Preparing the Configuration Files for Connecting to the Cluster

Preparing User Information for Cluster Authentication

For an MRS cluster with Kerberos authentication enabled, prepare a user who has the operation permission on related components for program authentication.

The following Kafka permission configuration example is for reference only. You can modify the configuration as you need.

Log in to FusionInsight Manager.
Choose Cluster > Services > Kafka. On the displayed page, click More > Enable Ranger in the upper right corner. Check whether the button is grayed out.
- If it is grayed out, create a user and assign related operation rights to the user in Ranger.
  1. Choose System > Permission > User. On the displayed page, click Create. On the displayed page, create a machine-machine user, for example, developuser.
    Add the kafkaadmin user group to User Group.
  2. Log in to the Ranger management page as the Ranger administrator rangeradmin.
  3. On the home page, click the component plug-in name in the KAFKA area, for example, Kafka.
  4. Click in the Action column of the row containing the all - topic policy.
  5. In the Allow Conditions area, add an allow condition. Select the user created in 2.a for Select User, and select Select/Deselect All for Permissions.
  6. Click Save.
- If the button is available, create a user and grant related operation permissions to the user on Manager.
  1. Choose User in the navigation pane and click Create on the displayed page. Create a machine-machine user, for example, developuser. Add this user to the kafkaadmin user group.
  2. Click OK.
Log in to FusionInsight Manager as user admin and choose System > Permission > User. In the Operation column of developuser, choose More > Download Authentication Credential. Save the file and decompress it to obtain the user.keytab and krb5.conf files of the user.

Preparing the Configuration Files of the Running Environment

During the development or a test run of the program, you need to use the cluster configuration files to connect to an MRS cluster. The configuration files usually contain the cluster component information file and user files used for security authentication. You can obtain the required information from the created MRS cluster.

Nodes used for program debugging or running must be able to communicate with the nodes within the MRS cluster, and the hosts domain name must be configured.

Scenario 1: Prepare the configuration files required for debugging in the local Windows development environment.

Log in to FusionInsight Manager and choose Cluster > Dashboard > More > Download Client. In the dialog box that is displayed, set Select Client Type to Configuration Files Only and click OK. After the client package is generated, download the package as prompted and decompress it.
For example, if the client configuration file package is FusionInsight_Cluster_1_Services_Client.tar, decompress it to obtain FusionInsight_Cluster_1_Services_ClientConfig_ConfigFiles.tar. Then, continue to decompress this file.

Go to Kafka\config in the directory where the client configuration file is decompressed and obtain the Kafka configuration files listed in Table 1.

**Table 1** Configuration files
File	Function
client.properties	Kafka client configuration information
consumer.properties	Kafka consumer configuration information
kafkaSecurityMode	whether to enable the security mode for Kafka.
producer.properties	Kafka producer configuration information
server.properties	Kafka server configuration information

Copy the hosts file content from the decompression directory to the hosts file of the local PC.
- If you need to debug the application in the local Windows environment, ensure that the local PC can communicate with the hosts listed in the hosts file.
- If your PC cannot communicate with the network plane where the MRS cluster is deployed, you can bind an EIP to access the MRS cluster. For details, see How Do I Access Kafka of the Cluster in Security Mode on Windows Using EIPs?.
- C:\WINDOWS\system32\drivers\etc\hosts is an example directory in a Windows environment for storing the local hosts file.

Scenario 2: Prepare the configuration files required for running the program in a Linux environment.
1. Install the MRS cluster client on the node.
  For example, the client installation directory can be /opt/client.
2. Obtain the configuration files.
  1. Log in to FusionInsight Manager, click More and select Download Client in the upper right corner of Homepage. Set Select Client Type to Configuration Files Only, select Save to Path, and click OK to download the client configuration file to the active OMS node of the cluster.
  2. Log in to the active OMS node as user root, go to the directory where the client configuration file is stored (/tmp/FusionInsight-Client/ by default), decompress the software package, and obtain the configuration files listed in Table 1 from the Kafka/config directory.
    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 OMS node, run the following commands:
    
    cd /tmp/FusionInsight-Client
    
    tar -xvf FusionInsight_Cluster_1_Services_Client.tar
    
    tar -xvf FusionInsight_Cluster_1_Services_ClientConfig_ConfigFiles.tar
    
    cd FusionInsight_Cluster_1_Services_ClientConfig_ConfigFiles
3. 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 of the hosts file in the decompression directory to the hosts file on the node where the client is located, to ensure that the local host can communicate with each host in the cluster.