systemd-nspawn

Lightweight namespace container

TLDR

Run a command in a container

$ systemd-nspawn -D [path/to/container_root]

Run a full Linux OS in a container (boot)

$ systemd-nspawn -b -D [path/to/container_root]

Run the command as PID 2 using a stub init process

$ systemd-nspawn -D [path/to/container_root] -a

Specify the machine name and hostname

$ systemd-nspawn -M [container_name] --hostname [hostname] -D [path/to/container_root]

SYNOPSIS

systemd-nspawn [options] [command] [arguments]

systemd-nspawn spawns a command or full operating system in a lightweight container. It uses Linux namespaces and cgroups for isolation but is simpler than full container solutions like Docker.
The tool is useful for testing, building packages, and running isolated services. With --boot, it can run a complete init system, making it suitable for system containers.

PARAMETERS

-D, --directory _path_

Root directory of the container

-b, --boot

Boot the container's init system

-M, --machine _name_

Set the machine name

-a, --as-pid2

Run command as PID 2 with stub init

--hostname _name_

Set the container hostname

-u, --user _user_

Run as specified user

--bind _src:dest_

Bind mount host path into container

-n, --network-veth

Create a virtual Ethernet link

--private-network

Disconnect from host network

CAVEATS

Requires root privileges. The container filesystem must contain a complete OS or at least the required binaries. Network isolation requires additional configuration. Part of the systemd suite.