# sdme
Lightweight systemd-nspawn containers with overlayfs.
## Quick install
Download a static binary from [fiorix.github.io/sdme](https://fiorix.github.io/sdme/).
Runs on Linux with systemd. Uses kernel overlayfs for copy-on-write storage. By default, containers are overlayfs clones of `/` but you can also import rootfs from other distros (Ubuntu, Debian, Fedora, NixOS; see [docs/nix](docs/nix/)).
**Why does this even exist?**
Here's my pitch: from a linux system with just systemd and sdme, you can create and run any container and cloud image that exists today.
Check out the [sdme architecture](docs/architecture.md) for details about what this is and how it works. The containers we create are booted systemd containers.
**On macOS?** See [docs/macos.md](docs/macos.md) for instructions using lima-vm.
## Usage
Cloning your own "/" filesystem:
```bash
sudo sdme new
```
By default, host-rootfs containers (no `-r`) make `/etc/systemd/system` and `/var/log` opaque so the host's systemd overrides and log history don't leak in. Override with `-o` or change the default via `sdme config set host_rootfs_opaque_dirs`.
Importing a root filesystem on Ubuntu with debootstrap:
```
$ debootstrap --include=dbus,systemd noble /tmp/ubuntu
$ sudo sdme fs import ubuntu /tmp/ubuntu
$ sudo sdme new -r ubuntu
```
## Importing filesystem from an OCI container
Fedora:
```
sudo sdme fs import fedora quay.io/fedora/fedora
sudo sdme new -r fedora
```
Debian:
```
sudo sdme fs import debian docker.io/debian
sudo sdme new -r debian
```
sdme can also run OCI application images (nginx, mysql, etc.) as systemd services inside a base container, with optional cross-container access via connectors. See [docs/oci.md](docs/oci.md) for details.
## Dependencies
### Runtime
| `systemd` (>= 252) | `systemd` | All commands (D-Bus communication) |
| `systemd-nspawn` | `systemd-container` | Running containers (`sdme start`) |
| `machinectl` | `systemd-container` | `sdme join`, `sdme exec`, `sdme new` |
| `journalctl` | `systemd` | `sdme logs` |
| `qemu-nbd` | `qemu-utils` | `sdme fs import` (QCOW2 images only) |
### Install all dependencies (Debian/Ubuntu)
```bash
sudo apt install systemd-container
```
For QCOW2 image imports, also install `qemu-utils`.
## Build
```bash
cargo build --release # build the binary
cargo test # run all tests
cargo test <test_name> # run a single test
make # same as cargo build --release
sudo make install # install to /usr/local (does NOT rebuild)
```