A VMware vSphere upgrade can test your resourcefulness, time management and stick-to-itiveness. Use the VMware Compatibility Guide, multiple versions of VMware Converter and some common sense to make the vSphere upgrade process easier and more successful.
Everyone in IT knows that time and money are very finite resources, and plenty have felt pain in their vSphere 5.1 upgrades. Often we have to make do with what's available and make it perform better and more securely than we thought was possible. During my vSphere upgrade, I was in the middle of a time crunch and had to upgrade multiple locations while juggling other IT priorities. These lessons learned during the vSphere update process will help in future upgrades.
Have an upgrade plan
It is easy to dive enthusiastically into an upgrade process. Beware: Without a solid vSphere upgrade plan, you could run around in circles or suffer through a hurry-up-and-wait period while resources are procured or support arrangements are made. The VMware Compatibility Guide proved valuable for verifying hardware and software compatibilities, as well as potentially unsupported configurations, in advance.
Outside of the data center checklist, be sure all the paperwork required for a major upgrade is sorted out in the beginning. I created physical diagrams of the current vSphere infrastructure and how I wanted it to look when complete. With this final objective in mind and clearly mapped out on paper, decisions are quick and effective during the vSphere upgrade process, especially when the going gets tough.
Be flexible about the upgrade path
The going will, in all likelihood, get tough. Having a plan for how you are going to arrive at your final infrastructure layout is essential, but it is no guarantee of a smooth ride. There are always potholes along the way, and factors we didn't consider. Stay flexible and adaptable. If something gets in the upgrade's way, don't let it stop all progress. Even if the workaround is not a perfectly elegant solution, it will keep your momentum going forward, and this will help complete the vSphere upgrade on schedule.
Remember that different tool versions work differently
In the process of various physical-to-virtual (P2V) and virtual-to-virtual (V2V) migrations, I found that each version of VMware Converter performed differently. Some versions were better suited for certain upgrade scenarios, and the time to complete migrations varied wildly based on several factors. VMware offers the last two major versions of Converter on its website. However, in one particular instance, neither version worked for the task at hand. I still had a very old version of Converter stored on CD; that turned out to be just what was needed. The conversion succeeded, and I was able to move forward with the upgrade.
A fresh mind is IT's friend
Everyone in IT has put in their share of 20-hour work days. Do you recall what starts to happen around hour 15? We get punchy and make a lot of mistakes, but press on, thinking "If I can just get X and Y to work, I'll be done. Then I can eat something that does not look like frozen cardboard and get a full night's rest." Working on a mentally taxing project like a vSphere upgrade will practically guarantee simple mistakes that take hours to resolve. If you're exhausted, the upgrade work is a complete waste of time. You will actually lose progress.
During this upgrade, after working for about 15 hours, I mistyped one character in a DNS record for an ESXi host. Later, we had intermittent problems with virtual machines going offline, host authentication problems and even some odd SSL errors. What could it be? I only resolved the problem once I retraced all my steps to get to the DNS record. With a good night's sleep, I likely would not have made that careless error and lost many valuable hours fixing it.
Ultimately, I completed this vSphere upgrade successfully and our virtual infrastructure is much better for it. I consider the lessons learned along the way to be at least as valuable -- if not more -- than the upgrade itself.