Getting Started with Cloud Computing, Part 2: Cloud Computing Service Models
My personal notes from the fundamentals of cloud computing by David Davis offered by PluralSight. These notes will continue to be updated and improved as I continue to review and research this course to “really” understand it. I would try as much as possible to reference every author I find their resources to be useful. Much appreciation to Grow with GoogleAfrica and Andela who gave me this opportunity to learn.
In part 1, we talked about cloud computing then process to the traits of the cloud. Finally, we then highlight the history of cloud computing stating all the major successes that lead to the current cloud computing revolution.
Now we going to look at the different types of service models of cloud solutions usually offered by cloud-computing providers.
The cloud-computing providers offer their “services” according to different models, of which the three standard models per NIST are: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). These models offer increasing abstraction; they are thus often portrayed as layers in a stack: infrastructure-, platform- and software-as-a-service(see figure below). We would begin out the discussion with Infrastructure as a service (IaaS).
Infrastructure as a service (IaaS)
“Infrastructure as a service” (IaaS) is the most basic service, and provides a server, or servers, in the cloud, along with storage. IaaS deals with raw computing capacity, without the responsibilities of installation or maintenance. IaaS refers to online services that provide high-level APIs used to dereference various low-level details of underlying network infrastructure like physical computing resources, location, data partitioning, scaling, security, backup etc.
What is Virtualization
Virtualization is a logical division of physical computing resources. It started in the 1960s as a way to split up mainframe resources. There are many resources that can be virtualized -server (compute), storage and network.
It became popular with VMWARE ESX Server launch in 2001. With VM ESX Enterprise were able to virtualize their physical host and significantly reduce the number of physical servers in the data center and from their VMware popularity skyrocketed and today it is used in the majority of all the data centers around the world. So the cloud service provider use a virtualization hypervisor, a software that makes virtualization possible. They use a hypervisor in their datacenters across their hundreds of thousands of physical servers to run many virtual machines for many different customers.
What is a Virtual Machine
Running on a hypervisor, a virtual machine is a software-base instance of a physical server where a guest operating system has access to emulated virtual hardware. The operating systems and applications loaded on the guest virtual machines don’t know the difference. They don’t know that they are running on virtual hardware and that there are other virtual machines. They think they have full access to the physical hardware, to the physical server. So they are provided virtual resources from the hypervisor.
Virtualization is not cloud computing unless you are running the virtual machines over the internet.
What is a Container
A container is operating-system level virtualization where the OS kernel provides isolated user spaces to run specific applications. Containers have been around for a long time, In fact containers have been in use just about ever since Unix or Linux have been in use. And with containers, the operating system is sliced up into isolated secure areas to run specific applications. So with containers, there is still just one operating system. There is not multiple operating-system like with virtualization. Containers can actually be run inside a virtual machine on a virtualization hypervisor. Containers have much less overhead (due to lack of a hypervisor) and faster startup times than virtual machines. Also, container capacity auto-scales dynamically with the computing load, which eliminates the problem of over-provisioning and enables usage-based billing.
So the cloud uses both virtualization and containerization. Now let's learn about the different types of IaaS cloud offering.
Private, Hybrid and Public Clouds
Private cloud refers to a model of cloud computing where IT services are provisioned over private IT infrastructure for the dedicated use of a single organization. Private clouds are run on-premises, meaning they are run in your building, at your own data center. Those types of clouds are for your company to leverage. They’re run on your own infrastructure and are usually managed via internal resource.
When we talk about Iaas, we are typically referring to the public cloud. That is kind of the natural assumption. Services like Amazon Web Services EC2 and Azure Virtual Machines. A public cloud is one based on the standard cloud computing model, in which a service provider makes resources, such as virtual machines (VMs), applications or storage, available to the general public over the internet. Public cloud services may be free or offered on a pay-per-usage model.
Unfortunately, there is no real hybrid cloud. It's not a real place that you can run your applications. What the hybrid cloud means is that you have connected your private cloud to your public cloud to create this hybrid. So the definition of Hybrid cloud is that these two clouds are working together by allowing data and applications to be shared between them
Virtualization vs Private Cloud
Iaas Pricing Models
Service Level Agreement
Migrating to the Cloud
What is public cloud? - Definition from WhatIs.com
A public cloud is one based on the standard cloud computing model, in which a service provider makes resources, such as…