The reasons for migrating to the cloud vary: rising operating costs, new security requirements or greater flexibility. Especially with complex system landscapes, a predictable, controlled move is crucial.
Anyone running systems that have grown over many years knows the challenges. The infrastructure works but is no longer up to date. Updates are risky, hardware can no longer be sourced, know-how leaves the company. Migrating to a new, clean environment – for example a VMware-based cloud infrastructure – makes technical sense but is often not directly possible. Especially when changing hypervisor, for instance from Hyper-V, KVM or Proxmox to a VMware environment, classic migration reaches its limits. Cold migration also offers a clearly structured and reliable route for moving physical systems onto a virtual platform.
What sets cold migration apart from other approaches
In a cold migration, virtual machines are transferred to a new cloud environment while powered off. No data is transferred during operation, which prevents potential inconsistencies. This approach is particularly suited to systems where no ongoing changes can be tolerated or a clean cut is required. It also makes it possible to change the virtualisation platform.
Platform-independent migration with a clear structure
A major advantage of cold migration is its technical independence from the source environment. By using VMware Cloud Director Availability (VCDA), the entire virtual machine is replicated directly, without requiring a specific export format or additional third-party tools. This means that regardless of whether the VM previously ran on Hyper-V, Proxmox, KVM or another hypervisor, the cloning process works automatically and completely via the Netstream infrastructure.
No intermediate step with VMDK, OVF or OVA is necessary. Tools such as Veeam, Acronis or Clonezilla are not required for this process either. The migration is carried out in a structured way via the VMware Cloud Director Availability stack. This significantly reduces the complexity of preparation, which is crucial for heterogeneous or historically grown environments in particular.
After the import, the machine is first provisioned in a separate resource pool in the target system. There, all components such as network adapters, firewall rules, disks or resource classes can be adjusted and tested before the machine goes into operation.
Netstream supports cold migration from the following environments, among others:
- VMware vSphere or ESXi
- Microsoft Hyper-V
- Nutanix AHV
- Proxmox VE
- KVM-based systems
- Bare metal systems
Preparing network, storage and security
The network connection can also be fully configured in advance. VMware NSX can be used to map VLANs, gateways, NAT rules and VPN endpoints. For hybrid scenarios, an IPsec connection between the source and target systems is available.
Various storage classes can be used. The range extends from standard to IOPS-optimised SSD volumes. Allocation is per virtual disk, so performance and costs can be managed precisely.
An additional snapshot can be created before the switchover. This keeps the original virtual machine available as a fallback option for a defined period. The production start is planned, often outside normal business hours.
Conclusion: platform-independent migration with a clear structure
Cold migration is particularly suitable when systems are to be transferred from an existing infrastructure into a new VMware environment independently. Typical scenarios are moving from Hyper-V, Proxmox or KVM to VMware or virtualising formerly physical servers. Since each virtual machine is started and migrated individually via a prepared image, the transfer takes place sequentially and specifically for each system.
This method makes it possible to move individual machines into a new environment in a controlled way, without regard to compatibilities or dependencies within the source system. The source and target environments do not need to use the same virtualisation technology. Network configurations, hostnames and operating systems can be reviewed and adjusted as part of the migration.
The target environment is based on VMware Cloud Director. It has a multi-tenant design and offers features such as resource reservation, API control, role-based access management, backup integration and reporting as standard.
