Upgrading a vSphere 8.x Environment to VMware Cloud Foundation 9.0 – Real-World Journey

The release of VMware Cloud Foundation (VCF) 9.0 marks a major shift in how modern private cloud platforms are engineered and managed. For organizations operating a vSphere 8.x environment, the path to VCF 9.0 introduces a more modular architecture, improved lifecycle management, stronger security baselines, and support for next-generation workloads.

This guide provides a deep, end-to-end walkthrough of the upgrade journey—from preparation and compatibility validation through the actual upgrade sequencing and post-upgrade verification. The goal is to help architects and administrators execute this transition confidently, with clarity on each critical step.

Why Move From vSphere 8.x to VCF 9.0

Although the vSphere 8.x setup was stable and well-structured—with multiple clusters operating reliably across compute-only hosts, vSAN-based nodes, and some NSX-integrated workloads—it still carried several limitations typical of a growing data centre. The environment functioned well day to day, but the underlying operational challenges signaled the need for a more unified and automated cloud platform.

• Lifecycle management tasks were still manual and time-consuming
• Host upgrades required extended maintenance windows
• Network configuration consistency differed across clusters
• Governance and policy enforcement weren’t unified
• Operational tooling was fragmented across different systems

At the same time, there was a clear goal to achieve:

• A private cloud experience aligned with hyperscaler standards
• Automated, streamlined operations
• Centralized lifecycle management for the entire stack
• A foundation ready for Kubernetes and modern application platforms

VCF 9.0 delivered exactly the kind of integrated, automated, and future-ready platform needed to address these requirements.

The First Step: Understanding What We’re Actually Changing

VCF 9.0 is not like “upgrading vCenter from 8.0 to 8.0U3.”
It’s a platform-level transformation.

When you transition from vanilla vSphere to VCF, three things change dramatically:

1. Your infrastructure becomes governed by a Fleet (VCF Fleet Management)

Everything — ESXi hosts, vCenter, NSX, vSAN, certificates, operations — begins to live under a unified lifecycle management engine.

2. Your management architecture gets an entire redesign

VCF 9 introduces Fleet, Operations, and Automation components that work together. This simplifies operations but changes how things are deployed and updated.

3. Your cluster upgrade model becomes image-based only

No more baselines.
No more VUM.
This was a big shift for the customer.

Understanding these changes helped set the right expectations before touching anything.

 

Pre-Upgrade Checklist: What I Checked (and Double-Checked)

I’ve done enough upgrades to know: 70% of failures happen due to missing prerequisites.

So here’s what I validated before even thinking of VCF:

 Hardware compatibility (HCL)

We confirmed:

• CPU family supported for ESXi 9.x
• NIC/FW/HBA firmware compatibility
• vSAN ESA readiness (for their vSAN-enabled clusters)

Networking: MTU, VLANs, TEP readiness

VCF 9 doesn’t enforce NSX overlay for every cluster, but if you want it, you need MTU 1600+.

Even if you don’t want overlay now — plan for it.

DNS, NTP, Certificates

VCF is extremely sensitive to:

• forward/reverse lookups,
• certificate mismatches,
• expired PSC/SSO certs.

Backup of all management components

Rule: If it boots, back it up.
vCenter, NSX Manager, Aria components — everything.

Operations tools version readiness

If the customer had older versions of:

• Aria Operations,
• Aria Operations for Logs,
• Aria Automation,

…they must be upgraded before joining the VCF 9 Fleet.

 Licensing

A surprisingly common delay.
We pre-validated VCF licenses before starting.

 

My Upgrade Strategy: Breaking It into Logical Phases

Instead of treating this as one giant upgrade, I approached it in four major phases:

Phase 1 — Stabilize and Upgrade the Existing vSphere 8.x Environment

This includes:

• Upgrading vCenter to a version supported by VCF Installer
• Making sure ESXi hosts are healthy
• Ensuring NSX Managers (if present) are compatible

For vCenter, I chose the “reduced downtime” upgrade path.
It creates a new appliance and copies over config — safer and cleaner.

For ESXi hosts, I started preparing the shift from baseline to image-based lifecycle, because VCF will enforce image compliance later anyway.

This phase established the foundation

Phase 2 — Upgrade or Deploy VCF Operations

This was the first moment where I really saw the shift from “vSphere admin” to “cloud admin.”

We had two options:

Option A: Upgrade existing Aria Suite to versions supported by VCF

or

Option B: Deploy VCF Operations fresh

We chose Option A because the I had existing dashboards and compliance packs I  wanted to retain.

A few notes from this phase:

• Operations upgrade pre-checks are extremely strict
• Old credentials stored in Aria can break registration workflows
• Time sync (NTP) must be perfect between all appliances

Once Aria was upgraded, we registered it properly with SDDC Manager.

 

Phase 3 — Deploy VCF Installer (The New Heart of Everything)

VCF 9 doesn’t use Cloud Builder. Instead, everything begins with the VCF Installer.

This step felt like “building a new control tower” while the airport is still active.

Steps I took:

1. Deployed the VCF Installer OVA

Simple enough, but ensure:

• DNS resolution is perfect
• IP addresses are reserved
• FQDN matches forward/reverse

2. Configured online/offline bundle access

I  had strict firewall restrictions, so we used:

• Offline bundle depot,
• Hosted on an internal web server.

This avoided internet dependency.

3. Connected Installer to the existing vSphere 8 environment

Here, we selected:

• Using the existing vCenter
• Using existing ESXi hosts
• Using upgraded Aria components

4. Performed pre-checks

VCF pre-checks are extensive.
They will catch:

• DNS mismatches
• MTU inconsistencies
• NTP drift
• Host hardware issues
• Missing drivers
• Certificate chain trust problems

I spent the most time here.

But honestly — fixing issues before deploying Fleet saved us hours later.

Phase 4 — Converging Into a VCF 9 Fleet

This was the most exciting part.

VCF Fleet Management discovers your environment and begins standardizing it.

The Installer automatically:

• creates the Fleet database,
• sets up SDDC Manager,
• registers Aria Operations & Logging,
• connects to vCenter,
• establishes governance,
• and prepares workload domains.

After this, the environment officially becomes VCF 9. It felt like everything clicked into place.

 

Post-Upgrade Work: What I Did to Finalize Everything

Upgrading isn't over until the environment is stable and integrated.

I focused on:

1. Verifying Fleet inventory

Checking that:

• hosts,
• clusters,
• vCenter,
• NSX Managers,
• Aria tools were all correctly discovered.

2. Validating image compliance

VCF now enforces image-based lifecycle. I created cluster images and remediated any drift.

3. Running operational sanity checks

• vMotion
• DRS behaviour
• vSAN health
• Host remediation testing
• Backup tool integration
• Logging ingestion

4. Re-validating integrations

• AD/LDAP
• Certificate authority
• Syslog
• Monitoring tools
• Backup vendors

5. Documenting everything

Always, always document:

• build versions
• IP/FQDN mapping
• upgrade decisions
• rollback plan
• cluster design
• lifecycle policy

This helps you as future admins.

What I Learned From This Upgrade

1. VCF 9 is not “just an upgrade” — it’s a platform transition

It changes how you operate your data center.

2. Lifecycle management becomes dramatically easier

Once Fleet is in place, upgrades feel like cloud updates.

3. Pre-checks decide your success

If pre-checks are green, the rest of the journey becomes smooth.

4. DNS, MTU, and certificates are the silent killers

Almost every deployment issue traces back to one of these.

6. Documentation gaps matter

I documented every decision, so the next person doesn’t struggle.

Upgrading from vSphere 8.x to VMware Cloud Foundation 9.0 is one of the most meaningful modernization steps you can take in a private cloud environment. It brings consistency, automation, lifecycle uniformity, and long-term stability.

But it’s not a “click next” upgrade.
It requires thoughtful planning, clear understanding, and methodical execution.

If you understand the journey, prepare thoroughly, and respect the dependencies, the upgrade becomes smooth — and honestly, rewarding.

I hope sharing it helps someone preparing for theirs.