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7.5.0 Development
This section contains information related to application development for Ezmeral ecosystem components and HPE Ezmeral Data Fabric products, including the file system, Database (Key-Value and JSON), and Event Streams.
File Store and Apps
The following sections provide information about accessing the File Store with C and Java applications.
Copying Data from Apache Hadoop to a Data Fabric Cluster
Describes the procedure to copy data from an Apache Hadoop to a Data Fabric cluster.
Copying Data Using NFS for the HPE Ezmeral Data Fabric
Describes how to copy files from one data-fabric cluster to another using NFS for the HPE Ezmeral Data Fabric.

HPE Ezmeral Data Fabric – Customer-Managed 7.5.0 Documentation

7.5.0 Development
This section contains information related to application development for Ezmeral ecosystem components and HPE Ezmeral Data Fabric products, including the file system, Database (Key-Value and JSON), and Event Streams.
- Application Development Process
  Before you start developing applications on the HPE Ezmeral Data Fabric platform, consider how you will get the data into the platform, the storage format of the data, the type of processing or modeling that is required, and how the data will be accessed.
- File Store and Apps
  The following sections provide information about accessing the File Store with C and Java applications.
  - Copying Data from Apache Hadoop to a Data Fabric Cluster
    Describes the procedure to copy data from an Apache Hadoop to a Data Fabric cluster.
    - Copy Data Using the hdfs:// Protocol
      Describes the procedure to copy data from a HDFS cluster to a HPE Ezmeral Data Fabric cluster using the hdfs:// protocol.
    - Copying Data Using the webhdfs:// Protocol
      Describes how to copy data from a HDFS cluster to a HPE Ezmeral Data Fabric cluster using the webhdfs:// protocol.
    - Copying Data Using NFS for the HPE Ezmeral Data Fabric
      Describes how to copy files from one data-fabric cluster to another using NFS for the HPE Ezmeral Data Fabric.
  - Accessing the File System with C Applications
  - Accessing HPE Ezmeral Data Fabric File Store in Java Applications
- HPE Ezmeral Data Fabric Database and Apps
  This section contains information about developing client applications for JSON and key-value tables.
- Apache Kafka Wire Protocol Service
  HPE Ezmeral Data Fabric Streams supports Apache Kafka Wire Protocol Service. Apache Kafka Wire Protocol Service is a TCP/IP service that emulates a Kafka cluster backed by HPE Ezmeral Data Fabric Streams. The service makes it possible for Apache Kafka clients written in any programming language to access topics in HPE Ezmeral Data Fabric Streams.
- HPE Ezmeral Data Fabric Streams and Apps
  HPE Ezmeral Data Fabric Streams brings integrated publish and subscribe messaging to HPE Ezmeral Data Fabric.
- MapReduce and Apps
  This section contains information associated with developing YARN applications.
- Kubernetes Interfaces for Data Fabric
  This section describes how to leverage the capabilities of the Kubernetes Interfaces for Data Fabric.
- Ecosystem Components
  The following sections provide information about each open-source project that is supported by the HPE Ezmeral Data Fabric.
- Maven and the HPE Ezmeral Data Fabric
  This section discusses topics associated with Maven and the HPE Ezmeral Data Fabric.
- Developer's Reference
  This section contains in-depth information for the developer.
- API Documentation
  HPE Ezmeral Data Fabric supports public APIs for file system, HPE Ezmeral Data Fabric Database, and HPE Ezmeral Data Fabric Streams. These APIs are available for application-development purposes.

Copying Data Using NFS for the HPE Ezmeral Data Fabric

Describes how to copy files from one data-fabric cluster to another using NFS for the HPE Ezmeral Data Fabric.

If NFS for the HPE Ezmeral Data Fabric is installed on the data-fabric cluster, you can mount the data-fabric cluster to the HDFS cluster and then copy files from one cluster to the other using hadoop distcp. If you do not have NFS for the HPE Ezmeral Data Fabric installed and a mount point configured, see Accessing Data with NFS v3 and Managing the HPE Ezmeral Data Fabric NFS Service.

To perform a copy using distcp via NFS for the HPE Ezmeral Data Fabric, you need the following information:

<MapR NFS Server> - the IP address or hostname of the NFS server in the data-fabric cluster
<maprfs_nfs_mount> - the NFS export mount point configured on the data-fabric cluster; default is /mapr
<hdfs_nfs_mount> - the NFS for the HPE Ezmeral Data Fabric mount point configured on the HDFS cluster
<NameNode> - the IP address or hostname of the NameNode in the HDFS cluster
<NameNode Port> - the port on the NameNode in the HDFS cluster
<HDFS path> - the path to the HDFS directory from which you plan to copy data
<MapR filesystem path> - the path in the data-fabric cluster to which you plan to copy HDFS data

To copy data from HDFS to the data-fabric filesystem using NFS for the HPE Ezmeral Data Fabric, complete the following steps:

Mount HDFS.
Issue the following command to mount the data-fabric cluster to the HDFS NFS for the HPE Ezmeral Data Fabric mount point:
```
mount <Data Fabric NFS Server>:/<maprfs_nfs_mount> /<hdfs_nfs_mount>
```
Example
```
mount 10.10.100.175:/mapr /hdfsmount
```

Copy data.

Issue the following command to copy data from the HDFS cluster to the data-fabric cluster:

hadoop distcp hdfs://<NameNode>:<NameNode Port>/<HDFS path> file:///<hdfs_nfs_mount>/<MapR filesystem path>

Example

hadoop distcp hdfs://nn1:8020/user/sara/file.txt file:///hdfsmount/user/sara

Issue the following command from the data-fabric cluster to verify that the file was copied to the data-fabric cluster:
```
hadoop fs -ls /<MapR filesystem path>
```
Example
```
hadoop fs -ls /user/sara
```

(Topic last modified: 2020-10-15)