This guide covers prerequisites, the step-by-step upgrade process, and troubleshooting tips for upgrading your vCenter Server Appliance (VCSA) from 7.x to 8.0.

1 Prerequisites

1.1 Compatibility & Environment Checks

• Use VMware’s Product Interoperability Matrix to confirm ESXi hosts, NSX/third-party plugins, backup/monitoring tools, and integrations support vSphere 8.0.
• Verify your hardware/software meets vCenter 8.0 Appliance requirements (CPU, RAM, disk).
• Synchronise NTP across all ESXi hosts and the VCSA to avoid certificate and SSO failures.

1.2 Source Appliance

• VCSA must be version 6.7 U3+ or 7.0.x. If earlier, upgrade to 7.0 first.
• Open ports on the source:
  • TCP 22 (SSH) for data export
  • TCP 443 (HTTPS) for API calls and health checks
• If you have an external Update Manager, run VMware Migration Assistant on its Windows server (manual for GUI, auto via JSON for CLI).
• Ensure at least 10 GB of free space on the VCSA root filesystem to accommodate snapshots and temporary files.
• Take a full image-based backup (or snapshot) of the VCSA and vPostgres database.
• For Enhanced Linked Mode (ELM): power off all linked vCenters, take synchronised snapshots, and on restore, revert all snapshots together.
• Set DRS automation on the source cluster to Manual or Partially Automated to prevent VMs (including VCSA) from moving mid-upgrade.

1.3 Target ESXi Host (or Cluster)

• Ensure the target ESXi is not in lockdown or maintenance mode and has connectivity to the source VCSA.
• Open TCP 443 and TCP 22 on the host’s firewall.
• If deploying to a DRS cluster, set Automation to Manual/Partially Automated.
• If using vSphere with Tanzu, pick a cluster without a running Supervisor control plane.

2 Upgrade Process

2.1 Preparation

1. Download the vCenter 8.0 ISO from VMware Customer Connect or the Broadcom Support Portal.
2. Mount the ISO on a machine with network access to the vSphere environment.
3. Reboot the source VCSA to clear pending reboots.
4. Disable vCenter HA (if enabled) via the VAMI or CLI.
5. Confirm snapshots/backups are valid.

2.2 Stage 1 – Deploy New Appliance

1. On your admin workstation, run:
   iso-drive:\vcsa-ui-installer\win32\installer.exe
2. Select Upgrade > Next.
3. Supply source VCSA FQDN/IP, SSO admin credentials, and ESXi/vCenter host for both source and target.
4. Configure the new appliance:
   • VM name, root password
   • Deployment size (Tiny, Small, Medium, Large)
   • Datastore, provisioning type (thin/thick)
   • Network port group, temporary IP/hostname
5. Review and Finish. The installer deploys a staging VCSA 8.0 alongside VCSA 7.x.

2.3 Stage 2 – Data Migration

1. The wizard runs pre-upgrade checks (certificates, DRS, network). Address any warnings/errors before proceeding.
2. Choose data retention level: Configuration only, Configuration + Historical, or Full (including performance data).
3. Acknowledge the backup confirmation and start migration.
4. Monitor progress. On completion, the old appliance is powered off, and the new VCSA inherits its identity (FQDN/IP).

2.4 Post-Upgrade Tasks

• Log in to the new VCSA VAMI: https://vcenter-fqdn:5480 to verify services.
• Check vSphere Client: confirm inventory, clusters, hosts, datastores, networking, alarms, and roles.
• Upgrade ESXi hosts to 8.0 via Lifecycle Manager.
• Update VMware Tools and virtual hardware on VMs.
• Re-enable vCenter HA if needed.
• Reapply DRS automation policies.
• Validate backup jobs, DRS/HA settings, and NSX/third-party plugin registrations.

3 Troubleshooting

3.1 Pre-Upgrade Failures

• Certificate SHA-1 warnings: vSphere 8.0 disallows SHA-1 certs. Replace them before the upgrade.
• DRS is fully automated: switch to manual or partial on source and target clusters.
• Insufficient disk space: clear logs or expand the datastore.

3.2 Installer & Firstboot Failures

• SSH into the new appliance. Generate support bundle:
• run: vc-support.sh
• Logs archive in /storage/log.
• Examine /var/log/firstboot/firstbootStatus.json and related script logs in /var/log/firstboot/.
• Review /var/log/vmware/vsphere-ui/logs/ and /var/log/vmware/applmgmt/ for service startup failures.

3.3 Networking & Firewall

• Ensure bi-directional connectivity on:
  • TCP 443 (vCenter ↔ ESXi, vSphere Client)
  • TCP 22 (SSH for migration)
  • TCP 5480 (VAMI)
  • UDP 123 (NTP)
  • TCP 902/903 (VM console, heartbeat)
• Confirm no ACLs or distributed firewall rules block these ports.

3.4 Validation & Recovery

• Use the vSphere Upgrade precheck log (vmware-vum-server-log4cpp.log) for scripted upgrades.
• If migration fails irrecoverably and no valid backup exists, redeploy VCSA 8.0 and restore from data-centre backup.
• Engage VMware KB and Community Forums for unique error codes.

Reference:
Prerequisites for Upgrading the vCenter Server Appliance