An Azure Event Hubs instance is the primary resource that you create in Azure to send and receive events. It acts as a highly scalable data streaming platform that can ingest millions of events per second.
Key Components of an Event Hubs Instance
An Event Hubs instance is composed of several interconnected concepts:
Event Hubs Namespace
The top-level container for your Event Hubs resources. A namespace provides a unique DNS name and acts as a scope for your Event Hubs. You can have multiple Event Hubs within a single namespace. It also manages access policies and other configuration settings.
Event Hub
An Event Hub is the entity within a namespace where events are sent and stored. It's designed for high-throughput event ingestion. Each Event Hub can have a defined number of partitions, which are crucial for parallel processing and scalability.
- Throughput: Event Hubs are designed for high-volume event ingestion.
- Retention: Events are stored for a configurable period, allowing consumers to process them at their own pace.
Partitions
Partitions are ordered, immutable sequences of events. An Event Hub is divided into one or more partitions. Events sent to an Event Hub are directed to a specific partition. This partitioning is key to achieving high throughput and enabling parallel consumption of event streams.
- Ordering: Events within a single partition are always ordered.
- Scalability: More partitions allow for greater parallel processing capabilities by consumers.
- Partition Key: When sending events, you can specify a partition key. Events with the same partition key are guaranteed to go to the same partition, ensuring related events are processed together. If no partition key is specified, Event Hubs uses a round-robin distribution.
Consumer Groups
A consumer group is an abstraction over the Event Hub that allows multiple applications or services to independently consume from the Event Hub. Each consumer group maintains its own view of the event stream and its own offset.
- Independent Consumption: Multiple applications can read the same data stream without interfering with each other.
- State Management: Each consumer group tracks its own position (offset) in the event stream.
- Default Consumer Group: Every Event Hub comes with a default consumer group named
$Default.
Offsets
An offset is a unique, 64-bit integer that identifies the position of an event within a partition. When a consumer reads events, it keeps track of the offset it has processed up to. This offset is used to resume reading from where it left off.
Diagrammatic Representation (Conceptual)
Imagine a large pipeline (Event Hubs Namespace) containing several smaller pipes (Event Hubs). Each smaller pipe is further divided into even smaller, independent channels (Partitions). Different groups of workers (Consumer Groups) can pick up items (Events) from these channels, remembering exactly which item they picked up last (Offset).
Use Cases for Event Hubs Instances
Event Hubs instances are ideal for:
- Real-time analytics
- Log aggregation
- Application monitoring
- Stream processing
- IoT data ingestion
Getting Started
To use an Event Hubs instance, you typically:
- Create an Event Hubs Namespace in your Azure subscription.
- Create one or more Event Hubs within that namespace.
- Configure the desired number of partitions for your Event Hubs.
- Create consumer groups as needed for your applications.
- Use an SDK or Event Hubs compatible API to send and receive events.
Understanding these core concepts is fundamental to effectively leveraging the power of Azure Event Hubs for your event-driven architectures.