Administering the Data Access Gateway

The HPE Data Fabric Data Access Gateway is a service that acts as a proxy and gateway for translating requests between lightweight client applications and the HPE Data Fabric cluster. This section describes considerations when upgrading the service, how to modify configuration settings, and how to administer and manage the service.

Installing the Data Access Gateway Service

The HPE Data Fabric Data Access Gateway is installed when you install the HPE Data Fabric Database using the HPE Data Fabric Installer. To manually install the service, see Installing Data Access Gateway. For conceptual information, see Understanding the HPE Data Fabric Data Access Gateway.

Shutting Down and Upgrading the Data Access Gateway Service

When the Data Access Gateway receives a shutdown request, it stops accepting new requests and returns an error to the client. Any in-progress requests are allowed to complete before shutting down the service. This allows you to perform rolling upgrades.

Modifying Configuration Settings for the Data Access Gateway Service

Logging Properties

The HPE Data Fabric Data Access Gateway uses standard Log4J configuration to control its logging. The log4j properties are in the /opt/mapr/data-access-gateway/conf/log4j2.xml file on nodes where you have installed the service. After modifying any properties on a node, restart the service. For details, see Administering the Data Access Gateway Service.

Log data is stored in the /opt/mapr/data-access-gateway/logs/data-access-gateway.log file.

Application Properties

To configure HPE Data Fabric Data Access Gateway properties, modify /opt/mapr/data-access-gateway/conf/properties.cfg on nodes where you have installed the service.

The following table lists the properties you can configure:
auth.token.expiration
Default: 1800 seconds
Description: Expiration time (in seconds) for the authentication token.
grpc.service.max-message-size
Default: 32MB
Description: The maximum message size that the gRPC service accepts. The default is set to 32MB, as this is the default maximum document size for HPE Data Fabric Database JSON tables. This property is available in Data Access Gateway 2.0.202104302209 and later or 3.0.0.0.202104302219 and later.
grpc.service.ojai.query.result-limit
Default: 5000
Description: Limit on the number of documents returned in retrieval requests using the Node.js and Python OJAI clients.
grpc.service.port
Default: 5678
Description: Port number gRPC clients use to connect to the Data Access Gateway. The Node.js and Python OJAI clients are gRPC clients.
grpc.service.ssl.enabled
Default: cluster
Description: Controls whether TLS is enabled for the gRPC Service.

Values: cluster|true|false

If set to cluster:
  • TLS is enabled if your HPE Data Fabric cluster is secure.
  • TLS is disabled if your HPE Data Fabric cluster is not secure.
rest.https.port
Default:8243
Description: Port number used to connect to the Data Access Gateway using HTTPS.
rest.result.limit
Default:5000
Description: Limit the number of documents returned in retrieval requests using the HPE Data Fabric Database JSON REST API.

There is also a configuration file /opt/mapr/data-access-gateway/conf/ojai-config.json for parameters used by Data Access Gateway clients:

  • HPE Data Fabric Database JSON REST API
  • Node.js OJAI
  • Python OJAI
  • C# OJAI
  • Go OJAI
  • Java OJAI Thin Client

A parameter you can modify is the client sort limit:

{
    "ojai": { 
        "mapr": {
            "query": {
                "max-client-sort-limit": 6000
            }
        }
    }
}

To understand why you might want to modify this parameter, see Comparisons and Sorts in OJAI Queries.

After modifying any parameters on a node, restart the service as described in Administering the Data Access Gateway Service.

Warden Configuration

The Warden configuration for the HPE Data Fabric Data Access Gateway is in the /opt/mapr/data-access-gateway/conf/warden.data-access-gateway.conf file on nodes where you have installed the Data Access Gateway. To control the amount of memory allocated to the service, modify the following settings:

service.heapsize.max
Default:3000
Description: Defines the maximum heap size (in MB) for the service.
service.heapsize.min
Default:3000
Description: Defines the minimum heap size (in MB) for the service.

After modifying the warden configuration file on a node, run configure.sh -R, and restart the service:

/opt/mapr/server/configure.sh -R
maprcli node services -nodes <node name> -name data-access-gateway -action restart
NOTE
Starting from version 5.0, DAG includes Apache Kafka Wire Protocol Service. See Configuring Apache Kafka Wire Protocol Service for configuration details.

Administering the Data Access Gateway Service

The HPE Data Fabric Data Access Gateway is a service that you administer in the same manner as other HPE Data Fabric services. The name of the service is data-access-gateway.

To restart the service through the CLI, run the following command:
maprcli node services -nodes <node name> -name data-access-gateway -action restart

For details about other operations you can perform on the service, see Managing Services.