Upgrade plan for vSphere version 8.0U2

Check Product Interoperability Matrix https://interopmatrix.vmware.com/Interoperability

It’s essential to make sure that any components should support vSphere 8.0 U2; for example:

Backup solution
Replication solution
Monitoring tool
Hardware Firmware
BIOS
Cisco EPG ACI
VMware Tools
NSX
vSAN
Host Profiles
Any third-party VIB installed
Any non-VMware software
(Consult with the respective vendors to ensure that they are compatible with version 8.0 of vSphere or not)

Have backups been performed on all components being upgraded? (All the VMs, ESXi Configuration “Host Profiles”, Distributed Virtual Switches, vCenter Appliance “by using the built-in File-Based Backup”, and other VMware products like: NSX or Horizon).
Has time been verified on all hosts in the environment?
The current version of vDS (if used, vCenter version 8.0 requires all vDS to be on version 6.5.0 “minimum supported version” or later)?
Is there sufficient storage space and free computing resources for the upgrade?
If an environment is not in a healthy state, errors can occur that may require a rollback; Common mistakes that could cause a failure may be invalid DNS or NTP settings, hard disk capacity, or the possibility of a critical service that may have stopped, and the reason is to prevent further errors from occurring.
Upgrading Distributed Switch sometimes requires downtime for all the hosts and VMs connected to the same vDS.
Upgrade vCenter and ESXi licenses to version 8.

VMware tools: the minimum supported version must be 10.3.0; before upgrading vCenter to 8.0U2

Minimum ESXi version 6.7 (for direct upgrade to 8.0)
Hardware has been verified against the VMware compatibility guide
Products compatibility matrix has been validated for software
Minimum vCenter Server version 6.7 (for direct upgrade to 8.0)
vCenter Server - Verify the required ports are open to/from the vCenter Server system
vCenter Server - Verify that the time is synchronized for the vCenter Server host and all other components being upgraded
vCenter Server - Verify the required ports are open to/from the vCenter Server system
ESXi Hosts - Review the ESXi host alerts, alarms, and log files for any issues that should be resolved before upgrading to ESXi 8.0
ESXi Hosts - Backup and document the ESXi host configuration
ESXi Hosts - Ensure the LUN does not have a VMFS partition in SAN
ESXi Hosts - A boot disk of at least 32 GB of persistent storage
ESXi Hosts - A boot device must not be shared between ESXi hosts
ESXi Hosts - The NX/XD bit must be enabled for the CPU in the BIOS
ESXi Hosts - To support 64-bit virtual machines, support for hardware virtualization (Intel VT-x or AMD RVI) must be enabled on x64 CPUs

It’s recommended to engage an engineer for each scope of this activity:

This activity has three phases that comprise the upgrade process:

Phase 1: Pre-Upgrade: Environment discovery and assessment activities to complete prior to upgrading:
Includes the key information to be reviewed prior to beginning the upgrade process: Discover all components and their associated current version and upgrade version, Product Release Notes, Product Documentation, Interoperability Matrices, and the VMware Compatibility Guide, and Multi-Cloud solution, and validation of doing an in-place upgrade between supported versions. It is also important to understand what is involved to perform a rollback in the event of an upgrade issue.
Phase 2: Upgrade: Identifying all components and mapping out the step-by-step upgrade process
Phase 3: Post-Upgrade: Activities to complete after completing an upgrade

Phase 1: Pre-Upgrade:

Before the upgrade, please check these prerequisite checklists:

Prerequisite checklists	Status:
Check VMware Compatibility Guide & VMware Product Interoperability Matrix to verify physical hardware compatibility and the integration between VMware products (check server model and CPU and recommended BIOS for specific update) (check storage/SAN drivers and firmware)
It’s recommended to deploy the customized ESXi from the vendor of the physical host.
Make sure the version of VCSA is equal to or higher than ESXi
Check physical hardware vendor corresponding compatibility matrix
Verify that you have sufficient disk space for upgrading the ESXi hosts.
Check whether enough resources are available in the ESXi hosts part of the cluster to migrate virtual machines.
Verify the compatibility of the network card (NICs), storage I/O controller (HBA), storage device/array, backup software, and hardware BIOS firmware, drivers, and partner vendor’s software vibs.
Verify that you have backed up the virtual machines.
Use Distributed Resource Scheduler (DRS) to prevent virtual machine downtime during the upgrade. Verify that the automation level for each virtual machine is set to Fully Automated mode to help DRS migrate virtual machines when hosts are entering maintenance mode.
Are licenses available for vSphere 7.0 and 8.0?
Has time been verified on all hosts in the environment?

Phase 2: Upgrade:

For the upgrade plan, here are the tasks:

Tasks	Status
Place the host that you intend to upgrade in maintenance mode.
Import the ISO and files to update manager
Create custom baseline " choose the updates that you have downloaded "
Attach baseline to required ESXi " choose baseline type based on what you want "
Click on Scan for Updates " specify whether you want to scan only for patches or for upgrades or both "
Click on Check Compliance " check the host compliance status “Non-Complaint” means that host can be upgraded or needed patches. If it is “Complaint” – host is running with latest version and patches then the baseline "
Click on Pre check Remediation on the ESXi " verify conditions and identify possible problems that may occur after remediating, like: you may need to disable DPM, HA admission control, and enable DRS, or need to disconnect a virtual DVD drive, disable Fault Tolerance for the VM in a cluster”
Click on Stage Patches " Which means all the Patches or Upgrades will be copied to ESXi host so that patching can be performed quickly "
Click remediate to apply remediation "ESXi hosts enter the maintenance mode automatically when remediating. When remediation is done, ESXi hosts exit the maintenance mode, and a host reboot may be required."
You must manually restart your ESXi host from the vSphere Client.
Exit maintenance mode.

Phase 3: Post-Upgrade:

The next step is to perform “Day 2 operations,” ensuring that you have an optimal vSphere experience:

Tasks	Status
After the remediate is completed in the task bar, the host will be have Compliance Status as “Complaint”.
Verify the ESXi is updated by checking build number and version " check the status of the Host & check for all the storage devices which are presented & other configuration if any "
Verify that everything is working properly
Optional \| Renew certificates if the environment has been running for several years, the expiry of SSL/TLS certificates may be approaching; by renewing the certificates will reset the clock for another two years.

Rollback plan (In case you faced an unresolvable issue):

Place the host that you want to downgrade in maintenance mode
Open DCUI via SSH or direct console or console over IP
Hit F12, then hit F11 to restart the host
Once ESXi begins to load, hit Shift+R to access Recovery Mode
Select Y to roll back " once this procedure is carried out, you won’t be able to go back to the upgraded version other than by installing it again "
Verify the correct version has loaded.
Navigate back to vCenter. If the host did not re-connect, manually Connect the host.
Then Exit Maintenance Mode