As a VMware Support and Subscription (SnS) customer, you need to upgrade before September 19th to avoid losing the full protection of a supported vSphere platform.
"You're right, we need to upgrade... But what does that all entail?". The vSphere platform has a very specific upgrade path you need to follow to ensure no service interruptions during the process. Before we dive into the VMware aspects, there are other variables to consider. Let's start with the host servers; the hardware ESXi calls home. Validate that the hardware is compatible with the version of ESXi you are upgrading to via the VMware Compatibility Guide. Take a look at host BIOS and firmware as well. The host hardware vendor may also provided information about compatible versions of ESXi on their website.
Even in the event that the existing BIOS and firmware is compatible with ESXi 6.0 or higher, now is a great time to upgrade. This helps to keep your hardware secure and up to the manufacturers recommended levels. One of the first things the vendor's tech support engineer is going to tell you to do is to upgrade the BIOS to troubleshoot any problems you may call in with. I know this from many calls to *insert hardware vendor here*.
So the host hardware is taken care of, what's next? Think about other systems that interact with vSphere. Is your storage platform compatible? What about your backup solution? Are there any vCenter plugins in use? Potentially many systems could be impacted by a VMware upgrade that's not properly planned.
"Alright, the hardware and peripheral systems are ready to go, time to move on to VMware!". Well, almost. Before diving into upgrading vSphere, take inventory of what vSphere editions and VMware programs you have deployed in your environment. Certain versions of vSphere and vCenter Server cannot be upgraded directly to 6.5+, so be sure to check the VMware Product Interoperability Upgrade Matrix first.
|vCenter Upgrade Path taken from kb.vmware.com|
It's worth noting that hosts are upgraded AFTER vCenter. Older versions of ESXi can connect to newer vCenters, but it does not work the other way around. I have encountered many people in my days attending VMUG meetings where they were unaware of this requirement and upgraded the hosts first.
One more thought on vSphere upgrades: in-place versus a clean install. I'm not going to tell you which way is best. Everyone has their own options and experiences. What I will say is that, from my experiences, in place upgrades to vSphere 6.5 have been successful. I've encountered some issues going from 5.5 to 6.0, mainly around Site Recovery Manager, but 6.0 to 6.5 appears to be more stable than in place upgrades past. (Again, this is my experience, your may vary.)
Finally, be sure to have backups before upgrading your environment and read the release notes for each product before proceeding. Watch out for any known issues that may trip you up during your upgrade or daily operations.
The key to a successful vSphere upgrade is planning. With the clock ticking on ESXi 5.5, you need to start planning as soon as possible to ensure a smooth transition and to stay protected.
End of General Support for vSphere 5.5 (51491)
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If you'd like to continue the conversation about vSphere upgrades, do not hesitate to contact me via any of the channels provided below. Do you have an idea or a topic for the blog? Would you like to be a guest on the ExploreVM podcast? If so, please contact me on Twitter, Email, or Facebook.