Recommendations for Migrating from VMware ESXi to Proxmox VE: A Technical Guide for a Safe Transition

Migrating from VMware ESXi to Proxmox VE is a decision that more and more organizations are considering, whether due to the evolution of licensing models, the need to reduce costs, or the pursuit of a more flexible and controlled open-source environment. While it may seem like a complex process, with proper planning and following best practices, the transition can be executed in a controlled manner without critical impact. Additionally, such projects allow for a review of existing infrastructure and modernization of aspects that are usually overlooked due to the daily routine of operations.

Below, we share a technical guide with key recommendations to successfully undertake this migration, minimizing risks and leveraging the advantages of Proxmox VE from the outset.

Planning: The Pillar of a Successful Migration

Before moving a single virtual machine, it is essential to prepare the groundwork. Good planning drastically reduces downtime and avoids mistakes that could compromise the availability of essential services.

1. Infrastructure Assessment
   Document all VMs, network configurations, storage dependencies, and specific features such as snapshots, independent disks, driver configurations, or templates.

2. Hardware Compatibility
   Check that your physical hardware (servers, NICs, RAID controllers, processors, etc.) is compatible with Proxmox VE. You can consult the official hardware compatibility list or rely on community experiences. Also, verify compatibility with technologies such as Intel VT-x or AMD-V and support for nested virtualization if needed.

3. Complete and Tested Backup
   Create consistent backups of all virtual machines. Verify their integrity through restorations in a test environment and document the procedure to act quickly in case of any incidents.

4. Pre-Migration Testing in a Non-Production Environment
   Before migrating the actual environment, create a lab with Proxmox VE. Here, you can import VMs, check compatibilities, conduct performance tests, and validate specific configurations such as connectivity with shared storage or replication.

Proxmox VE Testing: Preparing the New Environment

1. Clean Installation of Proxmox VE
   Download the latest version and install it following the official recommendations. Apply good security practices from the start, such as separating the management network, disabling unnecessary services, and restricting IP-based accesses.

2. Conversion of Virtual Disks
   Convert VMDK disks to QCOW2 or RAW using tools such as qemu-img. Since Proxmox 8, there’s an integrated tool to simplify this step. Also, consider the differences between disk and network drivers (e.g., virtio vs. e1000).

3. Creation and Importation of VMs
   Recreate the original configuration of the VMs and import the converted disks. Use the web interface or CLI. Proxmox allows customization of virtual hardware and the definition of CPU, memory, and I/O priority limits.

4. Network Configuration
   Define bridges, VLANs, firewalls, and zones to reflect the previous architecture and enhance security. If you were using distributed networks or DVS in VMware, consider how to replicate that logic in Proxmox with bridges and Linux-based network configurations.

5. Functional Validation
   Test all functions of the migrated VMs: connectivity, performance, access to services, data integrity. Check logs from the operating system, user access, service status, and connections to databases or other shared resources.

Production Migration: How to Execute the Change

Once testing is complete, you can initiate the migration in the production environment:

• Plan an appropriate maintenance window.
• Migrate less critical VMs first to validate the process live.
• Prioritize high-impact VMs and conduct tests after each migration.
• Consider running both environments in parallel during a transition phase.
• Conduct cross-checks with end users to ensure everything is functioning as expected.

Post-Migration: Consolidation and Optimization

1. Proactive Monitoring
   Integrate tools like Prometheus, Zabbix, or Proxmox’s own metrics server. Create dashboards to identify bottlenecks and early failures.

2. Adjustments and Improvements
   Optimize assigned resources, enable HA, configure automatic backups with vzdump or external solutions. Ensure you have planned snapshots and adequate retention policies.

3. Detailed Documentation
   Record the entire process: errors, solutions applied, structural changes. Include network maps, storage configurations, and internal VM migration and restoration procedures.

4. Team Training
   Train the team in managing Proxmox VE: CLI, GUI, snapshots, backup, and upgrades. Familiarize administrators with tools like pct, qm, pvesh, and the Proxmox API for future automation.

Additional Considerations

• Security Updates
  Apply patches regularly on both the host and VMs. Consider using enterprise repositories if you acquire a subscription.

• Access Security
  Enable 2FA, define RBAC roles, enhance network segmentation, configure audits, and limit access through certificates or jump servers.

• Official Proxmox Support
  In critical environments, having a support subscription can make a significant difference. It provides access to validated updates, direct assistance, and support for incidents.

Conclusion

Migrating from VMware ESXi to Proxmox VE is not just a technological change: it’s an opportunity to improve performance, reduce costs, modernize processes, and adopt a more open and sustainable platform. At Stackscale (Grupo Aire), we assist companies in making this leap with assurance, supporting the entire process from initial evaluation to post-migration optimization, integrating the new environment into a modern, secure, and scalable cloud architecture.

Contact us to plan your transition to a Proxmox VE-based infrastructure.