I've been doing a lot of upgrading and migrating recently, and I've started to compile general questions I need to ask myself or clients before doing any upgrades, especially VMware product upgrades. Here's my list of five questions that I go over before doing a VMware upgrade. (Note: This post is a supplement, not a substitute, for VMware's upgrade guides.)
What VMware products do you have?If you're only running vSphere on vCenter, then your upgrade preparation will be a bit simpler than if you're also running VMware View. If you're also running VMware View, you should check for compatibility. When vSphere 5.1 first came out, it was not compatible with VMware View 5.1, so you wanted to avoid upgrading right away. You should check the VMware Product Interoperability Matrix (Figure A) to try to sidestep such issues. Figure A
VMware Product Interoperability Matrix (Click the image to enlarge.)
Which versions of the Windows OS and databases are you using?
Prior to vSphere 5, it was acceptable to use Windows 2003 32-bit; however, vCenter now requires a 64-bit Windows operating system, preferably Windows 2008 R2. VMware View will still work with Windows 2003 standard, but it will not give you the best performance. For the View connection server, Windows 2008 R2 is highly recommended with 10 GB of memory.
You'll also want to use the check the versions of the databases you're using via the VMware Product Interoperability Matrix. If you're still using an older version of Windows, you'll first want to figure out how to upgrade or possibly migrate them.
What problems do I need to correct before upgrading?
Before you even think about upgrading, you'll want to correct any problems you're having. This is also a good time to correct any poorly configured aspects of your environment.
A good plan is to run RVTools to see if you can find any issues. For instance, if you're using a Virtual Standard Switch, are all of your networks on all the hosts named the same thing (remember, case size matters)? Do you have network redundancy on all your vSwitches? You may also want to check your physical network switches to make sure the ports are configured properly. You should make sure DNS is configured correctly, and that it is the same for all hosts in the cluster. You can glean a ton of information from RVTools and other such utilities.
Are you adding new physical servers to the environment or migrating your virtual machines to the new servers?
You'll want to check the EVC mode. You cannot do vMotions between hosts if they have different processors, even if they're in the same cluster. You can get around this by enabling EVC and setting it to the lowest common processor. You may lose some features of the newer processors, but this will allow you to vMotion between all the physical hosts.
There is a caveat: In order to enable EVC and put the hosts in a different mode, you need to power off any virtual machines on those hosts. It's probably best to turn EVC on before you put any production virtual machines on them.
Do I have the necessary credentials?
You'll want to make sure you have the necessary credentials, especially if you didn't initially set the environment up. You may need access to the physical switches (networking and storage), SQL servers and databases, the SAN, the ESXi hosts, vCenter, and DNS and Active Directory. You can probably get away with just knowing the ESXi and vCenter credentials for a simple vSphere upgrade, but you will not be able to configure your environment in the best way possible without access to these other things.
There are many other things you need to consider before moving ahead with an upgrade, but I hope these items will get you thinking about all of the elements that go into your environment and what upgrades require.
What do you always check before performing a VMware product upgrade or a general upgrade? Let me know what you would add to this list by posting your comments in the discussion.
Lauren Malhoit has been in the IT field for over 10 years and has acquired several data center certifications. She's currently a Technology Evangelist for Cisco focusing on ACI and Nexus 9000. She has been writing for a few years for TechRepublic, Tech Pro Research, and VirtualizationAdmin.com. As a Cisco Champion, EMC Elect, VMware vExpert, and PernixPro, Lauren stays involved in the IT community. Lauren has been a delegate for Tech Field Day and has also authored a book called VMware vCenter Operations Manager Essentials.