Virtualization and Cloud Computing

What is virtualization?

In a nutshell, virtualization is software that separates physical infrastructures to create various dedicated resources. It is the fundamental technology that powers cloud computing.

"Virtualization software makes it possible to run multiple operating systems and multiple applications on the same server at the same time," said Mike Adams, director of product marketing at VMware, a pioneer in virtualization and cloud software and services. "It enables businesses to reduce IT costs while increasing the efficiency, utilization and flexibility of their existing computer hardware."

The technology behind virtualization is known as a virtual machine monitor (VMM) or virtual manager, which separates compute environments from the actual physical infrastructure.

Virtualization makes servers, workstations, storage and other systems independent of the physical hardware layer, said John Livesay, vice president of InfraNet, a network infrastructure services provider. "This is done by installing a Hypervisor on top of the hardware layer, where the systems are then installed."

Definition

•       Virtualization is the ability to run multiple operating systems on a single physical system and share the underlying hardware resources.

•       It is the process by which one computer hosts the appearance of many computers.

•       Virtualization is used to improve IT throughput and costs by using physical resources as a pool from which virtual resources can be allocated.

The Pros of Virtual Machines

1.       Less physical hardware.

2.    Central location to manage all assets. All of your virtual machines can be managed from one  location.

3.    More eco-friendly. If you look at your current configuration, most of your machines are idling along. But, with them virtualized and running on a cluster, you maximize your machines’ potential while saving money on energy costs.

4.    Disaster recovery is quick. Re-deploy virtual machines on your system (once you get the host machine back online) and you can have your system back up and running in no time.

5.    Expansion potentials. With the infrastructure in place, it’s simply a matter of deploying a new machine and configuring. No need to go buy new servers (assuming you didn’t cheap out and buy bottom of the line servers).

6.    System upgrades. The time and heartache of making system images before applying a patch and having a system restore fail are all realities. With the virtual environment, if something goes wrong while applying a patch or update, you can simply roll the virtual machine back to where it was before you applied the patch using a snapshot.

7.    Software licensing. Many software packages (such as Rockwell products) tie a license key to a hard drive ID. In a virtual environment, the hard drive ID stays the same no matter which piece of hardware it is running on.

8.    Supports legacy operating systems. As hardware evolves and operating systems become obsolete, it’s harder to find hardware and software that are compatible. Virtualizing these machines eliminates the operating system compatibility problems. This doesn’t fix the problem of obsolete operating systems that are no longer supported – which is a security risk.

9.    Forward compatibility. As new hardware becomes available, your virtual machines can still run on this new hardware (as long as it is supported by the virtual host software).

10. Use of thin clients. Using a thin client manager, replacement of a bad terminal is as easy as a few clicks and powering on the new unit. Conversely, with a physical machine you’re stuck with re-imaging or building a replacement from scratch.

11. Many of the pros are related to the VMware ESXi/Sphere platform. They’ve done a great job of packing high availability features into their product:

12. Monitor if a virtual machine has stopped running and restart automatically (App High Availability).

13. The ability to move a virtual machine running on one server to another without shutting down the guest virtual machine (VMotion).

14. The ability to move a virtual machine running on one SAN to another without shutting down the guest machine (Storage VMotion).

15. Automatically power on a guest machine on boot of the server.

16. For a more extensive list of features check out the VMWare website.

The Cons of Virtual Machines

1.    Cost. The upfront cost can be much higher and, depending on how high of an availability you want, you’ll need to be willing to design the system for your needs now and in the future.

2.    Complexity. If you’re not familiar with the hardware and network aspects of the whole setup, it can be a daunting task to figure out. Routing rules and VLAN’s continue to add complexity, especially if security is a concern.

3.    Often the hardware is bundled together in one location making a single disaster more likely to cause significant down time. However, there are ways around this.

4.    Hardware keys. Yes, you can use hardware keys. You can bind a USB port to a specific virtual machine. However, you are not able to move the virtual machine without physically moving the key as well.

5.    Add-on hardware. In the past, you weren’t able to add on older PCI hardware and share it with the virtual machine. This has changed, but it doesn’t work 100% of the time. I’d recommend testing it thoroughly before deploying. Of course, this also limits which machine a virtual machine can run on because it will need to be bound to that piece of hardware.

The Traditional Server Concept

l  System Administrators often talk about servers as a whole unit that includes the hardware, the OS, the storage, and the applications.

l  Servers are often referred to by their function i.e. the Exchange server, the SQL server, the File server, etc.

l  If the File server fills up, or the Exchange server becomes overtaxed, then the System Administrators must add in a new server.

l  Unless there are multiple servers, if a service experiences a hardware failure, then the service is down.

l  System Admins can implement clusters of servers to make them more fault tolerant.  However, even clusters have limits on their scalability, and not all applications work in a clustered environment.

Pros

l  Easy to conceptualize

l  Fairly easy to deploy

l  Easy to backup

l  Virtually any application/service can be run from this type of setup

Cons

l  Expensive to acquire and maintain hardware

l  Not very scalable

l  Difficult to replicate

l  Redundancy is difficult to implement

l  Vulnerable to hardware outages

l  In many cases, processor is under-utilized

The Virtual Server Concept

l  Virtual servers seek to encapsulate the server software away from the hardware

l  This includes the OS, the applications, and the storage for that server.

l  Servers end up as mere files stored on a physical box, or in enterprise storage.

l  A virtual server can be serviced by one or more hosts, and one host may house more than one virtual server.

l  Virtual servers can still be referred to by their function i.e. email server, database server, etc.

l  If the environment is built correctly, virtual servers will not be affected by the loss of a host.

l  Hosts may be removed and introduced almost at will to accommodate maintenance.

l  Virtual servers can be scaled out easily.

l  If the administrators find that the resources supporting a virtual server are being taxed too much, they can adjust the amount of resources allocated to that virtual server

l  Server templates can be created in a virtual environment to be used to create multiple, identical virtual servers

l  Virtual servers themselves can be migrated from host to host almost at will.

Pros

l  Resource pooling

l  Highly redundant

l  Highly available

l  Rapidly deploy new servers

l  Easy to deploy

l  Reconfigurable while services are running

l  Optimizes physical resources by doing more with less

Cons

l  Slightly harder to conceptualize

l  Slightly more costly (must buy hardware, OS, Apps, and now the abstraction layer)

Virtualization Status

l  Offerings from many companies

l  e.g. VMware, Microsoft, Sun, ...

l  Hardware support

l  Fits well with the move to 64 bit (very large memories) multi-core (concurrency) processors.

l  Intel VT (Virtualization Technology) provides hardware to support the Virtual Machine Monitor layer

l  Virtualization is now a well-established technology

Hypervisor

•       A hypervisor or virtual machine manager/monitor (VMM), or virtualization manager, is a program that allows multiple operating systems to share a single hardware host. 

•       Each guest operating system appears to have the host's processor, memory, and other resources all to itself. However, the hypervisor is actually controlling the host processor and resources, allocating what is needed to each operating system in turn and making sure that the guest operating systems (called virtual machines) cannot disrupt each other.

Hypervisor: A high-level explanation

The evolution of virtualization greatly revolves around one piece of very important software. This is the hypervisor. As an integral component, this software piece allows for physical devices to share their resources amongst virtual machines running as guests on to top of that physical hardware. To further clarify the technology, it’s important to analyze a few key definitions:

§  Type I Hypervisor: This type of hypervisor is deployed as a bare-metal installation. This means that the first thing to be installed on a server as the operating system will be the hypervisor. The benefit of this software is that the hypervisor will communicate directly with the underlying physical server hardware. Those resources are then paravirtualized and delivered to the running VMs. This is the preferred method for many production systems.

§  Type II Hypervisor: This model is also known as a hosted hypervisor. The software is not installed onto the bare-metal, but instead is loaded on top of an already live operating system. For example, a server running Windows Server 2008R2 can have VMware Workstation 8 installed on top of that OS. Although there is an extra hop for the resources to take when they pass through to the VM – the latency is minimal and with today’s modern software enhancements, the hypervisor can still perform optimally.

§  Guest Machine: A guest machine, also known as a virtual machine (VM) is the workload installed on top of the hypervisor. This can be a virtual appliance, operating system or other type of virtualization-ready workload. This guest machine will, for all intents and purposes, believe that it is its own unit with its own dedicated resources. So, instead of using a physical server for just one purpose, virtualization allows for multiple VMs to run on top of that physical host. All of this happens while resources are intelligently shared between other VMs.

§  Host Machine:  This is known as the physical host. Within virtualization, there may be several components – SAN, LAN, wiring, and so on. In this case, we are focusing on the resources located on the physical server. The resource can include RAM and CPU. These are then divided between VMs and distributed as the administrator sees fit. So, a machine needing more RAM (a domain controller) would receive that allocation, while a less important VM (a licensing server for example) would have fewer resources. With today’s hypervisor technologies, many of these resources can be dynamically allocated.

§  Paravirtualization Tools: After the guest VM is installed on top of the hypervisor, there usually is a set of tools which are installed into the guest VM. These tools provide a set of operations and drivers for the guest VM to run more optimally. For example, although natively installed drivers for a NIC will work, paravirtualized NIC drivers will communicate with the underlying physical layer much more efficiently. Furthermore, advanced networking configurations become a reality when paravirtualized NIC drivers are deployed.

Virtualization in Cloud Computing

Cloud computing takes virtualization one step further:

•       You don’t need to own the hardware

•       Resources are rented as needed from a cloud

•       Various providers allow creating virtual servers:

–      Choose the OS and software each instance will have

–      The chosen OS will run on a large server farm

–      Can instantiate more virtual servers or shut down existing ones within minutes

•       You get billed only for what you used

Suppose you are XYZ.com

XYZ's Solution

l  Host the web site in Amazon's EC2 Elastic Compute Cloud

l  Provision new servers every day, and deprovision them every night

l  Pay just $0.10* per server per hour

l  * more for higher capacity servers

Let Amazon worry about the hardware!

Cloud computing

Cloud computing, also known as on-demand computing, is a kind of Internet-based computing, where shared resources, data and information are provided to computers and other devices on-demand. It is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications and services) that can be rapidly provisioned and released with minimal management effort. Cloud computing and storage solutions provide users and enterprises with various capabilities to store and process their data in third-party data centers. It relies on sharing of resources to achieve coherence and economies of scale, similar to a utility (like the electricity grid) over a network. At the foundation of cloud computing is the broader concept of converged infrastructure and shared services.

Cloud computing takes virtualization to the next step

l  You don’t have to own the hardware

l  You “rent” it as needed from a cloud

l  There are public clouds

l  e.g. Amazon EC2, and now many others (Microsoft, IBM, Sun, and others ...)

l  A company can create a private one

l  With more control over security, etc.

Goal 1 – Cost Control

l  Cost

l  Many systems have variable demands

l  Batch processing (e.g. New York Times)

l  Web sites with peaks (e.g. Forbes)

l  Startups with unknown demand (e.g. the Cash for Clunkers program)

l  Reduce risk

l  Don't need to buy hardware until you need it

Goal 2 - Business Agility

l  More than scalability - elasticity!

l  Ely Lilly in rapidly changing health care business

l  Used to take 3 - 4 months to give a department a server cluster, then they would hoard it!

l  Using EC2, about 5 minutes!

l  And they give it back when they are done!

l  Scaling back is as important as scaling up

Goal 3 - Stick to Our Business

l  Most companies don't WANT to do system administration

l  Forbes says:

l  We are is a publishing company, not a software company

l  But beware:

l  Do you really save much on sys admin?

l  You don't have the hardware, but you still need to manage the OS!

How Cloud Computing Works

l  Various providers let you create virtual servers

l  Set up an account, perhaps just with a credit card

l  You create virtual servers ("virtualization")

l  Choose the OS and software each "instance" will have

l  It will run on a large server farm located somewhere

l  You can instantiate more on a few minutes' notice

l  You can shut down instances in a minute or so

l  They send you a bill for what you use

Cloud Providers

A cloud provider is a company that offers some component of cloud computing – typically Infrastructure as a Service (IaaS), Software as a Service (SaaS) or Platform as a Service (PaaS) – to other businesses or individuals. Cloud providers are sometimes referred to as cloud service providers or CSPs.

The Best Cloud Computing Companies

Types of cloud computing

Cloud computing is typically classified in two ways:

•       Location of the cloud computing

•       Type of services offered

Location of the cloud

Cloud computing is typically classified in the following three ways:

•       Public cloud: In Public cloud the computing infrastructure is hosted by the cloud vendor at the vendor’s premises. The customer has no visibility and control over where the computing infrastructure is hosted. The computing infrastructure is shared between any organizations.

•       Private cloud: The computing infrastructure is dedicated to a particular organization and not shared with other organizations. Some experts consider that private clouds are not real examples of cloud computing. Private clouds are more expensive and more secure when compared to public clouds. Private clouds are of two types: On-premise private clouds and externally hosted private clouds. Externally hosted private clouds are also exclusively used by one organization, but are hosted by a third party specializing in cloud infrastructure. Externally hosted private clouds are cheaper than On-premise private clouds.

•   Hybrid cloud: Organizations may host critical applications on private clouds and applications with relatively less security concerns on the public cloud. The usage of both private and public clouds together is called hybrid cloud. A related term is Cloud Bursting. In Cloud bursting organization use their own computing infrastructure for normal usage, but access the cloud using services like Salesforce cloud computing for high/peak load requirements. This ensures that a sudden increase in computing requirement is handled gracefully.

•       Community cloud: involves sharing of computing infrastructure in between organizations of the same community. For example all Government organizations within the state of California may share computing infrastructure on the cloud to manage data related to citizens residing in California.

Type of services offered

Classification based upon service provided.Based upon the services offered, clouds are classified in the following ways:

Infrastructure as a service (IaaS) involves offering hardware related services using the principles of cloud computing. These could include some kind of storage services (database or disk storage) or virtual servers. Leading vendors that provide Infrastructure as a service are Amazon EC2, Amazon S3, Rackspace Cloud Servers and Flexiscale.

Platform as a Service (PaaS) involves offering a development platform on the cloud. Platforms provided by different vendors are typically not compatible. Typical players in PaaS are Google’s Application Engine, Microsofts Azure, Salesforce.com’s force.com .

Software as a service (SaaS) includes a complete software offering on the cloud. Users can access a software application hosted by the cloud vendor on pay-per-use basis. This is a well-established sector. The pioneer in this field has been Salesforce.coms offering in the online Customer Relationship Management (CRM) space. Other examples are online email providers like Googles gmail and Microsofts hotmail, Google docs and Microsofts online version of office called BPOS (Business Productivity Online Standard Suite).

David Linthicum classification:

The above classification is well accepted in the industry. David Linthicum describes a more granular classification on the basis of service provided.

•       These are listed below:

•       Storage-as-a-service

•       Database-as-a-service

•       Information-as-a-service

•       Process-as-a-service

•       Application-as-a-service

•       Platform-as-a-service

•       Integration-as-a-service

•       Security-as-a-service

•       Management/Governance-as-a-service

•       Testing-as-a-service

•       Infrastructure-as-a-service

OpenStack

OpenStack is a usual term while considering Cloud computing and its technologies. Most people Google to know what OpenStack is. Let us understand the basics of OpenStack.

What is OpenStack?

          OpenStack is a free and open-source software platform for cloud-computing, mostly deployed as an infrastructure-as-a-service (IaaS). The software platform consists of interrelated components that control hardware pools of processing, storage, and networking resources throughout a data center. Users either manage it through a web-based dashboard, through command-line tools, or through a RESTful API. www.openstack.org released it under the terms of the Apache License.

         

Some refer OpenStack as the Operating System for Cloud while some others say it as the software that helps to build Cloud environment. And while considering the installation of OpenStack, we tend to call it as a software or platform that helps to build a cloud environment.

Why OpenStack?

OpenStack is an open source, Infrastructure as a Service (Iaas) platform that helps to create and manage scalable, elastic cloud computing for both public and private cloud. This is aimed to support interoperability between cloud services and to build a highly scalable and productive cloud environment. OpenStack is freely available under the license of Apache 2.0.

OpenStack History:

Rackspace hosting and NASA on July 2010, jointly launched OpenStack as an open-source cloud software initiative. The project aimed at helping organizations to run cloud computing services on a standard hardware. OpenStack is enriched with the offerings of both the organizations; Rackspace provided the code for a powerful storage, content delivery services and the production servers whereas the powerful technology of Nebula (open source cloud computing program that provides on-demand computing power for NASA researchers and scientists), Networking and data storage cloud service was the offerings from NASA’s end. Since September 2012, OpenStack officially became an independent non-profit organization.

OpenStack Functionality

•       Amazon AWS Interface Compatibility

•       Flexible Clustering and Availability Zones

•       Access Control List (ACL) with policies management

•       Network Management, Security Groups, Traffic Isolation

•       Cloud Semantics and Self-Service Capability

•       Image registration and image attribute manipulation

•       Bucket-Based Storage Abstraction (S3-Compatible)

•       Block-Based Storage Abstraction (EBS-Compatible)

•       Hypervisor support: Xen, KVM, VMware Vsphere, LXC, UML and MS HyperV

How is OpenStack used in a cloud environment?

•       The cloud is all about providing computing for end users in a remote environment, where the actual software runs as a service on reliable and scalable servers rather than on each end users computer. Cloud computing can refer to a lot of different things, but typically the industry talks about running different items "as a service"—software, platforms, and infrastructure. OpenStack falls into the latter category and is considered Infrastructure as a Service (IaaS). Providing infrastructure means that OpenStack makes it easy for users to quickly add new instance, upon which other cloud components can run. Typically, the infrastructure then runs a "platform" upon which a developer can create software applications which are delivered to the end users.

OpenStack Architecture

Architecture of OpenStack includes below components

OpenStack components

 OpenStack in Different Cloud Service Provider

OpenStack components Details

KeyStone (Identity Service)

•       The identity service performs the following functions: Tracking users and their permissions and Providing a catalog of available services with their API endpoints.

•       Keystone involves the following things: User, Credentials, Tenant, Service, Role, Service and Endpoint.

Glance

•       The OpenStack Image Service (glance) enables users to discover, register, and retrieve virtual machine images. It offers a REST API that enables you to query virtual machine image metadata and retrieve an actual image.

•       You can store virtual machine images made available through the Image Service in a variety of locations, from simple file systems to object-storage systems like OpenStack Object Storage.

Compute

•       Use OpenStack Compute to host and manage cloud computing systems. OpenStack Compute is a major part of an Infrastructure-as-a-Service (IaaS) system.

•       OpenStack Compute interacts with OpenStack Identity for authentication, OpenStack Image Service for disk and server images, and OpenStack dashboard for the user and administrative interface. Image access is limited by projects, and by users; quotas are limited per project (the number of instances, for example). OpenStack Compute can scale horizontally on standard hardware, and download images to launch instances.

Neutron

•       OpenStack Networking mainly interacts with OpenStack Compute to provide networks and connectivity for its instances.

•       Networking provides the networks, subnets, and routers object abstractions. Each abstraction has functionality that mimics its physical counterpart: networks contain subnets, and routers route traffic between different subnet and networks.

Horizon

•       The OpenStack dashboard, also known as Horizon, is a Web interface that enables cloud administrators and users to manage various OpenStack resources and services.

•       The dashboard enables web-based interactions with the OpenStack Compute cloud controller through the OpenStack APIs.

Heat (Orchestration)

•       The Orchestration module provides a template-based orchestration for describing a cloud application, by running OpenStack API calls to generate running cloud applications. The software integrates other core components of OpenStack into a one-file template system. The templates allow you to create most OpenStack resource types, such as instances, floating IPs, volumes, security groups and users. It also provides advanced functionality, such as instance high availability, instance auto-scaling, and nested stacks. This enables OpenStack core projects to receive a larger user base.

Ceilometer

•       The Telemetry module performs the following functions:

•       Efficiently polls metering data related to OpenStack services.

•       Collects event and metering data by monitoring notifications sent from services.

•       Publishes collected data to various targets including data stores and message queues.

Creates alarms when collected data breaks defined rules.

Example