I'm building my virtualization skills and am trying to decide whether ESXi is still worth prioritizing after the recent licensing and ownership changes, or whether I should focus on Proxmox, KVM, and Hyper-V instead. I don't have a spare server that I can wipe, but my company has an unused shared server available. My plan is to install VMware Workstation Pro on the existing operating system and run ESXi inside it as a nested lab. What performance, storage, CPU, and networking limitations should I expect? How can I isolate the lab so that its virtual machines cannot leak DHCP or disrupt the host network? Finally, which virtualization concepts should I learn first, and are there any worthwhile video or documentation resources?
6 Answers
Use the official documentation for whichever platform you choose, then build small labs instead of only watching videos. Start with creating and sizing virtual machines, installing guest tools, configuring virtual networking, managing storage, taking backups, and recovering from failures. After that, practice permissions, automation, monitoring, live migration, clustering, and a small multi-node design. Learning how the components work underneath the management interface will help much more than memorizing one product’s menus.
ESXi is still relevant because many established organizations continue to run it, so it can be valuable if a particular employer or target role uses it. However, the market is changing quickly because of licensing costs and vendor changes. Proxmox and KVM are easier to obtain for a home lab, while Hyper-V is also worth knowing in Windows-heavy environments. A broad foundation plus basic experience with several platforms is probably a better investment than specializing in only ESXi.
The safest long-term approach is to learn virtualization fundamentals rather than tying yourself to one vendor. Focus on CPU and memory allocation, virtual disks and storage tiers, snapshots, templates, migrations, clustering, quorum, backups, and troubleshooting. Networking is especially transferable: understand vNICs, bridges and virtual switches, VLANs, uplinks, and how management, storage, migration, and guest traffic are separated. Once those concepts make sense, moving between ESXi, Proxmox, Hyper-V, and other KVM-based platforms is much easier.
It is also useful to understand how each platform handles clustering and shared storage. Those topics come up frequently when organizations migrate away from one hypervisor or consolidate several environments.
Nested ESXi can work well for learning, but it is not a performance benchmark. Enable hardware virtualization and nested virtualization in the host and firmware, give the lab fast local storage, and leave enough CPU and RAM for the host operating system. Expect extra overhead, limited or emulated device support, and more complicated troubleshooting. For networking, use an isolated internal or host-only virtual switch with no connection to the physical adapter. Put the lab behind a dedicated virtual router or firewall, disable any guest DHCP service unless you control it, and avoid bridging the lab directly onto the company LAN. Test with harmless guests first and get permission before using shared company hardware.
A separate VLAN or physically separate interface is even better when available, but a host-only network is the simplest way to prevent accidental DHCP broadcasts from reaching the production network.
For a home lab, Proxmox or a plain KVM setup is usually more practical because it is inexpensive and accessible. You can still learn the same core ideas and later build an ESXi lab if a job requires it. Hyper-V is another useful option, particularly if the lab machine already runs a supported Windows edition.
The best choice depends on your career target. If a prospective employer still operates VMware, learning ESXi and the surrounding management stack is worthwhile. Otherwise, begin with Proxmox or KVM, add Hyper-V, and learn enough ESXi to understand its terminology and administration. Companies are increasingly looking for people who can evaluate platforms and migrate workloads, not just operate one hypervisor.
Even smaller organizations and educational environments may still have a few ESXi hosts, so it is not useless. I just would not make it the only virtualization platform you learn.