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How to deal with Entryopy warnings in 0545-Cloudera Manager? I believe many inexperienced people don't know what to do about it. Therefore, this article summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

one

Purpose of document writing

In the process of using CDH cluster, you will sometimes see an alarm about Entropy on the console of Cloudera Manager as follows:

The alarm indicates that the Entropy value of the OS system is too low. Entropy (Entropy) is a physical quantity to describe the degree of disorder of a system. The greater the entropy of a system, the worse the order of the system (that is, the greater the uncertainty). You can refer to http://www.it610.com/article/2708278.htm. To put it simply, there are multiple levels of applications in Hadoop that use Data at rest encryption, and encryption needs to use random numbers. Only when the entropy (Entropy) value of the system is larger can the randomness of the random numbers of the system be ensured. This article Fayson mainly introduces how to increase the value of system entropy (Entropy).

Test environment

1.RedHat7.3

two

OS Entropy (Entropy) value View

Execute the following command on the command line to check the entropy (Entropy) value of the operating system

[root@cdh01 ~] # cat / proc/sys/kernel/random/entropy_avail

As the output of the command above shows the available entropy (Entropy) of the current OS, run the command several times to determine the status of the current system entropy pool. If entropy remains low (500 or less), you need to increase it by installing rng-tools and starting the rngd service.

three

Rngd service installation

1. From the command line, execute the following command to install the rngd service

[root@cdh02 ~] # yum-y install rng-tools

two。 Set service boot self-startup and modify rngd service startup parameters, reload startup service

Systemctl enable rngd

Cp / usr/lib/systemd/system/rngd.service / etc/systemd/system/

Sed-I-e's rngd ExecStart =\ / sbin\ / ExecStart =\ / sbin\ / rngd-f-r\ / dev\ / urandom/' / etc/systemd/system/rngd.service

Systemctl daemon-reload

3. Start the rngd service

4. Verify OS entropy pool

Increase the entropy (Entropy) value of OS by installing the rngd service, which can be achieved under Redhat6 in the following ways

Sudo yum install rng-tools

Sudo echo 'EXTRAOPTIONS= "- r / dev/urandom" > / etc/sysconfig/rngd

Sudo service rngd start

Sudo chkconfig rngd on

After reading the above, have you mastered the method of dealing with Entryopy warnings in 0545-Cloudera Manager? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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