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How Do You Troubleshoot Yum Commands Not Working with the Error “Could Not Resolve Host: mirror.centos.org Unknown Error”?

03/14/201708/23/2019 0 Comments

Problem scenario: Yum commands to install packages are not working. When you use “yum install coolpackage” you get an error like this:

‘
http://mirror.centos.org/altarch/7/os/i386/repodata/repomd.xml: [Errno 14] curl#6 – “Could not resolve host: mirror.centos.org; Unknown error”
Trying other mirror.
https://yum.dockerproject.org/repo/main/centos/7/repodata/repomd.xml: [Errno 14] curl#6 – “Could not resolve host: yum.dockerproject.org; Unknown error”
Trying other mirror.

…
One of the configured repositories failed (Docker Repository),
…

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How Do You Install Kubernetes on an AWS Instance of RedHat Linux?

03/13/201709/03/2019 0 Comments

Problem scenario: You are using RHEL 7.x via AWS. You want to install Kubernetes. What do you do?

Solution
1. Log into the Linux server as ec2-user. Then run this command:
sudo yum-config-manager –enable rhui-REGION-rhel-server-extras rhui-REGION-rhel-server-optional

2. Create this file: /etc/yum.repos.d/kubernetes.repo
3. Have this be the content of the file (with the first line being “[kubernetes]” and the last line ending in “…

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How Do You Deploy a Kubernetes Cluster in AWS Using an Ubuntu Linux Instance?

03/13/201710/13/2020 0 Comments

Updated on 10/13/20.

Problem scenario
You want to deploy a Kubernetes cluster in AWS. You have an Ubuntu server (e.g., with a nano flavor in AWS or a minimally powered Azure instance). It has no software packages installed on it (e.g., it does not have Docker or Kubernetes). How do you deploy Kubernetes in AWS?

Solution
Warning: This will automatically create EC2 servers in you AWS account behind the scenes.

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How Do You Compile a C++ Program When You Get “Gcc: Error Trying to Exec ‘cc1plus’: Execvp: No Such File or Directory”?

03/13/201708/30/2019 0 Comments

Problem scenario: When trying to compile a C++ program (e.g., $ gcc hello.cpp), you receive this error:
“gcc: error trying to exec ‘cc1plus’: execvp: No such file or directory”

What do you do?

Solution
Install gcc-c++. For a RedHat distribution of Linux, use this command:

yum -y install gcc-c++

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How Do You Enable Virtualization Technology (VTx) with an HP Probook?

03/12/201701/20/2021 0 Comments

Problem scenario: You want to use Oracle VirtualBox or some other hosted hypervisor with your HP Probook laptop. You need “Virtualization Technology (VTx)” enabled. How do you do this?

Solution

1. Boot up. When you see the “HP” splash screen (a blue image with a black background), press F10.

2. At the prompt, “Log in as a Guest User” choose “Yes.” (This step may be crucial to your success.)

…

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How Do You Write a C Program to Writes Hexadecimal Numbers 1 Through F Each on New Lines of a New File?

03/11/201708/30/2019 0 Comments

Problem scenario: Using the C programming language, you want to write a program that produces a file (we’ll call it contint.txt) that has the following content:

1
2
3
4
5
6
7
8
9
a
b
c
d
e
f

Solution
Overview of the approach: Hexadecimal numbers use base 16.

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How Do You Comment out a Line in PHP?

03/10/201706/04/2019 0 Comments

Problem scenario
You want to try some .php scripts or web pages without certain lines of code. How do you comment out an individual line?

Solution
Use this at the beginning of a line of code: //

Example: //this text will do nothing in the .php script

To comment out multiple lines, use this at the beginning of the first line: /*
Then conclude the multi-line comment with this:

…

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How Do You Troubleshoot Connecting to a Postgres Database When You Get the Error “FATAL: Ident Authentication Failed”?

03/09/201706/05/2019 0 Comments

Problem scenario
You are trying to establish a connection with a username and password to a Postgres database using PHP. You have a PHP file like this:

<?php
   $host        = “host=127.0.0.1”;
   $port        = “port=5432”;
   $dbname      = “dbname=contint”;
   $credentials = “user=contint password=excellent”;

   $db = pg_connect( “$host $port $dbname $credentials” );
   if(!$db){
      echo “Error : Unable to open database\n”;

…

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The Latest News on The Law and Technology

03/09/201708/23/2019 0 Comments

The news below is focused on the legal issues of computing, intellectual property (copyrights, patents and trademarks), science and technology. The external links are to reputable websites.

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