# Upgrade ESXi 8 to 9.1: Safe esxcli and Lifecycle Manager Steps

Source: https://srvscripts.com/guides/upgrade-esxi-8-to-9/
Updated: 2026-10-03
Publisher: srvScripts (https://srvscripts.com/)

In short: Upgrade vCenter to 9.1 first, confirm each host’s hardware against the compatibility guide and run the pre-check, then either put the host in maintenance mode and run esxcli software profile update -d…

ESXi 9.1.1.0 shipped in early September 2026 and is the release most teams will target for the move off the 8.0 line, whose current build is 8.0 U3k from July 2026. The upgrade path from 8.0 U3 is direct, but 9.x drops support for some older hardware, removes legacy VIBs and locally attached storage controllers that were already deprecated in 8, and requires vCenter 9 before hosts are upgraded. This guide covers the two supported methods: a manual esxcli upgrade for standalone hosts or small clusters, and vSphere Lifecycle Manager images for clusters managed by vCenter 9.1.

**Short answer:** Upgrade vCenter to 9.1 first, confirm each host’s hardware against the compatibility guide and run the pre-check, then either put the host in maintenance mode and run `esxcli software profile update -d /vmfs/volumes/datastore1/VMware-ESXi-9.1.1.0-depot.zip -p <profile-name>` from the offline bundle, or in vCenter define a cluster image with the 9.1.1 base, the vendor add-on and firmware, run a compliance check and remediate. Reboot, verify with `vmware -vl`, and keep the previous bootbank available for rollback until the host has run cleanly for a few days.

## Pre-flight checks

- vCenter must already be at 9.x; see [Upgrade vCenter Server Appliance 8.0 to 9.x](/guides/upgrade-vcenter-8-to-9/).

- Check CPU support. ESXi 9 raises the minimum CPU generation and removes some older Intel and AMD families; the installer refuses unsupported CPUs unless you accept the override, and support is not guaranteed afterwards.

- Boot device. ESXi 9 requires a persistent boot device with room for the consolidated ESX-OSData partition; SD cards and USB sticks as the only boot device are not supported. Check with `esxcli storage core device list` and `ls /vmfs/volumes/ | grep OSDATA`.

- Third-party VIBs. List anything not from VMware and confirm a 9.x version exists:

```
esxcli software vib list | grep -v -i "VMware\|VMW"
esxcli software vib list --rebootless
```

Drivers with no 9.x build will block the upgrade with a dependency error; remove them first with `esxcli software vib remove -n <name>` if the hardware they serve is no longer present.

- Free space on the boot device (`vdf -h`) and a recent configuration backup: run `vim-cmd hostsvc/firmware/backup_config` and download the resulting tarball from the URL it prints, or export a host profile from vCenter.

## Method one: esxcli from an offline bundle

Upload the ESXi 9.1.1.0 offline bundle (or the OEM-customised bundle for your server vendor) to a datastore, enter maintenance mode, and list the profiles it contains:

```
esxcli system maintenanceMode set --enable true
esxcli software sources profile list -d /vmfs/volumes/datastore1/VMware-ESXi-9.1.1.0-depot.zip
```

Pick the “standard” profile (includes VMware Tools) unless space is tight, then perform the upgrade with `profile update`, which keeps newer third-party VIBs, rather than `profile install`, which replaces everything:

```
esxcli software profile update -d /vmfs/volumes/datastore1/VMware-ESXi-9.1.1.0-depot.zip -p ESXi-9.1.1.0-standard
```

Read the output: it lists VIBs installed, removed and skipped, and ends with “Reboot Required: true”. If it stops with a hardware or dependency error, resolve it rather than adding `--no-hardware-warning` on a production host. Then reboot:

```
reboot
```

## Method two: vSphere Lifecycle Manager image

In vCenter 9.1 select the cluster » Updates » Image. If the cluster still uses baselines, convert it to an image (one-way). Define the image: ESXi version 9.1.1.0, the vendor add-on matching your servers, the firmware and drivers add-on if the hardware support manager is registered, and any additional components. Save, then run Check compliance and Run pre-check; the pre-check flags hardware, VIB and DRS issues per host before anything changes.

Remediate the cluster or one host at a time. Lifecycle Manager places each host in maintenance mode, evacuates VMs with DRS, installs the image, reboots, and moves on. Set the remediation options to skip hosts that fail rather than abort the whole run, and watch the first host through to completion before letting it continue.

## Verify

On each upgraded host:

```
vmware -vl
esxcli software profile get
esxcli system version get
esxcli storage core adapter list
esxcli network nic list
```

Confirm the build string, that all HBAs and NICs are present with the expected driver, and that datastores are mounted. In vCenter check the host shows compliant with the image and that VMware Tools status on guests is current or supported. Exit maintenance mode and let DRS rebalance.

## Common pitfall

Upgrading a host before vCenter is the classic mistake; a 9.1 host cannot be managed by vCenter 8 and drops off the inventory until vCenter is upgraded. The second most common is an unsupported NIC or RAID driver whose VIB is silently removed during the upgrade, leaving the host without its storage on reboot. The esxcli output and the Lifecycle Manager pre-check both list removed VIBs; read them.

## Upgrade ESXi 8 to 9 at a glance

**Official documentation:** [Broadcom TechDocs (VMware)](https://techdocs.broadcom.com/), [Linux man pages](https://man7.org/linux/man-pages/).

**Related guides:** [Migrate VMs from VMware to Proxmox VE 9 after the Broadcom licensing changes](https://srvscripts.com/guides/migrate-vmware-to-proxmox-ve-9/) · [Convert a physical Windows Server to a VMware VM (P2V) in 2026](https://srvscripts.com/guides/p2v-windows-server-vmware/) · [Upgrade vCenter Server Appliance 8.0 to 9.x with the Migration Assistant](https://srvscripts.com/guides/upgrade-vcenter-8-to-9/).

## Frequently asked questions

### Does the upgrade path from ESXi 7.0 to 9.1 work directly?

No. ESXi 7.0 must first go to 8.0 U3, and then to 9.x. Attempting to apply the 9.1 bundle to a 7.0 host fails the profile update with an unsupported upgrade path error.

### How long does an ESXi host upgrade take?

The esxcli update itself runs in five to ten minutes plus one reboot, which on enterprise servers with long POST times can add another ten. Lifecycle Manager adds the VM evacuation time per host, so plan around 30 minutes per host in a busy cluster.

### Can I roll back to ESXi 8.0 U3 after upgrading?

Yes, until the host is upgraded again. Reboot and press Shift+R at the boot loader to select the previous bootbank; the host returns to the 8.0 U3 build with its previous configuration. Any change made under 9.1 is lost.