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Migrating VMs from VMware ESXi to Proxmox

In response to Broadcom’s recent alterations in VMware’s subscription model, an increasing number of enterprises are reevaluating their virtualization strategies. With heightened concerns over licensing costs and accessibility to features, businesses are turning towards open source solutions for greater flexibility and cost-effectiveness. Proxmox, in particular, has garnered significant attention as a viable alternative. Renowned for its robust feature set and open architecture, Proxmox offers a compelling platform for organizations seeking to mitigate the impact of proprietary licensing models while retaining comprehensive virtualization capabilities. This trend underscores a broader industry shift towards embracing open-source technologies as viable alternatives in the virtualization landscape. Just to mention, Proxmox is widely known as a viable alternative to VMware ESXi but there are also other options available, such as bhyve which we also covered in one of our blog posts.

Benefits of Opensource Solutions

In the dynamic landscape of modern business, the choice to adopt open source solutions for virtualization presents a strategic advantage for enterprises. With platforms like KVM, Xen and even LXC containers, organizations can capitalize on the absence of license fees, unlocking significant cost savings and redirecting resources towards innovation and growth. This financial flexibility empowers companies to make strategic investments in their IT infrastructure without the burden of proprietary licensing costs. Moreover, open source virtualization promotes collaboration and transparency, allowing businesses to tailor their environments to suit their unique needs and seamlessly integrate with existing systems. Through community-driven development and robust support networks, enterprises gain access to a wealth of expertise and resources, ensuring the reliability, security, and scalability of their virtualized infrastructure. Embracing open source virtualization not only delivers tangible financial benefits but also equips organizations with the agility and adaptability needed to thrive in an ever-evolving digital landscape.

Migrating a VM

Prerequisites

To ensure a smooth migration process from VMware ESXi to Proxmox, several key steps must be taken. First, SSH access must be enabled on both the VMware ESXi host and the Proxmox host, allowing for remote management and administration. Additionally, it’s crucial to have access to both systems, facilitating the migration process. Furthermore, establishing SSH connectivity between VMware ESXi and Proxmox is essential for seamless communication between the two platforms. This ensures efficient data transfer and management during migration. Moreover, it’s imperative to configure the Proxmox system or cluster in a manner similar to the ESXi setup, especially concerning networking configurations. This includes ensuring compatibility with VLANs or VXLANs for more complex setups. Additionally, both systems should either run on local storage or have access to shared storage, such as NFS, to facilitate the transfer of virtual machine data. Lastly, before initiating the migration, it’s essential to verify that the Proxmox system has sufficient available space to accommodate the imported virtual machine, ensuring a successful transition without storage constraints.

Activate SSH on ESXi

The SSH server must be activated in order to copy the content from the ESXi system to the new location on the Proxmox server. The virtual machine will later be copied from the Proxmox server. Therefore, it is necessary that the Proxmox system can establish an SSH connection on tcp/22 to the ESXi system:

Find Source Information about VM on ESXi

One of the challenging matters in finding the location of the virtual machine holding the virtual machine disk. The path can be found within the web UI of the ESXi system:

Create a New Empty VM on Proxmox

Copy VM from ESXi to Proxmox

The content of the virtual machine (VM) will be transferred from the ESXi to the Proxmox system using the open source tool rsync for efficient synchronization and copying. Therefore, the following commands need to be executed from the Proxmox system, where we create a temporary directory to store the VM’s content:

mkdir /tmp/migration_pgsql07.gyptazy.ch
cd /tmp/migration_pgsql07.gyptazy.ch
rsync -avP root@esx02-test.gyptazy.ch:/vmfs/volumes/137b4261-68e88bae-0000-000000000000/pgsq07.gyptazy.ch/* .

Depending on the file size of them virtual machine and the network connectivity this process may take some time.

Import VM in Proxmox

Afterwards, the disk is imported using the qm utility, defining the VM ID (which got created during the VM creation process), along with specifying the disk name (which has been copied over) and the destination data storage on the Proxmox system where the VM disk should be stored:

qm disk import 119 pgsql07.gyptazy.ch.vmdk local-lvm

Depending on the creation format of the VM or the exporting format there may be multiple disk files which may also be suffixed by _flat. This procedure needs to be repeated by all available disks.

Starting the VM

In the final step, all settings, resources, definitions and customizations of the system should be thoroughly reviewed. One validated, the VM can be launched, ensuring that all components are correctly configured for operation within the Proxmox environment.

Conclusion

This article only covers one of many possible methods for migrations in simple, standalone setups. In more complex environments involving multiple host nodes and different storage systems like fibre channel or network storage, there are significant differences and additional considerations. Additionally, there may be specific requirements regarding availability and Service Level Agreements (SLAs) to be concern. This may be very specific for each environment. Feel free to contact us for personalized guidance on your specific migration needs at any time. We are also pleased to offer our support in related areas in open source such as virtualization (e.g., OpenStack, VirtualBox) and topics pertaining to cloud migrations.

Addendum

On the 27th of March, Proxmox released their new import wizard (pve-esxi-import-tools) which makes migrations from VMware ESXi instances to a Proxmox environment much easier. Within an upcoming blog post we will provide more information about the new tooling and cases where this might be more useful but also covering the corner cases where the new import wizard cannot be used.