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LUX 263 - Linux System Administration III
Lesson 4: Chapter 17, Virtual Machines
Objectives:
This lesson discusses scheduled events in Linux. Objectives important
to this lesson:
- Virtual machines
- gnome-boxes
- QEMU/KVM
- VMware Player
- Cloud computing
- AWS
Concepts:
Chapter 17
The chapter opens with a list of benefits of using virtual machines instead
of dedicating individual boxes for each server you may need in your organization.
As you are aware, some of the virtues can also be drawbacks, depending
on your setup or the nature of the problem you might have.
- Isolation - Each virtual machine on a specific box (and there can
be several on each box) is independent of the others, as far as software.
A software failure would bring down only the one VM. However, each VM
is dependent on the same processors, hard drives, motherboard, etc.
as the others on the same box, which means a hardware failure would
take down all the VMs running on that box.
- Quick recovery - A VM that goes down due to a non-hardware problem
can be brought back up in minutes from a saved image (snapshot).
The text lists eight virtual box products on page 662 that can be parts
of your Virtual Machine solution. It follows the list with discussions
on several of them.
- gnome-boxes
- This is essentially a gnome interface that can serve as a front end
for a VM, or for a remote system. It features the ability to log in
to a virtual machine on your own computer or on another computer across
a network connection. At Baker, we have typically run Linux VMs on computers
running Windows, but this approach allows you to set up a Windows or
Linux VM on a computer running Linux.
- QEMU/KVM -
This is a more capable utility, in that it acts as a hypervisor, a VM
manager, that can emulate hardware that is different from the actual
hardware on the host machine.
- virt-manager - This
is not a full solution, but a front end to manage the VMs set up under
another system, typically under QEMU/KVM.
- VMware
Player - This is one of two classic VM solutions used in classrooms,
the other being Virtualbox.
Both have been used at Baker at different times. Note that, like other
products discussed in this chapter, there are downloadable versions
for computers running Linux and for computers running Windows.
The chapter ends with a discussion about cloud computing which
means, in this case, running your virtual machines on computers that are
somewhere "in the cloud". This phrase can mean a lot of different
things. The focus of this discussion is a purchased service from a dependable
vendor who will provide a reliable experience to your organization regardless
of their location. Four solutions are briefly discussed, but the most
space is devoted to Amazon's AWS solution.
AWS stands for Amazon Web Services. You can sign up for a 12-month
free account with Amazon, who is a major vendor in the cloud services
and cloud computing field. 
If you click the image on the right, you will be taken to Amazon's
AWS Educate page which presents Amazon's interest in educational use
of their services. To activate educational status for your account, first
you have to register for an account with AWS. Once you do that, you can
get the account number assigned to you, and use that in your application
for AWS Educate.
As you explore Amazon's website, be careful to click the icons for the
free services, since we don't want to have anyone signing up for professional
level charges in the classroom or at home.
Once you have finished the registration steps, you can sign in to your
account and run any of the tutorials that apply to you. In the case of
our class,you need to run and follow the instructions in the tutorial
on launching
a Linux virtual machine. Once again, pay attention to the prompts
and be sure to make choices that are free. (Free as in "Amazon isn't
going to charge for them.") This applies to machines, space, processor
allocation, etc.
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