While this blog is designed to be specific to EMC VNX and VMware vSphere, I have decided to dig a little bit into the basics of VMware, how we manage it, how we work on it, and generally just how your daily life works in a VMware environment. Of course as always your mileage may vary, but this is to give those new to the product a little bit of confidence in what they just paid for, and hopefully to take some of the fear and mystery out of VMware. This originally started on my other blog, but I am going to be using this one more often, so part 1 is just a re-post.
Having worked with VMware since ESX version 2, sometimes I forget that not everyone speaks the lingo, and is obsessed with every feature of vSphere. This realization came when a client, whom I consider a good friend, asked me for some training on how high availability works, and how to vMotion a virtual server. In light of this I have realized the time has come to write a series on the fundamentals of VMware. This will be part 1 of many, I plan to continue to write until I run out of topics.
So to start with we need to look at the layout of vSphere. vSphere is configured in a hierarchical layout similar to the following.
Virtual Center or vCenter, controls the cluster. This may be a physical host, but more often than not it will be a virtual machine riding ontop of one of the hosts it manages. This allows it to take advantage of the high availability features in VMware. In our logical layout, this is the top level object in the virtualization hierarchy.
Next down is the virtual datacenter. This is simply a logical representation of the datacenter. Think of it similar to how you might have 1 or more datacenters within a corporation.
Next is the Cluster. This is a bit of a new concept in the IT world, we are used to clusters which might have a couple servers in it, but they are typically application specific. In the case of vSphere, we are actually grouping a number hosts physically together to create a pool of shared resources.
Under this we have the hosts and virtual machines. At a logical level these appear in the same level, they are both members of the cluster, but of course physically the virtual machine lives on one physical host or another. The virtual machine is nothing more than a series of files, a configuration file, a disk file, and a few others. This enables us to do some cool things like move the virtual server between hosts without interrupting normal operations.
So that about covers the basics, next I plan to cover vMotion, and then possibly get deeper into the networking layout and storage layouts. If you have specific questions, please feel free to reply to this thread.