How to Upgrade from VMware ESXi 7 to ESXi 8: Three Reliable Methods Explained

VMware ESXi remains one of the most widely used hypervisors for building and managing virtualized environments. With the release of ESXi 8, VMware introduced significant improvements in performance, security, hardware compatibility, and lifecycle management. Organizations looking to modernize their virtualization infrastructure can benefit from upgrading their existing ESXi 7 hosts to the latest version.

However, a successful upgrade requires careful planning and execution. Upgrading a production virtualization platform without proper preparation can lead to unexpected downtime, compatibility issues, or even data loss.

In this guide, we’ll walk through the prerequisites for upgrading ESXi 7 to ESXi 8 and explore three proven upgrade methods:

• Upgrading using the ESXi ISO image
• Upgrading through the ESXi command line
• Upgrading with vSphere Lifecycle Manager

By understanding the advantages of each approach, you can choose the upgrade method that best suits your environment.

Why Upgrade to ESXi 8?

Before starting the upgrade process, it’s important to understand the benefits of moving to ESXi 8.

Some of the key improvements include:

• Enhanced performance for modern workloads
• Improved hardware support
• Better lifecycle management capabilities
• Increased security features
• Optimized resource utilization
• Improved support for Kubernetes and cloud-native applications
• Better integration with modern VMware solutions

Organizations running older virtualization environments can improve stability and gain access to new VMware features by upgrading to ESXi 8.

Important Pre-Upgrade Considerations

Before performing any upgrade, take time to verify that your infrastructure is ready.

Verify Hardware Compatibility

Not all servers that support ESXi 7 are compatible with ESXi 8.

Review VMware’s Hardware Compatibility List (HCL) and confirm that your:

• Server model
• Processors
• Storage controllers
• Network adapters
• RAID controllers

are officially supported.

Upgrade vCenter Server First

One of the most important VMware best practices is upgrading vCenter Server before upgrading ESXi hosts.

VMware recommends maintaining compatibility between vCenter and managed hosts. Attempting to upgrade hosts before updating vCenter can result in:

• Management issues
• Feature incompatibilities
• Host communication failures
• Potential service disruptions

Always ensure vCenter Server is running a supported version before proceeding.

Create Reliable Backups

Even though ESXi upgrades are generally straightforward, unexpected issues can occur.

Before upgrading:

• Backup virtual machines
• Export ESXi host configurations
• Create snapshots where appropriate
• Verify recovery procedures

Having a rollback plan can significantly reduce risk.

Check Available Resources

Confirm that sufficient:

• CPU resources
• Storage capacity
• Memory
• Maintenance windows

are available for the upgrade process.

Method 1: Upgrade ESXi 7 to ESXi 8 Using an ISO Image

The ISO-based upgrade method is one of the most commonly used approaches, especially for standalone hosts or environments without centralized lifecycle management.

This process involves booting the server using the ESXi 8 installation image and allowing the installer to upgrade the existing installation.

Step 1: Download the ESXi 8 ISO

Obtain the latest ESXi 8 ISO image from your VMware licensing portal or approved software repository.

Verify the file integrity before use.

Step 2: Access the ESXi Host

Open the ESXi Host Client and connect to your ESXi 7 server.

Review the host status and ensure no critical workloads are running.

Step 3: Place the Host in Maintenance Mode

Before upgrading, all virtual machines should be migrated or powered down.

To enter maintenance mode:

1. Open the ESXi Host Client.
2. Select the host.
3. Navigate to Manage.
4. Choose Maintenance Mode.
5. Enable maintenance mode.

The host must remain free of active virtual machines during the upgrade.

Step 4: Mount the ISO

Using your server’s remote management platform, such as:

• iLO
• iDRAC
• IPMI
• Remote Console

mount the ESXi 8 ISO image.

Configure the server to boot from the mounted ISO.

Step 5: Start the Upgrade Process

Reboot the server and launch the ESXi installer.

The installer will:

• Detect existing ESXi installations
• Present available storage devices
• Identify upgrade candidates

Select the disk containing the current ESXi installation.

Step 6: Confirm Upgrade Settings

The installer will display upgrade options and preserve existing configurations.

Review the settings carefully and proceed with the upgrade.

Step 7: Complete Installation

The upgrade process may take several minutes depending on hardware performance.

Once completed:

• Remove installation media
• Reboot the server
• Allow ESXi 8 to load

Step 8: Validate Host Functionality

After booting:

• Verify host connectivity
• Check networking
• Confirm storage visibility
• Review virtual switch configurations
• Validate VM functionality

The host should now be running ESXi 8 successfully.

Advantages of ISO Upgrades

• Simple process
• Suitable for standalone hosts
• No dependency on vCenter
• Useful for troubleshooting environments

Limitations

• Requires manual intervention
• Less efficient for large clusters
• Longer upgrade time for multiple hosts

Method 2: Upgrade ESXi Using the Command Line

For administrators comfortable with the command line, ESXi can be upgraded directly using VMware repositories.

This method eliminates the need for physical media and allows upgrades to be performed remotely.

Step 1: Enable SSH Access

Connect to the ESXi host and enable:

• SSH
• ESXi Shell

This allows administrative access to the host.

Step 2: Enter Maintenance Mode

As with any upgrade, ensure the host is in maintenance mode.

You can place the host into maintenance mode using:

• vCenter
• ESXi Host Client
• Command-line tools

Step 3: Enable HTTP Client Access

The ESXi firewall must allow repository access.

Run the following command:

esxcli network firewall ruleset set -e true -r httpClient

This permits communication with VMware software repositories.

Step 4: Update the ESXi Profile

Execute the upgrade command:

esxcli software profile update -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml -p ESXi-8.0.0-standard

The system will:

• Download required packages
• Verify dependencies
• Install updated components
• Update the boot image

Step 5: Review Results

Monitor the output carefully.

A successful upgrade will display confirmation messages indicating that the update completed successfully.

If errors occur, review:

• Network connectivity
• Repository access
• Storage availability
• Compatibility warnings

Step 6: Reboot the Host

Once the upgrade finishes, reboot the server.

reboot

The host will load the newly installed ESXi 8 environment.

Step 7: Verify Upgrade Completion

After startup:

• Confirm ESXi version
• Review system logs
• Validate storage connectivity
• Test virtual machine operations

Advantages of Command-Line Upgrades

• Fast deployment
• No physical media required
• Remote upgrade capability
• Efficient for experienced administrators

Limitations

• Requires command-line knowledge
• Less user-friendly
• Potential for syntax errors

Method 3: Upgrade Using vSphere Lifecycle Manager

For organizations managing multiple ESXi hosts through vCenter Server, vSphere Lifecycle Manager offers the most efficient upgrade method.

Lifecycle Manager automates host image management and compliance monitoring across clusters.

What Is vSphere Lifecycle Manager?

vSphere Lifecycle Manager provides centralized lifecycle management for:

• ESXi versions
• Drivers
• Firmware
• Vendor add-ons

Administrators can maintain consistency across clusters while simplifying upgrade operations.

Step 1: Log In to vCenter Server

Open the vSphere Client and connect to vCenter Server.

Select the cluster containing the hosts you want to upgrade.

Step 2: Open Updates Section

Navigate to:

Cluster → Updates

This section contains image management and compliance settings.

Step 3: Configure the Desired Image

Select:

Image → Setup Image

Choose:

• ESXi 8 version
• Vendor add-ons
• Additional components

Save the desired image configuration.

Step 4: Check Compliance

After creating the image, perform a compliance scan.

Lifecycle Manager compares current host versions against the desired image.

Hosts requiring updates will appear as:

Out of Compliance

Step 5: Review Upgrade Impact

Before remediation, review:

• Host availability
• Running workloads
• Maintenance mode requirements

This helps minimize operational impact.

Step 6: Start Remediation

Select:

Remediate All

Lifecycle Manager will:

• Place hosts into maintenance mode
• Apply updates
• Reboot hosts
• Validate compliance

The process occurs automatically according to cluster policies.

Step 7: Monitor Progress

Track remediation status through the vSphere Client.

Depending on cluster size, the upgrade process may take some time.

Step 8: Confirm Compliance

After remediation completes, all hosts should display:

Compliant

This confirms that every host matches the desired ESXi 8 image.

Advantages of Lifecycle Manager

• Centralized management
• Automated upgrades
• Cluster-wide consistency
• Reduced administrative effort
• Compliance monitoring

Limitations

• Requires vCenter Server
• Additional planning for large clusters

Which Upgrade Method Should You Choose?

The best upgrade method depends on your environment.

Use ISO Upgrade If:

• You manage standalone hosts.
• You prefer a graphical installation process.
• You need a straightforward upgrade path.

Use Command Line If:

• You are comfortable with ESXi CLI tools.
• Remote upgrades are required.
• Physical console access is unavailable.

Use Lifecycle Manager If:

• You manage multiple hosts.
• You use vCenter Server.
• You need automated cluster-wide upgrades.

For enterprise environments, Lifecycle Manager is generally the preferred solution due to its automation and consistency.

Post-Upgrade Best Practices

After upgrading to ESXi 8:

• Verify virtual machine performance.
• Check storage connectivity.
• Review networking configurations.
• Confirm backup operations.
• Update monitoring systems.
• Validate cluster functionality.
• Review VMware logs for warnings or errors.

A thorough post-upgrade validation helps ensure long-term stability.

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Conclusion

Upgrading from ESXi 7 to ESXi 8 is an important step toward improving virtualization performance, security, and manageability. VMware provides several upgrade paths to accommodate different environments and administrative preferences.

Whether you choose the ISO installer, command-line approach, or vSphere Lifecycle Manager, proper planning is essential for a successful migration. Always verify compatibility, back up critical data, and upgrade vCenter Server before upgrading your hosts.

By following a structured upgrade process and validating your environment afterward, you can take full advantage of ESXi 8’s capabilities while minimizing risk and downtime.

Also check: Manage multiple ESXi hosts & VM on the ESXi hosts

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