VMware has recently released its new VM hypervisor product, VMware ESXi 5.0. VMware is replacing its current ESX model with ESXi and the biggest change (between ESX and ESXi) is the architecture, as most of you VM gurus are well aware of, but for the people that don’t know I will quickly explain.
VMware ESX Architecture
In the original ESX architecture, the virtualization kernel (referred to as the vmkernel) is augmented with a management partition known as the console operating system (also known as COS or service console). The primary purpose of the Console OS is to provide a management interface into the host. Various VMware management agents are deployed in the Console OS, along with other infrastructure service agents (e.g. name service, time service, logging, etc). In this architecture, many customers deploy other agents from 3rd parties to provide particular functionality, such as hardware monitoring and system management. Furthermore, individual admin users log into the Console OS to run configuration and diagnostic commands and scripts.
VMware ESXi Architecture
In the ESXi architecture, the Console OS has been removed and all of the VMware agents run directly on the vmkernel. Infrastructure services are provided natively through modules included with the vmkernel. Other authorized 3rd party modules , such as hardware drivers and hardware monitoring components, can run in vmkernel as well. Only modules that have been digitally signed by VMware are allowed on the system, creating a tightly locked-down architecture. Preventing arbitrary code from running on the ESXi host greatly improves the security of the system.
For more information on differences or new features of ESXi 5.0 please go to the VMware website for more information.
The only requirements here are to go to the VMware website and download the VMware ESXi 5.0 Hypervisor ISO and the VMware vSphere 5.0 Client, you will need a VMware account for this if you don’t already have one.
Upgrade / Migration Procedure
Unlike my other tutorial which has a few steps to follow and you have to download individual upgrade files, VMware has made this quite an easy and hopefully painless process (saying this because sometimes upgrades are never perfect). The first thing we have to do is prepare your host server for the upgrade, so log into your host server via the vSphere Client, and shut down all your VMs, after that put the ESXi 5.0 CD into your host server and reboot the host. Make sure the host server is set to boot up off your CD/DVD drive or select it from a boot menu. The installer will load the required files and then boot the installation.
Now this is a text based installation just like the previous versions of ESXi installation, the first screen is your typical welcome screen and it gives you a link to the compatibility guide and VMware’s website. You will be prompted to read and agree to the EULA (End User License Agreeement); press F11 to continue. At this stage the installation will start scanning for available devices on your host server, it’s mainly hard drives and remote storage (iSCSI/NFS/SANs, etc.) we are concerned about here. Once the scan is finished and it displays available VMFS Partitions, select the partition that your current ESX / ESXi installation is on, as we want the installation to detect the install.
When you select the storage device a box will appear stating that it’s “Gathering Additional Information” – this is scanning for any previous installation of ESX / ESXi; once completed and it has deteceted your installation you will be given 3 options.
Force Migrate ESXi, Preserve VMFS Datastore: This will take your current installation and configuraiton and attempt an upgrade/migration and keep your VMFS Datastores intact, so your VMs will be preserved if things go wrong.
Install ESXi, Preserve VMFS Datastore: This will install a fresh copy of ESXi 5.0 and leave your VMFS datastores intact, this will erase all custom configurations, it’s a clean slate basically and you will have to re-add your VMs back to your inventory once you have reconfigured your host server.
Install ESXi, Overwrite VMFS Datastore: This does exactly what it sounds, it will install a clean copy of ESXi 5.0 and overwrite your current datastores – you will LOOSE all information on that datastore.
For this Tutorial we are going to select Force Migrate ESXi because we are attempting an upgrade and we want our configuration to stay. Once you press enter the installation will scan for your configuration, once that is complete you will be given a confirmation warning, Be warned you can not roll back your installation to ESX or ESXi 4 – it is not supported! Press F11 to continue.
This process can take a while depending on how big your host installation is, while you’re waiting why don’t you install the new vSphere Client you downloaded earlier, if you don’t install it, when you log onto your upgraded host server for the first time it will prompt you to download or run the installer (which still involves a download).
Once the upgrade is complete, you will be prompted to reboot the host server, it will also warn you that your installation has gone back to a trial verison; you must enter your ESXi 5.0 license key that you got with the iso once you log in with the vSphere Client.
That’s it, you’re done, enjoy your upgraded ESXi host, just remember to upgrade your VM’s hardware and VMware Tools installations.