The "long" story of virtualization ...
What and why
Main reasons to adopt virtualization fot IT administrators & Management
- Average 5-10 % of real resources used on traditional HW
- Hardware failure
- Single OS on top of Hardware
IT managers duties:
- Security
- Hw & Sw maintenance
- Hw Cooling and power management
Where are we ?
In the late 1990s, VMware introduced a technology that enabled most of the code to execute directly on the CPU without the requirement for translation or emulation.
The concept of the “hypervisor” – a platform upon which IT could create and run virtual machines comes from Mainframes
For years, VMware and its patents ruled the realm of virtualization. On the server side, running on bare metal, VMware's ESX became the leading Type 1 (or native) hypervisor. On the client side, running within an existing desktop operating system, VMware Workstation was among the top Type 2 (or hosted) hypervisors.
Over the years, some interesting open-source projects emerged, including Xen and Quick EMUlator (QEMU). Neither was as fast or as flexible as VMware, but they set a foundation that would prove worthy down the road. Around 2005, Advanced Micro Devices (AMD) and Intel created new processor extensions to the x86 architecture. These extensions provided hardware assistance for dealing with privileged instructions.
Called AMD-V and VT-x by AMD and Intel respectively, these extensions changed the landscape, eventually opening server virtualization to new players.
For more details on Xen and KVM: Xen and KVM
Even Microsoft eventually got into the game with the release of Hyper-V in 2008. (Archi similar to Xen)
When virtualization essentially became free, or at least accessible without expensive licensing fees, new use cases came to light. Most notably, Amazon began to use the Xen platform to rent some of its excess computing capacity to thirdparty customers. Through their application programming interfaces (APIs), Amazon kicked off the revolution of elastic cloud computing, where the applications could self-provision resources to fit their workloads.
Progressively, open-source hypervisors have matured and become pervasive in cloud computing. Technology vendors developing solutions for virtual environments are increasingly required to support all major hypervisors (Xen and KVM)
With this hypervisor parity, innovation became focused on the private/public cloud hardware architectures and the software ecosystems that surround them: storage architectures, softwaredefined networking, intelligent and autonomous orchestration, and application APIs. This leads to new actors like Nutanix ant its HCI (Hyper Convergence Infrastructure) to emerge.
Legacy server applications are slowly retiring to give way to elastic, self-defining cloud applications (although they will coexist side by side for some time).
Server and Desktop Virtualization
Desktop Virtualization is a response to increasing numbers of employees working remotely and from multiple devices.
Server virtualization is an answer for companies that need to diversify workloads and maximize server efficiency
Terminology
Hardware Abstraction Layer
Host Operating System
Guest Operating System
Partitioning, isolation, sharing of resources
Images lifecycle
Virtual Network
Hypervisors
A hypervisor provides software to manage virtual machine access to the underlying hardware. The hypervisor creates, manages, and monitors virtual machines. There are 2 types: Type 1 (Bare metal) and Type 2 (Hosted). Hypervisors come with Management Software that:
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Controls the failover
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Authorize dynamic over-allocation of resources (Type 1 only, can specify static too)
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Manages the VMs lifecycle (start/stop)
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Manages the VMs images location (lift and shift)
Note
The term Lift and Shift is used for migration from OnPremise Infrastructure to Cloud Infrastructure Another approach is Transform and Move
Type 1 Hypervisor
Info
Citrix Xen Server (free), VMware vSphere (former VMware ESXi and VMware ESX), Microsoft Hyper-V Server, Parallels Server Bare Metal, Oracle vm server (free).
Type 2 Hypervisor
Info
Microsoft (Microsoft VirtualPC, Microsoft Virtual Server), Parallels (Parallels Desktop, Parallels Server), Oracle VM VirtualBox (free), VMware (VMware Fusion, VMware Player, VMware Server, VMware Workstation), free (QEMU : x86 emulator), KVM (free)
Containers
Info
Linux-VServer (isolating processes into user spaces) ; chroot (isolating the change of root) ; BSD Jail ; LXC : free; Docker.