Configure Amazon IoT Greengrass stream manager - Amazon IoT Greengrass
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Configure Amazon IoT Greengrass stream manager

On Greengrass core devices, stream manager can store, process, and export IoT device data. Stream manager provides parameters that you use to configure runtime settings. These settings apply to all streams on the Greengrass core device. You can use the Amazon IoT Greengrass console or API to configure stream manager settings when you deploy the component. Changes take effect after the deployment completes.

Stream manager parameters

Stream manager provides the following parameters that you can configure when you deploy the component to your core devices. All parameters are optional.

Storage directory


The absolute path of the local folder used to store streams. This value must start with a forward slash (for example, /data).

You must specify an existing folder, and the system user who runs the stream manager component must have permissions to read and write to this folder. For example, you can run the following commands to create and configure a folder, /var/greengrass/streams, which you specify as the stream manager root folder. These commands allow the default system user, ggc_user, to read and write to this folder.

sudo mkdir /var/greengrass/streams sudo chown ggc_user /var/greengrass/streams sudo chmod 700 /var/greengrass/streams

For information about securing stream data, see Local data security.

Default: /greengrass/v2/work/aws.greengrass.StreamManager

Server port


The local port number used to communicate with stream manager. The default is 8088.

You can specify 0 to use a random available port.

Authenticate client


Indicates whether clients must be authenticated to interact with stream manager. All interaction between clients and stream manager is controlled by the Stream Manager SDK. This parameter determines which clients can call the Stream Manager SDK to work with streams. For more information, see Client authentication.

Valid values are true or false. The default is true (recommended).

  • true. Allows only Greengrass components as clients. Components use internal Amazon IoT Greengrass Core protocols to authenticate with the Stream Manager SDK.

  • false. Allows any process that runs on the Amazon IoT Greengrass Core to be a client. Do not set the value to false unless your business case requires it. For example, use false only if non-component processes on the core device must communicate directly with stream manager.

Maximum bandwidth


The average maximum bandwidth (in kilobits per second) that can be used to export data. The default allows unlimited use of available bandwidth.

Thread pool size


The maximum number of active threads that can be used to export data. The default is 5.

The optimal size depends on your hardware, stream volume, and planned number of export streams. If your export speed is slow, you can adjust this setting to find the optimal size for your hardware and business case. The CPU and memory of your core device hardware are limiting factors. To start, you might try setting this value equal to the number of processor cores on the device.

Be careful not to set a size that's higher than your hardware can support. Each stream consumes hardware resources, so try to limit the number of export streams on constrained devices.

JVM arguments

Parameter name: JVM_ARGS

Custom Java Virtual Machine arguments to pass to stream manager at startup. Multiple arguments should be separated by spaces.

Use this parameter only when you must override the default settings used by the JVM. For example, you might need to increase the default heap size if you plan to export a large number of streams.

Logging level

Parameter name: LOG_LEVEL

The logging level for the component. Choose from the following log levels, listed here in level order:



  • INFO

  • WARN


Default: INFO

Minimum size for multipart upload


The minimum size (in bytes) of a part in a multipart upload to Amazon S3. Stream manager uses this setting and the size of the input file to determine how to batch data in a multipart PUT request. The default and minimum value is 5242880 bytes (5 MB).


Stream manager uses the stream's sizeThresholdForMultipartUploadBytes property to determine whether to export to Amazon S3 as a single or multipart upload. User-defined Greengrass components set this threshold when they create a stream that exports to Amazon S3. The default threshold is 5 MB.

See also