Virtualization

[Problem]

As an initial entry and for me to get used to posting content online I figured Id start with a very rudimentary familiarization with a few key terms used frequently with virtualization, in particular, pertaining to the virtualization platform created by VMWare.

[Solution]

To start off you have two key classes in virtualization, type-1 and type-2. Bare-metal means that the virtualization platform runs directly on the host hardware, such as VMWare ESXi. You also have type-2 hypervisors that do not run directly on the hardware but are installed within a traditional operating system, like VMWare workstation, VMWare Fusion, or Parallels.

As noted by VMWare there are several benefits to virtualization:

Cost and Efficiency: When actual resources are calculated within an environment it is noted that memory and CPU utilization is usually barely being used by the operating system, ie you have a domain controller in your office/data center, and the server it resides on has 48GB of memory and dual 8 core CPUs. Over time monitoring shows that the OS has never used more than 15% CPU and 10% memory. With virtualization one would be able to simultaneously run lets say DNS as well as the domain controller instead of “wasting” another server.

Robustness: Using features such as HA, fault tolerance, and vmotion you can easily mitigate the risks of single server failure. High availability or HA, allows for the pooling, so to speak, of vm’s and their underlying hosts into clusters, and should one of the hosts within a cluster have a failure event then the vms on that host are restarted on another host with available resources within the cluster. Fault tolerance is similar except in this case continuous uptime is provided (no need for restarting on another host). basically a primary VM (the running main vm) sits on one host and a secondary vm sits on another host, so if the primary fails then the secondary immediately takes over. vMotion allows for the live migration of virtual machines from host to host, or live migration of virtual machine from storage medium to storage medium via Storage vMotion. Lets say I need to schedule maintenance of an host, I can simply vmotion the running vm off the host to another available host without downtime or loss of services to the enduser.

As a side note, these features will require the use of VMWare’s management known as vCenter allows for a centralized single pan of glass to manage host/resources and their associated virtual machines.

Virtualizing in the Data Center: As time has progressed, pricing and benefits have allowed and sometimes forced companies to move away from the on-premise model and into the data center. No longer is virtualization in the data center restricted to PC based hardware, Apple hardware has made it’s way into the datacenter realm in a big way over at MacStadium.

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