How Do You Cancel the Uninstallation of a Jenkins Plugin?

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Problem scenario
You started the uninstallation of a plugin in Jenkins via the web UI.  The plugin now says “Uninstallation pending” in the web UI.  You changed your mind (or you accidentally initiated the process to remove the plugin by clicking the “Uninstall” button) about removing the plugin.  What do you do to keep the plugin continuously installed in Jenkins?

Solution
Background
When you initiate the uninstallation of a plugin,

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How Do You Use Amazon Aurora to Try It Out?

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Problem scenario
You know that Amazon Aurora is compatible with either PostgreSQL or MySQL.  While RDS supports these database types as well as Oracle and SQL Server, RDS does not offer all of the advantages that Aurora offers.

You have read about the benefits of Aurora a database PaaS or DBaaS.   You want to deploy Amazon Aurora because it has numerous features for high availability, performance, and scalability. 

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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 Add a Linux User to the sudoers Users?

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Problem scenario
You want a given Linux user to be added to the sudoers group.  You want the user to be able to use the “sudo ” command before running other commands.  How do you give the sudo privilege to a given user?

Solution
If you are using Debian or Ubuntu Linux, do this (but replace “cooluser” with the username of your choice):
sudo adduser cooluser sudo

If you are using CentOS/RHEL/Fedora,

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How Do You Troubleshoot the Vagrant Error “default: Waiting for SSH to become available.”?

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Problem scenario
You run “vagrant up” and you see things stop at this stage:  “==default: Waiting for SSH to become available…”

What should you do?

Possible Solutions
1.  Run the command again with ” –debug” at the end.  This provides verbose output.  

2.  You may want to review your Vagrantfile settings.  This page helps with such a review (i.e.,

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How Do You Run a Groovy Program on a Red Hat Derivative Linux Server?

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Problem scenario
You want to use a Java Virtual Machine language on a CentOS/RHEL/Fedora server.  You want to test out the language too.  What should you do?

Prerequisites
Install Groovy; this command should work (assuming your server is configured to work with a yum repository with groovy):  sudo yum -y install groovy
# If your yum repositories do not have Groovy, see this posting.

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How Do You Test a Remote Oracle Database Connection (with Credentials You Were Given) from a Linux Command Prompt?

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Problem scenario
You have no desktop GUI and a limited ability to install new applications other than the Java compiler.  You are not be allowed to install a SQL command line client such as sqlconnect or a utility such as tnsping.  What should you do to test the credentials, server name and port number to ensure they work to allow access to an Oracle database?

Solution
The overview is to use a Java program with the code provided below.

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How Do You Troubleshoot “java.lang.AbstractMethodError: Method oracle/jdbc/driver/OraclePrepreadStatementWrapper.setBinaryStream (IL java/io/InputStream;)V is abstract”?

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Problem scenario
You get an error such as this on a Linux server:

“Caused by: java.lang.AbstractMethodError: Method oracle/jdbc/driver/OraclePrepreadStatementWrapper.setBinaryStream (IL java/io/InputStream;)V is abstract at oracle.jdbc.driver.OraclePreparedStatementWrapper.setBinaryStream (OraclePreparedStatementWrapper.java)”

What should you do?

Possible Solution #1
If you are doing Java coding, have you imported the packages needed for the line of Java code that is throwing this error?

Possible Solution #2
If you are using JBoss,

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How Do You Install kubectl on Any Type of Linux?

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Problem scenario
You want a quick, generic way to install kubectl on any type of Linux.  What should you do?

Solution
Run these commands:

cd /tmp

curl -Lo kubectl https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl && chmod +x kubectl

sudo mv kubectl /usr/local/bin/

Test it by running this command: kubectl version

(If you would prefer to use apt commands, because you are using a Debian/Ubuntu distribution of Linux,

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