizon plugin registry is a flexible and extensible mechanism that empowers developers to enhance the functionality and user experience of the Horizon dashboard. It promotes customization and integration with additional services, enabling users to tailor their OpenStack deployment to their specific needs.