Upgrading VMware ESXi hosts is a routine but critical task for virtualization administrators. While ESXi upgrades are generally reliable, configuration loss or misconfiguration can quickly turn a planned maintenance window into an outage.
Backing up your ESXi host configuration before every upgrade is a simple but essential best practice. This article walks through why configuration backups matter, how to back up ESXi configs, and how to restore them if something goes wrong.
Why Back Up ESXi Configurations?
An ESXi configuration backup captures important host settings such as:
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Network configuration (vSwitches, port groups, VLANs)
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VMkernel interfaces (management, vMotion, storage)
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Storage configuration
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Advanced system settings
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Licensing information
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Authentication and security settings
If an upgrade fails or a host needs to be rebuilt, restoring the configuration can save hours—or even days—of manual reconfiguration.
When Should You Back Up?
You should back up ESXi configurations:
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Before upgrading ESXi
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Before applying patches
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Before major network or storage changes
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As part of regular maintenance
💡 Tip: Make ESXi config backups part of your standard change-management checklist.
Method 1: Backup ESXi Configuration Using vSphere CLI (esxcli)
This is the most common and reliable method.
Step 1: Enable SSH on ESXi Host
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Log in to the ESXi Host Client
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Go to Manage → Services
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Start SSH
Step 2: Run the Backup Command
Connect to the ESXi host via SSH and run:
vim-cmd hostsvc/firmware/backup_config
Step 3: Download the Backup File
The command generates a backup bundle stored in:
/scratch/downloads/
Download the .tgz file to a secure location (for example, a backup server or admin workstation).
📁 Example filename:
configBundle-ESXiHost.tgz
Method 2: Backup ESXi Configuration Using PowerCLI
PowerCLI is ideal when managing multiple ESXi hosts.
Step 1: Connect to vCenter or ESXi
Connect-VIServer vcenter.company.local
Step 2: Export Host Configuration
Get-VMHost ESXi01 | Get-VMHostFirmware -BackupConfiguration -DestinationPath C:\ESXi_Backups
✔ This method automatically downloads the backup file
✔ Great for scheduled or bulk backups
Method 3: Backup via vCenter Auto Deploy (Stateless Hosts)
If you’re using stateless ESXi hosts, host profiles and Auto Deploy handle configuration persistence. However, you should still:
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Export Host Profiles
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Backup vCenter Server
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Document networking and storage dependencies
How to Restore ESXi Configuration
If an upgrade fails or the host needs to be reinstalled, restoring the configuration is straightforward.
Step 1: Reinstall ESXi (If Required)
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Use the same ESXi version as the backup
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Ensure the host name matches the original
Step 2: Restore Configuration Using CLI
Upload the previously backed-up .tgz file to the ESXi host and run:
vim-cmd hostsvc/firmware/restore_config /vmfs/volumes/datastore1/configBundle.tgz
The host will automatically reboot and apply the configuration.
Restore Using PowerCLI
Set-VMHostFirmware -VMHost ESXi01 -Restore -SourcePath C:\ESXi_Backups\configBundle.tgz
✔ Faster and safer for remote recovery
✔ Ideal for scripted disaster recovery
Post-Restore Validation Checklist
After restoring, always verify:
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Management network connectivity
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vSwitch and VLAN configuration
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VMkernel interfaces
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Datastore visibility
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Host licensing
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vCenter connectivity
Best Practices for ESXi Configuration Backups
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🔐 Store backups in a secure, off-host location
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🗂 Name backups clearly (host + date)
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🔄 Automate backups using PowerCLI
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📄 Document critical host settings
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🧪 Test restore procedures periodically
Backing up ESXi configurations before upgrades is a low-effort task with high payoff. Whether you manage a single host or a large vSphere environment, having a recent configuration backup ensures you can recover quickly and confidently from upgrade failures.
Never upgrade ESXi without a backup—it’s your safety net.