Container

Containers share the host operating system kernel, making them far lighter than virtual machines. They start almost instantly and are ideal for running many services on a single home server. Docker and Podman are the most common container runtimes.

A container is created from an image — a read-only template that bundles the app and its dependencies — pulled from a registry like Docker Hub. Because the image contains everything the app needs, a container behaves the same on any host, eliminating 'works on my machine' problems. The trade-off versus a virtual machine is isolation: containers share the host kernel, so they're lighter but slightly less isolated than a full VM. For running many self-hosted apps efficiently on one box, that trade-off is almost always worth it; reserve VMs for workloads needing a different OS or stronger separation.