Values of Parameters Being None in the Flink, Kafka, and Storm Components

Symptom

In the Flink, Kafka, and Storm components of a big data scenario, some parameters cannot be collected and are displayed as None, as shown in Figure 1.

Figure 1 Big data collection

The parameters are:

• log.dir
• num.network.threads
• num.io.threads
• compression.type
• num.partitions

Possible Cause

The devkit user does not have the permission to read the kafka/conf/server.properties file and cannot collect related parameters.

Troubleshooting Procedure

• Solution 1: As the root user, grant the read permission on the kafka/conf/server.properties file to the devkit user.

1. Go to the directory where the Kafka configuration file is stored, for example, /etc/kafka/conf. /etc indicates the Kafka installation directory.

   cd /etc/kafka/conf

2. Modify the permission on the server.properties file.

   chmod 644 server.properties

• Solution 2: Install Kafka in the /etc or /usr/local directory. The tool can read /etc/kafka/conf/server.properties or /usr/local/conf/server.properties and collect parameters through sudo privilege escalation.