Glossary

Backup (vzdump) — a compressed archive of a whole guest, stored on backup storage, for restoring after disasters. Not the same as a snapshot.

Bridge (vmbr0) — a virtual network switch inside the host. Guests plug into it and appear as ordinary devices on your LAN.

Ceph — distributed storage across many nodes. Powerful, demanding, beyond this guide.

Clone — a copy of a VM or container. Linked clones share the source disk (fast, dependent); full clones are independent copies.

Cluster — several Proxmox nodes managed as one, allowing migration and high availability. Wants three nodes, shared storage, and good networking.

Container (LXC) — a guest that shares the host's kernel: lightweight, Linux-only, boots in about a second.

Content type — the kinds of files a storage accepts: iso, vztmpl, backup, images, rootdir.

Datacenter — the top of the resource tree: cluster-wide settings (storage definitions, backup jobs, users).

Guest — a VM or container running on the host. (You're the host's guest too, philosophically. Don't think about it.)

Guest agent — a small program inside the guest (qemu-guest-agent) that lets Proxmox shut it down cleanly, read its IP, and freeze it for snapshots.

Hypervisor — software that divides one physical computer into several virtual ones. Proxmox VE is a type 1 (bare-metal) hypervisor.

ISO — a disk image of an OS installer, uploaded to local storage and attached to a VM's virtual CD drive.

KVM — the Linux kernel's virtualization; what powers Proxmox VMs.

Linked clone — a clone sharing its template's disk, recording only differences. Fast and small; dies with the template.

LXC — Linux Containers: OS-level virtualization. See container.

LVM thin pool — the local-lvm storage: a flexible volume manager holding guest disks as block volumes.

Migration — moving a guest between cluster nodes, ideally while running.

noVNC — the in-browser console: a VM's screen in a web tab, no client software needed.

no-subscription repository — the free Proxmox update repository for users without a paid subscription key.

Node — one physical Proxmox machine. A cluster has several; a home lab usually has one.

QEMU — the machine emulator behind Proxmox VMs (with KVM doing the fast parts).

qm — the command-line tool for managing VMs.

pct — the command-line tool for managing containers.

Quorum — the majority agreement that lets a cluster make safe decisions. Why two-node clusters are fragile.

Snapshot — a frozen moment of a VM's disk: a rewind button for experiments, not disaster protection.

Storage — a place files can go, with declared content types. local (files) and local-lvm (guest disks) by default.

Template — a VM or container converted into a mold: can't be started, only cloned from.

VirtIO — fast paravirtualized drivers (network, disk) that guests use instead of emulated physical hardware.

VMID — the numeric ID of a guest (100 and up), chosen at creation.

vzdump — Proxmox's backup tool; also the name of the archives it produces.