Preparing for Development and Operating Environment

Preparing Development Environment

Table 1 describes the environment required for application development.

**Table 1** Development environment
Item	Description
OS	Development environment: Windows OS. Windows 7 or later is supported. Operating environment: Linux OS. If the program needs to be commissioned locally, the running environment must be able to communicate with the cluster service plane network.
JDK installation	Basic configuration for the development and operating environment. The version requirements are as follows: The server and client support only built-in OpenJDK, version: 1.8.0_272, and therefore a JDK replacement is not allowed. Customers' applications that need to reference the JAR packages of SDK to run in the application processes support Oracle JDK, IBM JDK, and OpenJDK. For x86 nodes that run clients, the following JDKs can be used: Oracle JDK versions: 1.8 IBM JDK versions: 1.8.5.11 For nodes that run TaiShan and clients, the following JDK can be used: OpenJDK: 1.8.0_272
IntelliJ IDEA installation and configuration	IntelliJ IDEA is a tool used to develop Flink applications. The version must be 2019.1 or other compatible version.
Scala installation	Install Scala is the basic configuration for the Scala development environment. The required version is 2.11.7.
Scala plug-in installation	Installing Scala plug-ins is the basic configuration for the Scala development environment. The required version is 1.5.4.
Maven installation	Basic configuration of the development environment for project management throughout the lifecycle of software development.
Developer account preparation	See Preparing a Developer Account for configuration.
7-zip	It is a tool used to decompress .zip and .rar packages. The 7-Zip 16.04 is supported.

Preparing an Operating Environment

During application development, you need to prepare the code running and commissioning environment to verify that the application is running properly.

If you use the Linux environment for commissioning, you need to prepare the Linux node where the cluster client is to be installed and obtain related configuration files.

Install the client on the node. For example, the client installation directory is /opt/client.
Ensure that the difference between the client time and the cluster time is less than 5 minutes.

For details about how to use the client on a Master or Core node in the cluster, see Using an MRS Client on Nodes Inside a Cluster. For details about how to install the client outside the MRS cluster, see Using an MRS Client on Nodes Outside a Cluster.
- Verify that the configuration options in the Flink client configuration file flink-conf.yaml are correctly configured. For details, see Preparing for Security Authentication.
- In security mode, appended the service IP address of the node where the client is installed and floating IP address of Manager to the jobmanager.web.allow-access-address configuration item in the flink-conf.yaml file. Use commas (,) to separate IP addresses.

Log in to the FusionInsight Manager portal. Download the cluster client software package to the active management node and decompress it. Then, log in to the active management node as user root. Go to the decompression path of the cluster client and copy all configuration files in the FusionInsight_Cluster_1_Services_ClientConfig\Flink\config directory to the conf directory where the compiled JAR package is stored for subsequent commissioning, for example, /opt/client/conf.

For example, if the client software package is FusionInsight_Cluster_1_Services_Client.tar and the download path is /tmp/FusionInsight-Client on the active management node, run the following command:

cd /tmp/FusionInsight-Client

tar -xvf FusionInsight_Cluster_1_Services_Client.tar

tar -xvf FusionInsight_Cluster_1_Services_ClientConfig.tar

cd FusionInsight_Cluster_1_Services_ClientConfig

scp Flink/config/* root@IP address of the client node:/opt/client/conf

The keytab file obtained during the Preparing a Developer Account is also stored in this directory. Table 2 describes the main configuration files.

**Table 2** Configuration file
Document Name	Function
core-site.xml	Configures Flink parameters.
hdfs-site.xml	Configures hdfs parameters.
yarn-site.xml	Configures yarn parameters.
flink-conf.yaml	Configures Flink parameters.
user.keytab	Provides user information for Kerberos security authentication.
krb5.conf	Kerberos server configuration information

Check the network connection of the client node.
During the client installation, the system automatically configures the hosts file on the client node. You are advised to check whether the /etc/hosts file contains the host names of the nodes in the cluster. If no, manually copy the content in the hosts file in the decompression directory to the hosts file on the node where the client resides, to ensure that the local host can communicate with each host in the cluster.