The virtualization technology behind a VPS plan determines far more than a line in the spec sheet. It decides whether you can run Docker, load custom kernel modules, install a different operating system, and how much of the physical CPU you actually get under load. KVM, OpenVZ, and LXC are the three families you will meet when shopping for a Linux VPS, and they behave very differently once you start pushing them. This guide explains how each one works, what it allows you to run, and how to find out which one your provider is using.
What “virtualization type” actually means
A VPS is a slice of a physical server. The software that carves out that slice is either a hypervisor (full virtualization) or a container runtime (OS-level virtualization). That distinction controls the boundary between your instance and the host kernel: a hypervisor gives you a separate kernel of your own, while a container runtime makes you share the host kernel with every other tenant. Each approach has real performance and compatibility trade-offs, so the choice is not purely academic.
KVM: full virtualization with hardware support
KVM (Kernel-based Virtual Machine) turns the Linux kernel into a type-1 hypervisor using hardware virtualization extensions such as Intel VT-x and AMD-V. Every KVM instance gets its own kernel, its own boot process, and complete isolation from the host and from other tenants. You can run any operating system the provider offers images for, load kernel modules, tweak kernel parameters, and run Docker natively.
The price of that flexibility is a small performance overhead: the hypervisor sits between the guest and the hardware, which costs a few percent of CPU throughput in most workloads. Each guest kernel also uses a bit of RAM for itself, so KVM nodes typically hold fewer tenants per host than container-based setups. For most web workloads the overhead is invisible, and the isolation is worth it.
- Run Docker, Kubernetes, and other container runtimes natively
- Load custom kernel modules and change kernel parameters
- Full isolation from noisy neighbors on the same host
- Any OS: Debian, Ubuntu, AlmaLinux, and more
OpenVZ: shared-kernel containers
OpenVZ is OS-level virtualization: all “VPSes” on a host share a single kernel. Overhead is tiny and density is high, which is why OpenVZ was popular for budget plans. The catch is that you inherit the host kernel’s version, its feature set, and its restrictions. You cannot run Docker easily, you cannot load kernel modules, and most kernel parameters are off-limits.
Modern OpenVZ 7 (Virtuozzo) improved parts of this, but many cheap OpenVZ offers in the wild are legacy versions with old kernels. From a performance standpoint, a shared kernel means host-wide events affect everyone: a runaway process on another tenant or a host-level issue can degrade your instance too. If a provider only offers OpenVZ for the plan you want, treat it as a compatibility warning for anything beyond basic web hosting.
LXC / LXD: container-based with modern tooling
LXC is also shared-kernel, but it uses modern cgroup v2 and namespace isolation, and the LXD management layer makes system containers feel close to real VMs. You get an init system, you can install packages, run sshd, and manage the container like a small server. Performance is near-native because there is no hypervisor in the path.
The limits mirror OpenVZ in principle: you are restricted to the kernel the host provides, kernel modules are constrained, and OS choices are limited to Linux flavors. For simple web hosting, LXC is a legitimate budget option. For anything involving Docker, custom kernels, or unusual software, KVM remains the safer bet.
KVM vs OpenVZ vs LXC: side-by-side
| Feature | KVM | OpenVZ | LXC / LXD |
|---|---|---|---|
| Isolation | Full (separate kernel) | Shared kernel | Shared kernel (namespaces) |
| Kernel access | Own kernel, modules OK | Host kernel only | Host kernel, limited modules |
| OS choice | Any provider image | Linux only | Linux only |
| Docker support | Native | Not practical | Limited / nested |
| Performance overhead | Small (hypervisor layer) | Near-zero | Near-zero |
| Typical use | Production, Docker, DBs | Legacy budget plans | Budget web hosting |
How to check which virtualization your VPS uses
You do not need to ask support. A few commands reveal the technology in seconds:
systemd-detect-virt— printskvm,lxc,openvz, or similargrep -c hypervisor /proc/cpuinfo— a non-zero count usually means KVMdmesg | grep -i -E "kvm|hypervisor"— boot messages often name the hypervisorlsblk—vd*block devices indicate virtio/KVM storagecat /proc/user_beancounters— if this file exists, you are on OpenVZ
Which virtualization should you choose?
Match the technology to the workload rather than the price tag:
- Choose KVM if you run Docker, databases, custom kernels, or anything you may need to migrate later.
- LXC/LXD is fine for simple, low-traffic web hosting where near-native performance and low cost matter.
- Avoid legacy OpenVZ for new production work; it limits Docker, modules, and modern kernels.
Before you commit to a provider, see the full VPS comparison on our table to compare virtualization types, specs, and pricing side by side, and browse our provider breakdowns and buying guides on the main site for deeper guidance on matching plans to workloads.
Looking for a place to run these setups? InterServer VPS plans offer straightforward pricing with plenty of headroom, and Cloudways managed cloud hosting is a solid choice if you prefer a managed platform on top of fast infrastructure. (Disclosure: we may earn a commission if you sign up through these links, at no extra cost to you.)
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