Cloud and Virtualization Summary (19.3)
The following is a summary of each topic in the chapter and some questions for your reflection.
What Did I Learn in this Module? (19.3.1)
• Cloud and Cloud Services—In general, when talking about the cloud, we are talking about data centers, cloud computing, and virtualization. Data centers are usually large facilities which provide massive amounts of power, cooling, and bandwidth. Only very large companies can afford their own data centers. Most smaller organizations lease the services from a cloud provider.
Cloud services include the following:
• SaaS – Software as a service
• PaaS – Platform as a service
• IaaS – Infrastructure as a service
There are four primary cloud models:
• Public clouds – Cloud-based applications and services offered in a public cloud are made available to the general population.
• Private clouds – Cloud-based applications and services offered in a private cloud are intended for a specific organization or entity, such as the government.
• Hybrid clouds – A hybrid cloud is made up of two or more clouds, where each part remains a separate object, but both are connected using a single architecture.
• Community clouds – A community cloud is created for exclusive use by a specific community. The differences between public clouds and community clouds are the functional needs that have been customized for the community.
Virtualization is the foundation of cloud computing. Without it, cloud computing, as it is most-widely implemented, would not be possible. Virtualization means creating a virtual rather than physical version of something, such as a computer. An example would be running a “Linux computer” on your Windows PC.
• Virtualization—One major advantage of virtualization is overall reduced cost:
• Less equipment is required – Virtualization enables server consolidation, which requires fewer physical devices and lowers maintenance costs.
• Less energy is consumed – Consolidating servers lowers the monthly power and cooling costs.
• Less space is required – Server consolidation reduces the amount of required floor space.
These are additional benefits of virtualization:
• Easier prototyping – Self-contained labs, operating on isolated networks, can be rapidly created for testing and prototyping network deployments.
• Faster server provisioning – Creating a virtual server is far faster than provisioning a physical server.
• Increased server uptime – Most server virtualization platforms now offer advanced redundant fault tolerance features.
• Improved disaster recovery – Most enterprise server virtualization platforms have software that can help test and automate failover before a disaster happens.
• Legacy support – Virtualization can extend the life of OSs and applications providing more time for organizations to migrate to newer solutions.
The hypervisor is a program, firmware, or hardware that adds an abstraction layer on top of the physical hardware. The abstraction layer is used to create virtual machines which have access to all the hardware of the physical machine such as CPUs, memory, disk controllers, and NICs. Each of these virtual machines runs a complete and separate operating system.
Type 1 hypervisors are also called the “bare metal” approach because the hypervisor is installed directly on the hardware. Type 1 hypervisors are usually used on enterprise servers and data center networking devices.
A Type 2 hypervisor is software that creates and runs VM instances. The computer, on which a hypervisor is supporting one or more VMs, is a host machine. Type 2 hypervisors are also called hosted hypervisors. This is because the hypervisor is installed on top of the existing OS, such as macOS, Windows, or Linux. Then, one or more additional OS instances are installed on top of the hypervisor. A big advantage of Type 2 hypervisors is that management console software is not required.
For now, Bob is suggesting that Marcy and Vincent use the cloud for data storage. They understand that it is a subscription service, but it will allow them to maintain their data more securely and it will be less expensive than buying their own data storage and server. As you now know, there are many other services provided by the cloud. Marcy and Vincent may eventually desire some of these services as well. Have you ever had your hard drive go down and not be able to recover all your files? What if this happened to a computer or even a server at your school or work? Does your school or work network use other cloud services? If so, do you know what they are and why they were selected? If you were in Marcy and Vincent’s situation, what cloud services would you consider using, besides data storage?