Information Technology Reference
In-Depth Information
Summary
We started the chapter with some tutorials about basic cloud setup, such as creating and
importing/exporting virtual machine templates and service templates. These are basic
necessities for starting your cloud infrastructure; taking care of them also makes future
deployments and provisioning of instances and resources easier to manage in the future.
Installing guest tools on your VM or guest OS will increase its capabilities, such as being
able to make use of hardware graphical acceleration or be seamlessly integrated into your
desktop environment if you are using Type 2 hypervisors.
Knowing how to create clones and snapshots of virtual machine states will help in the
fast creation and backup of VMs. A snapshot and a clone have similar uses, but they have
fundamental differences. A clone is a full independent copy of a virtual machine from its
settings to the contents of its hard drive, while a snapshot is essentially just a save of a
specific state of a virtual machine and so is coupled to that specific virtual machine. The
snapshot can be used to quickly jump between states of a VM and will be very useful in a
test environment to help determine the difference between the states from before and after
an error. Each snapshot is dependent on the original VM and will work for only that VM.
A clone is an independent VM from its parent and can be used in any way after creation;
it is simply a good way of replicating a VM in its specific state. It is also useful for testing
purposes, especially for testing software installations and deployments so that you can
work on a full environment without compromising the original VM in case something
goes wrong.
You also learned in this chapter the various parts of a virtualized environment. The first
one would be the virtual disk. It is simply a representation of a hard disk that the VM uses
to store its files. On the networking side there is the virtual switch, which is in every way
equivalent in function to the physical switch with the added bonus of having a lot more
ports, which means that an entire virtual network can be supported by a single virtual
switch bound to a physical NIC.
VLAN is not the actual virtual representation of a LAN as in connecting some VMs in
a networking using a vSwitch. Rather, it is a concept of further subdividing a portion of
a larger network so that those specific nodes can act as if they are connected locally even
though they may span different geographical locations and different segments of a larger
network. This means that they are able to communicate easily without the need for further
authentication or encryption because they are treated as local connections and not as outside
connections as they most probably are. A counterpart to the VLAN is the virtual storage
network (VSAN). In the same vein, a VSAN is a way to further subdivide a large SAN into
smaller ones. For example, you can subdivide a SAN with 10 servers into any combination
into 5 VSANs composed of 2 servers each.
Once the infrastructure and environment has been set up, what comes next is data and
process migration. Cloud technology allows easy data and process migration, and all of
this can be done by the provider, allowing the local technical department to deal with other
important issues.
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