+++
title = "Azure Event Hubs"
availability = "v1.0+"
maintainer = "Microsoft"
description = "Scale applications based on Azure Event Hubs."
notice = "As of now, the Event Hub scaler only supports reading checkpoints from Blob Storage, as well as scaling only Event Hub applications written in C#, Java, Python or created with Azure Functions."
go_file = "azure_eventhub_scaler"
+++

### Trigger Specification

This specification describes the `azure-eventhub` trigger for Azure Event Hubs.

```yaml
triggers:
- type: azure-eventhub
  metadata:
    connection: EVENTHUB_CONNECTIONSTRING_ENV_NAME # Connection string for Event Hub namespace appended with "EntityPath=<event_hub_name>"
    storageConnection: STORAGE_CONNECTIONSTRING_ENV_NAME # Connection string for account used to store checkpoint. As of now the Event Hub scaler only reads from Azure Blob Storage.
    consumerGroup: $Default # Optional. Consumer group of event hub consumer. Default: $Default
    unprocessedEventThreshold: '64' # Optional. Target number of unprocessed events across all partitions in Event Hub for HPA. Default: 64 events.
    blobContainer: 'name_of_container' # Optional. Container name to store checkpoint. This is needed when a using an Event Hub application written in dotnet or java, and not an Azure function.
```

The `connection` value is the name of the environment variable your deployment uses to get the Event Hub connection string which is appended with the Event Hub name using Entity Path variable. `storageConnection` is the name of the environment variable your deployment uses to get the Storage connection string.

Environment variables are usually resolved from a `Secret V1` or a `ConfigMap V1` collections. `env` and `envFrom` are both supported.

### Authentication Parameters

Not supported yet.

### Example

```yaml
apiVersion: keda.k8s.io/v1alpha1
kind: ScaledObject
metadata:
  name: azure-eventhub-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    deploymentName: azureeventhub-function
  triggers:
  - type: azure-eventhub
    metadata:
      # Required
      connection: EventHub
      storageConnection: AzureWebJobsStorage
      # Optional
      consumerGroup: $Default # default: $Default
      unprocessedEventThreshold: '64' # default 64 events.
      blobContainer: ehcontainer
```