Aodh is the alarm service component of OpenStack, an open-source cloud computing platform. The Aodh API provides a RESTful interface for managing alarms within an OpenStack environment. Alarms are used to monitor and trigger actions based on specific events or conditions in the cloud infrastructure.
Here are some key details about the Aodh API:
- Alarm Types: Aodh supports various types of alarms, including threshold alarms, combination alarms, and event alarms. Threshold alarms monitor a specific metric and trigger when the metric value crosses a predefined threshold. Combination alarms allow you to define complex logical combinations of other alarms. Event alarms react to specific events or notifications emitted by other OpenStack services.
- API Operations: The Aodh API provides operations to manage alarms, such as creating, updating, deleting, and querying alarms. You can create alarms using different parameters like name, description, alarm type, and threshold values. The API also allows you to query and list alarms based on various filters like alarm state, severity, and resource ID.
- Webhooks and Actions: Aodh supports webhooks and actions, which enable you to trigger external actions or notifications when an alarm state changes. Webhooks allow you to send HTTP requests to a specific URL, while actions execute predefined tasks or notifications.
- Alarm State Transitions: Alarms in Aodh can have different states, including “ok,” “alarm,” “insufficient data,” and “unknown.” The state transitions occur based on the evaluation of alarm conditions. For example, when a metric value crosses a threshold, the alarm transitions from “ok” to “alarm.”
- Integration with Ceilometer: Aodh tightly integrates with Ceilometer, the telemetry service component of OpenStack. Ceilometer collects various metrics and data from the cloud infrastructure, which Aodh can use to create alarms. Aodh leverages the collected data to evaluate alarms based on user-defined rules.
- Event and Notification Service: Aodh can subscribe to notifications and events emitted by other OpenStack services. This allows Aodh to react to specific events and trigger alarms accordingly. For example, it can monitor the creation or deletion of instances and raise alarms based on predefined rules.
- Authentication and Access Control: The Aodh API supports OpenStack’s authentication and access control mechanisms. Users need to authenticate using their OpenStack credentials and obtain an authentication token to interact with the Aodh API. Role-based access control (RBAC) policies can be enforced to control user access to alarms and API operations.
It’s worth noting that Aodh is just one component of OpenStack’s telemetry ecosystem. It works together with other services like Ceilometer, Gnocchi, and Panko to provide a comprehensive monitoring and alarming solution for OpenStack deployments.