What Do You Do when Cassandra Stalls on “Initializing IndexInfo”?

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Problem scenario
When you start Cassandra you see a message such as this:

INFO [main] 2018-02-03 08:45:55,257 ColumnFamilyStore.java:389 – Initializing system.IndexInfo

What should you do?

Possible Solution #1
Try rebooting the server. This could help the problem.

Possible Solution #2
This next one is merely a workaround. It is not a best practice.

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How Do You Use Google’s Cloud Pub/Sub with Python?

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Problem scenario
You want to use a Data Analytics or a Big Data tool that publishes messages and subscribes to listening to messages being published. You know GCP has a Pub/Sub tool. You know it supports synchronous and asynchronous messaging. How do you use it with Python?

Solution

  1. Log into GCP via the web UI.
  2. Go here: https://console.cloud.google.com/cloudpubsub/
  3. Click “Create Topic”.

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

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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?

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

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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”?

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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?

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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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