How to install Virtual box Guest additions on CentOs 8, ake CentOS 8 full screen in Virtual box

This virtualbox tutorial will show you how to install Virtual box Guest additions on CentOs 8.

When this process is done you will be able to make CentOS 8 full screen in Virtual box, so in affect the video shows how to make Centos 8 full screen in Virtual box.

The command that i run to download the relevant packages are:

sudo yum install tar bzip2 kernel-headers perl gcc make elfutils-libelf-devel

How to use snapshots on Virtualbox

This Virtualbox tutorial will show you how to take a snapshot on Virtualbox. First you will see how to take a snapshot of a running virtual machine. You will then see how to restore the snapshot. Snapshots allow you to save the state of a virtual machine; this can be useful when you want to test something, or you’re about to make a change to that virtual machine, and you need to be able to roll back to a working instance. Snapshots have saved me on numerous occasions and are an excellent feature!

How to Generate a CSR on CentOS 8

This video will show you how to generate a Certificate Signing Request CSR on CentOS 8.

A CSR is normally sent to a certificate provider who will supply you with a certificate based from the CSR.

This video uses CentOS 8 Linux however the process should be much the same on all Linux operating systems.

The commands in this video are:

  • sudo yum install openssl
  • openssl req -new -newkey rsa:2048 -nodes -keyout yourkeyname.key yourdomainname.csr

Unable to open primary script

This Video will show you how to solve the error: unable to open primary script permission denied on Centos 8.

In this video i was trying to install moodle and when i went to access the site, I kept getting an error. In the Apache logs i could see the error: unable to open primary script: ‘Unable to open primary script varwwwhtmlmoodleindex.php (Permission denied)

When i delved into the error i could see that it was selinux was causing the issue.

You can disable selinux on the fly by entering: sudo setenforce 0

but to permanently disable you should edit the/etc/selinux/config file and

set selinux to disabled SELINUX=disabled

 

How to ensure a service or program starts on boot on Centos Linux

This Video will show you how to ensure that a service or program starts on boot on Linux. This video was recorded on CentOS 8 but the method shoudl work on most Linux Distros including Ubuntu.

The command that you need to run is:

sudo chkconfig servicename on

This command will ensure that the service starts on boot on Linux

Java keystore tutorial: How to export a Certificate from a Java Keystore

This Java Keytool Tutorial will show you how to export a Certificate from a Java Keystore.

To begin you will first run (Note ensure that you update the relvnet commands to reflect your Keystore, alias and certificate names) :

keytool -list -keystore keystore.jks

to see what certificates reside in the java keystore.

Next you will run:

keytool -exportcert -alias domain -file domain.der -keystore keystore.jks

to export the Certificate.

Can’t SSH into VirtualBox Machine

This video will show you how to SSH into a VirtualBox Machine. This video is using CentOS although the concepts should be much the same for other Linux Distros. This Linux Tutorial shows you what do to when you can’t SSH into VirtualBox Machine. First you will need to power off your VM. Next you will need to right click, settings, click network, select adopter 2 and enable VirtualBox host only adapter. Once done you will need to power on the machine. Next you will need to make sure that this new connection has an IP address. In CentOS this is done by creating a new network connection in the /etc/sysconfig/network-scripts folder. We then configure this network have a DHCP IP address and restart the network connection. Once done we restart the network, and SSH in to our machine.

 

Sound not working on Mac

This Mac tutorial will show you how to correct sound not working on Mac. It will show you what to check when you have no sound on Mac.

It will show you where to access the Mac Audio settings and the changes need to select your audio outputs.

As part of sound troubleshooting we will access systems preferences the audio and then change our audio output to internal.