How Do You Install VirtualBox when you Encounter an Error Message “Unable to install VirtualBox as download failed … not (yet) available (404 Not Found)”?

Problem scenario
You try to install VirtualBox on a Linux server via the “Software” section of your GUI. It fails with an error message like this: “Unable to install VirtualBox as download failed … not (yet) available (404 Not Found)”

Run a command like one of the following depending on the type of Linux you have.

If you have a Debian distribution of Linux (such as Ubuntu or Mint): sudo apt -y update

If you have a Red Hat distribution of Linux (such as CentOS,

How Do You Troubleshoot a VirtualBox VM saying “failed unmounting /cdrom”?

Problem scenario
In VirtualBox you are trying to boot a VM, but you get “failed unmounting /cdrom”. You see no option to unmount or remove the CD ROM. What should you do?

Possible Solution #1
Restart VirtualBox. Close it. Reopen it.

Possible Solution #2
Reboot the computer hosting/running VirtualBox.

What is the Difference between vRealize Automation and vRealize Orchestrator?

VMware makes vRealize Orchestrator and vRealization Automation. How are these products different?

vRealize Orchestrator does automation (with JavaScript, third party plugins etc.) and vRealize Automation provides a service catalog, governance policies, utilization tracking, networking, security and application services. It almost would have made more sense if they swapped names.

To learn more, see this: …

What Does MoRef Mean or Refer to?

What does MoRef mean?

It is a portmanteau of “Managed Object Reference.” It is a data type that comes up in the context of alerts/alarms in vSphere.

(The answer was adapted from page 152 of PowerCLI Cookbook by Sellers.)

“MoRefs are unique identifiers assigned to objects at the time of their creation.” (Taken from page 202 of PowerCLI Cookbook by Sellers.)

How Do You Solve the Login Prompt Message “Cloud-init…modules:final…Datasource”?

Problem scenario #1
You just installed Linux on a new VM. You boot up your Debian distribution of Linux (e.g., running via Oracle VirtualBox). You see at the login prompt, “cloud-init…running modules:config…DataSourceNone…[WARNING]: Used fallback datasource”. What should you do?

Problem scenario #2
You recently created a new server. When you boot your Debian/Ubuntu/Mint server, it seems to hang with an error message about “cloud-init cc_final_message_py [warning]: used fallback datasource.” What should you do?

What is the Difference between a Data Structure Container and a Virtual Environment Container?

You have heard about different types of containers and seek a disambiguation. Can containers be disambiguated?

One type of container is a virtual environment like Docker. Another type of container is a data structure of a programming language such as an array, set, list, tuple, or dictionary. These different types of collections of data are called containers.

What is Software-Defined Infrastructure?

What is software-defined infrastructure?

There is no universally accepted definition of software-defined infrastructure (according to Techopedia).

We define it as infrastructure that is provisioned and controlled by software. (There is physical infrastructure that powers or underlies SDI.) The provisioning and configuring of virtual machines is one example of SDI. OpenStack and Ericsson’s SDI Manager are other examples of SDI.