Typical Scenario: Collecting Local Dynamic Logs and Uploading Them to HDFS

Scenario

This section describes how to use the Flume server to collect dynamic logs from a local host and save them to the /flume/test directory on HDFS.

This section applies to MRS 3.x or later.

By default, the cluster network environment is secure and the SSL authentication is not enabled during the data transmission process. For details about how to use the encryption mode, see Configuring the Encrypted Transmission. The configuration applies to scenarios where only the Flume is configured, for example, Taildir Source+Memory Channel+HDFS Sink.

Prerequisites

• The cluster has been installed, including the HDFS and Flume services.
• The network environment of the cluster is secure.
• You have created user flume_hdfs and authorized the HDFS directory and data to be operated during log verification.

Procedure

1. On FusionInsight Manager, choose System > User and choose More > Download Authentication Credential to download the Kerberos certificate file of user flume_hdfs and save it to the local host.
   Figure 1 Downloading the authentication credential
   

2. Set Flume parameters.
   Use the Flume configuration tool on FusionInsight Manager to configure the Flume role server parameters and generate a configuration file.

   1. Log in to FusionInsight Manager and choose Cluster > Services. On the page that is displayed, choose Flume. On the displayed page, click the Configuration Tool tab.
      Figure 2 Choosing Configuration Tool
      
   2. Set Agent Name to client. Select the source, channel, and sink to be used, drag them to the GUI on the right, and connect them.

      Use Taildir Source, Memory Channel, and HDFS Sink.

      Figure 3 Example for the Flume configuration tool
      
   3. Double-click the source, channel, and sink. Set corresponding configuration parameters by referring to Table 1 based on the actual environment.
      

      • If you want to continue using the properties.propretites file by modifying it, log in to FusionInsight Manager, choose Cluster > Name of the desired cluster > Services. On the page that is displayed, choose Flume. On the displayed page, click the Configuration Tool tab, click Import, import the file, and modify the configuration items related to non-encrypted transmission.
      • It is recommended that the numbers of Sources, Channels, and Sinks do not exceed 40 during configuration file import. Otherwise, the response time may be very long.

      Table 1 Parameters to be modified for the Flume role server

      Parameter	Description	Example Value
      Name	The value must be unique and cannot be left blank.	test
      filegroups	Specifies the file group list name. This parameter cannot be left blank. The value contains the following two parts: Name: name of the file group list. filegroups: absolute path of dynamic log files.	-
      positionFile	Specifies the location where the collected file information (file name and location from which the file collected) is saved. This parameter cannot be left blank. The file does not need to be created manually, but the Flume running user needs to have the write permission on its upper-level directory.	/home/omm/flume/positionfile
      batchSize	Specifies the number of events that Flume sends in a batch.	61200
      hdfs.path	Specifies the HDFS data write directory. This parameter cannot be left blank.	hdfs://hacluster/flume/test
      hdfs.filePrefix	Specifies the file name prefix after data is written to HDFS.	TMP_
      hdfs.batchSize	Specifies the maximum number of events that can be written to HDFS once.	61200
      hdfs.kerberosPrincipal	Specifies the Kerberos authentication user, which is mandatory in security versions. This configuration is required only in security clusters.	flume_hdfs
      hdfs.kerberosKeytab	Specifies the keytab file path for Kerberos authentication, which is mandatory in security versions. This configuration is required only in security clusters.	/opt/test/conf/user.keytab NOTE: Obtain the user.keytab file from the Kerberos certificate file of the user flume_hdfs. In addition, ensure that the user who installs and runs the Flume client has the read and write permissions on the user.keytab file.
      hdfs.useLocalTimeStamp	Specifies whether to use the local time. Possible values are true and false.	true

   4. Click Export to save the properties.properties configuration file to the local.

3. Upload the configuration file.

   Upload the file exported in 2.d to the flume/conf directory of the cluster. For details, see 2.b.

4. Verify log transmission.
   1. Log in to FusionInsight Manager as a user who has the management permission on HDFS. For details, see Accessing FusionInsight Manager (MRS 3.x or Later). Choose Cluster > Services > HDFS. On the page that is displayed, click the NameNode(Node name,Active) link next to NameNode WebUI to go to the HDFS web UI. On the displayed page, choose Utilities > Browse the file system.
   2. Check whether the data is generated in the /flume/test directory on the HDFS.
      Figure 4 Checking HDFS directories and files