- What,Why & How Virtualization?
- Emulation Vs Simulation
- Server virtualization in detail
- Over Commit
- Thick and Thin provisioning
- Network Operations – types
What is virtualization ?
Virtualization is technology that lets you create useful IT services using resources that are traditionally bound to hardware.
Emulation Vs Simulation
In computing, the emulator is a hardware or software that enables one device (named Host) to function like other systems. Simulation is a software which can mimic a certain process or object.
Types of Virtualization ?
● Storage function virtualisation – is the pooling of multiple physical storage arrays from SANs and making them appear as a single virtual storage device.
● Desktop Virtualization – is technology that lets users simulate a workstation load to access a desktop from a connected device remotely or locally
● Network function virtualization – is the decoupling of network functions from proprietary hardware appliances and running them as software in virtual machines (VMs).
● VDI – In VDI, a hypervisor segments servers into virtual machines that in turn host virtual desktops, which users access remotely from their devices
Server virtualization in detail
Full Virtualization(Hardware Assisted/ Binary Translation )
In full virtualization, guest OS is completely isolated by the virtual machine from the virtualization layer and hardware.
Software Assisted – Full Virtualization (BT – Binary Translation )
It completely relies on binary translation to trap and virtualize the execution of sensitive, non-virtualizable instruction sets. It emulates the hardware using the software instruction sets.
list of software which will fall under software assisted (BT).
● VMware workstation (32Bit guests)
● Virtual PC
● VirtualBox (32-bit guests)
● VMware Server
Hardware-Assisted – Full Virtualization (VT)
Hardware-assisted full virtualization eliminates the binary translation and it directly interrupts with hardware using the virtualization technology which has been integrated on X86 processors since 2005 (Intel VT-x and AMD-V).
● VMware ESXi /ESX
The following virtualization type of virtualization falls under hypervisor type 2 (Hosted).
● VMware Workstation (64-bit guests only )
● Virtual Box (64-bit guests only )
● > VMware Server (Retired )
It doesn’t need to simulate the hardware for the virtual machines. The hypervisor is installed on a physical server (host) and a guest OS is installed into the Environment. Virtual guests are aware that it has been virtualized, unlike the full virtualization (where the guest doesn’t know that it has been virtualized) to take advantage of the functions. In this virtualization method, guest source codes will be modified with sensitive information to communicate with the host. Below are the examples of Paravirtualization
● IBM LPAR
● Oracle VM for SPARC (LDOM)
● Oracle VM for X86 (OVM)
Virtualization and cloud
Overcommitting is the process of allocating more virtualized CPUs or memory than there are physical resources on the system. CPU overcommit allows under-utilized virtualized servers or desktops to run on fewer servers which saves power and money
Thick and Thin provisioning
In virtual storage, thick provisioning is a type of storage allocation in which the amount of storage capacity on a disk is pre-allocated on physical storage at the time the disk is created. Thick provisioning contrasts with thin provisioning, which provisions storage on an as-needed basis. Thin provisioning helps to avoid wasted physical capacity and can save businesses on up-front storage costs.
Network Operations – types
Bridged networking connects a virtual machine to a network using the host computer’s Ethernet adapter. Host-only networking creates a network that is completely contained within the host computer. NAT gives a virtual machine access to network resources using the host computer’s IP address.
Memory ballooning is a memory management feature used in most virtualization platforms which allows a host system to artificially enlarge its pool of memory by taking advantage or reclaiming unused memory previously allocated to various virtual machines.
Live migration is a Hyper-V feature in Windows Server. It allows you to transparently move running Virtual Machines from one Hyper-V host to another without perceived downtime. The primary benefit of live migration is flexibility; running Virtual Machines are not tied to a single host machine.
History of cloud
Before emerging the cloud computing, there was Client/Server computing which is basically a centralized storage in which all the software applications, all the data and all the controls are resided on the server side.
If a single user wants to access specific data or run a program, he/she need to connect to the server and then gain appropriate access, and then he/she can do his/her business.
Then after, distributed computing came into picture, where all the computers are networked together and share their resources when needed.
One baremetal system of virtualization,share the baremetal system,high cost for system.the most of isle state of systems made use of cloud.
Challenges in cloud
● Compliance Legal issues
● loss of cloud data.
Types of cloud
Public clouds are cloud environments typically created from IT infrastructure not owned by the end user. Some of the largest public cloud providers include Alibaba Cloud, Amazon Web Services (AWS), Google Cloud, IBM Cloud, and Microsoft Azure.
Private clouds are loosely defined as cloud environments solely dedicated to a single end user or group, where the environment usually runs behind that user or group’s firewall. All clouds become private clouds when the underlying IT infrastructure is dedicated to a single customer with completely isolated access.
A hybrid clouds is a seemingly single IT environment created from multiple environments connected through local area networks (LANs), wide area networks (WANs), virtual private networks (VPNs), and/or APIs.
YAML is a data serialization language that is often used for writing configuration files. Depending on whom you ask, YAML stands for yet another markup language or YAML ain’t markup language (a recursive acronym), which emphasizes that YAML is for data, not documents
A Python script is a reusable set of code that is essentially a Python program — a sequence of Python instructions — contained in a file. You can run the program by specifying the name of the script file to the interpreter. It’s time to create our first script file