How Do You Troubleshoot the Error “intx ThreadPriorityPolicy=42 is outside the allowed range [ 0 … 1 ] “?

Problem scenario
You try to start Cassandra but you get this error:

“[0.000s][warning][gc] -Xloggc is deprecated. Will use -Xlog:gc:./bin/../logs/gc.log instead.
intx ThreadPriorityPolicy=42 is outside the allowed range [ 0 … 1 ]
Improperly specified VM option ‘ThreadPriorityPolicy=42’
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.”

Possible solution #1
Migrate to Linux SUSE or a Red Hat family version of Linux (e.g.,

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How Do You Enter Data into a Cassandra Table?

Problem scenario
You want to insert data into a Cassandra table.  How do you do this?

Solution
Prerequisites

Install and configure Cassandra.  If you do not know how, click on this link and go to “Possible Solution #5” at the bottom to determine the distribution of Linux that you have.

Procedures
1.  Create the table with this command:
CREATE TABLE contint(
  

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How Do You Install the Elastic Stack on Any Type of Linux?

Updated on 9/24/19

Problem scenario
You want to install Elastic Stack on different distributions of Linux with the same exact script.  What should you do?

Solution
Prerequisites
i. You should have at least 3 GB of total memory (a combination of virtual memory and RAM) allocated to the server. If you need to add memory,

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How Do You Get hdfs or Yarn to Start When You Get an Error Such As “Permission denied (publickey,gssapi-keyex,gssapi-with-mic)”?

Problem scenario
You try to use start-dfs.sh or start-yarn.sh.  You received this message:  Permission denied (publickey,gssapi-keyex,gssapi-with-mic).

What do you do?

Solution
You need to be able to ssh into the node without any Hadoop components.  To help you troubleshoot, consider the following items on the server that is causing the problem (e.g., the DataNode server, but it could be the NameNode server itself):

1. 

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How Do You Troubleshoot the Message “/usr/bin/mongodb/bin/mongod: error while loading shared libraries: libcrypto.so.1.0.0: cannot open shared object file: No such file or directory”?

Problem scenario
You are using a Red Hat derivative of Linux (e.g., CentOS/RHEL/Fedora).  When trying to run a mongod command you receive this message: “/usr/bin/mongodb/bin/mongod: error while loading shared libraries: libcrypto.so.1.0.0: cannot open shared object file: No such file or directory”.

What should you do?

Solution
Get different installation media.  If you try to install a .tgz file for Ubuntu on CentOS/RHEL/Fedora, you will get this message. 

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How Do You Get hdfs or Yarn to Start the Jps Process You Expect to Start?

Problem scenario
You use start-dfs.sh and start-yarn.sh and there are no errors.  They seem to work, but when you use the jps command, you do not see the service you expect.  Why isn’t a jps process starting when you run one of these scripts?

Solution
The root cause could be a variety of root causes.  Here are some potential solutions.

1.  In these files,

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How Do You Troubleshoot the Message “error while loading shared libraries: libssl.so.1.0.0: cannot open shared object file: No such file or directory”?

Problem scenario
You are using a Red Hat derivative of Linux (e.g., CentOS/RHEL/Fedora).  When trying to run a mongod command you receive this message: “error while loading shared libraries: libssl.so.1.0.0: cannot open shared object file: No such file or directory”

What should you do?

Solution
Get different installation media.  If you try to install a .tgz file for Ubuntu on CentOS/RHEL/Fedora, you will get this message. 

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How Do You Install MongoDB on a Linux Server?

Problem scenario
You want to install MongoDB on a Linux server.  How do you do this?

Solution
1.  If you know your distribution of Linux, go to step #2.  Otherwise try this command:  cat /etc/*-release

2.  Do one of the following that corresponds to your distribution of Linux:

On Debian:  sudo apt-get -y install mongodb mongodb-server

On Ubuntu 16.x or Ubuntu 17.x run these two commands (that may span three lines):

curl http://repo.mongodb.org/apt/ubuntu/dists/xenial/mongodb-org/3.6/multiverse/binary-amd64/mongodb-org-server_3.6.4_amd64.deb >

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How Do You Troubleshoot the Cassandra Problem about “Connection refused”?

Problem Scenario
You have installed Apache Cassandra on Linux.  It is deployed as a single node configuration (not a cluster).  When you run “cqlsh” you get this error:

“Connection error: (‘Unable to connect to any servers’, {‘127.0.0.1’: error(111, “Tried connecting to [(‘127.0.0.1’, 9042)]. Last error: Connection refused”)})”

How do you troubleshoot cqlsh when you get this message “”Tried connecting to [(‘127.0.0.1’, 9042)].

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How Do You Install Zookeeper on Any Type of Linux?

Updated on 5/14/20

Problem scenario
You want to install Apache Zookeeper with a script.  You want the same script to work regardless of what distribution of Linux you are using (e.g., Ubuntu/Debian, RedHat (including CentOS/Fedora), or SUSE).  How do you write a script to install the latest version of Zookeeper?

Solution
The file that is attached called zki.txt is not needed but is attached as a reference copy of the below. 

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