A Technical I.T./DevOps Blog
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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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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Continue reading “How Do You Run a Groovy Program on a Red Hat Derivative Linux Server?”
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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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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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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Continue reading “How Do You Install kubectl on Any Type of Linux?”
Problem scenario
You run “sudo salt-minion -l debug” on a Salt Minion. You see this message: “[INFO ] SaltReqTimeoutError: after 60 seconds. (Try 4 of 7)”
What should you do?
Solution
Go to the Salt Master server. Run this command: sudo systemctl start salt-master
Problem scenario
You have a Red Hat distribution of Linux (e.g., CentOS/RHEL/Fedora). How do you install SonarQube?
Solution
Prerequisites
Install the Java Development Kit so you can later take advantage of plugins. If you need assistance with this, see this link.
Procedures
For future reference, at some point the “9.6”s you see below will have to be incremented to a newer version of PostgreSQL.
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Continue reading “How Do You Install SonarQube on a Red Hat Distribution of Linux?”
Problem scenario
A “git clone git@…” command prompts the user for a password. What is the password or how is it set?
Solution
The authentication for such a git command is usually done by the individual servers not through Git itself. You should go to the server with the source repository, and run this to change the password to something you know:
sudo passwd git
Alternatively you could change the owner and group of the .git file or the permissions of the git file.
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Problem scenario
You are trying to debug a Python program that uses shell (or Bash) commands. The shell or Bash commands work when they are called with Python’s subprocess.check_output. They do not work when called directly from the Linux command prompt. What is wrong?
Possible solutions
Normally I.T. professionals can get the Linux (Bash or shell) commands to work without as many moving parts. In some instances the Python script that executes the Bash commands seem to help the reliability of the commands.
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Problem scenario
You want to use a Java Virtual Machine language on an Ubuntu Linux server. You want to test out the language too. What should you do?
Prerequisites
Install Groovy version 1; this command should work: sudo apt-get -y update; sudo apt-get -y install groovy
Procedures
1. Create a file called hello.groovy with the following five lines:
class Example {
static void main(String[] args) {
println(‘Hello World’); …
Continue reading “How Do You Run a Groovy Program on a Debian or Ubuntu Server?”