A host of new features highlighted the latest version of vSphere but VMware also gave its core hypervisor platform...
an upgrade. ESXi 6.5 offers new security features, including Signed ISO Images and ESXi Host Secure Boot, and VMware Tools for commonly used guests OSes. The process of upgrading to ESXi 6.5 from versions 5.5 or 6.0 can be somewhat counterintuitive, so here's how to upgrade with minimal fuss.
Keep in mind that the ESXi upgrade does not support all devices; the VMware Knowledge Base offers a comprehensive list of these depreciated and unsupported devices. If you intend to use any plug-ins you should first make certain that they're supported by ESXi 6.5. I also recommend disabling plug-ins during the upgrade, then updating once the upgrade is complete.
At a high level, the upgrade creates a new vCenter with temporary networking and login details that the administrator configures. Once the temporary vCenter is deployed, ESXi 6.5 imports data from the source vCenter to the temporary vCenter, which is then rebooted. At this point, the temporary node assumes the identity and role of the original vCenter.
You need to upgrade the single sign-on (SSO) before you can upgrade vCenter. This process is relatively straightforward in environments where there is an embedded SSO server in use. Depending on your configuration, you may need to split the upgrade, performing the SSO infrastructure upgrade first. In larger environments, you will need to complete the SSO update globally before upgrading vCenter installations.
If necessary, consult VMware Professional Services before upgrading vCenter and the ESXi hosts. One of the interesting features with ESXi 6.5 is that it's now possible to upgrade the environment using a Windows PC, Mac or Linux workstation. For the sake of simplicity, I will use the Windows installer; for the purpose of this article, let's assume that you have already downloaded the vCenter upgrade and have mounted it as a CD volume.
Setting up the new vCenter for migration
Using Windows Explorer, navigate to the vcsa-ui-installer, win32 folder and double-click the installer application. Select the Upgrade option and there will be a two-stage dialogue representing the stages of the ESXi upgrade; click Next. Then, accept the license terms and click Next again.
On the next page, shown in Figure A, under the section titled Source appliance, enter the details of your current vCenter so that it can gather all of the data.
The next step, however, is where things get a bit tricky. Under the section titled ESXi host or vCenter Server that manages the source appliance, enter the details for the ESXi host on which the vCenter sits. If you don't perform this step correctly, the deployment will fail, preventing you from upgrading vCenter.
If prompted by the installation routine, accept the certificate by selecting Yes. In a simple environment, it's the ESXi host you need to use, not the vCenter.
The next step, shown in Figure B, is to give the temporary server a name and password to use for the duration of the upgrade. Once you've done this, click Next.
At this point, choose the appropriate setting for the size. Then, select which data store to use. On the penultimate page, as seen in Figure C, you need to configure the temporary vCenter for temporary IP details.
The final page is a confirmation page. If all the information is correct, click Finish. At this point, the initial first step is complete. The installer will deploy a new copy of the vCenter. This operation will take some time. The next step is to commit to the copy procedure.
Performing the migration
Going forward, the migration should be a fairly straightforward exercise. However, I advise setting the Distributed Resource Scheduler for the cluster to normal for the duration of the update.
The system will perform a pre-upgrade check. If you receive an error message, it's likely because you didn't read the important note about using hosts rather than vCenters.
Once the deployment is complete, click Continue.
The system will complete a series of pre-checks at the beginning of the second stage of installation. You may receive a warning saying the ESXi host is managed by vCenter Server, but you can safely ignore this.
Once the initial pre-checks are complete, the installer will give you a set of options regarding what data you wish to copy over. By default, it just does the configuration. If you need past events and performance metrics, select the appropriate choice from the menu.
The next page will invite you to join the customer experience program and provide diagnostics to VMware.
As shown in Figure E, the final stage of the ESXi upgrade wizard will present you with a summary. Be sure to double-check all of the settings; if you are happy with them, click the button to confirm that you've made a backup of the system in the event that anything bad happens during the upgrade and then click Finish.
You may receive a warning message saying the source vCenter will shut down once the upgrade is complete, but don't worry, as this is part of the plan.
After the initial data copy is complete, the system will set up the services and finally allow you to log in by clicking the URL on the completion page. Be patient, this will take a while to complete.
Verify the upgrade version by selecting the vCenter and clicking on the summary page. You should see the vCenter is upgraded, as shown in Figure F.
Your ESXi 6.5 upgrade is now complete. At this point, you should license the vCenter with version 6.5 licenses and upgrade the hosts. We'll cover how to do this using the newly included vSphere Update Manager within the appliance in a future article.
VSphere 6.5 among the biggest VMware topics in 2016
Some pleasant surprises to be found in vSphere 6.5
Seven steps for upgrading hosts from ESX to ESXi