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losos

losos is a NixOS appliance for a mini-PC. It runs Nextcloud for your own files and can lend spare disk and CPU to a mesh of other losos boxes. There is no SSH and no login shell: you administer it from a web page, and it upgrades itself.

The root filesystem is a tmpfs that is rebuilt on every boot. Only directories listed in modules/impermanence.nix survive, on an encrypted /persist partition.

The owner's manual is the handbook (handbook/ in the repository), which every box also serves at http://<address>/handbook/ so it can be read from the LAN alone. The pages below are for people who build and run the project.

Pages

• Install — installer ISO, Secure Boot, TPM, demo image, growing the disk
• Administration — the admin UI, settings, upgrades and the nightly reboot
• Mesh — contributing storage and compute to other boxes
• Master proxy — reaching the box from the internet without opening a port
• Hardening — the default hardening baseline and the opt-in flags
• Security model — what is and is not defended
• Architecture — how the pieces fit together
• Development — dev shell, tests, lock files
• CI and releases — CI jobs, release media, the binary cache

Compared with alternatives

• A NAS (Synology, QNAP). Same idea of a box with a web UI. The difference is that the root here is discarded on every boot, so an attacker's changes last until the next reboot (at 00:07 each night at the latest). You can also read and rebuild everything the box runs.
• A VPS. The box is in your home and its disk is encrypted; the key is sealed to the box's TPM chip (or, on a machine without one, kept on the boot partition). The optional master proxy gives it a public address without an inbound port.
• Plain NixOS. You could write all of this yourself. Here it is already written, and the user isolation, encrypted persistence, disk growth, hardening and mesh gating are each tested in a VM.
• Other self-hosting stacks. None of them lend capacity to a mesh only when the owner's time window is open and the box is idle.

What it is not

• Not a general-purpose server. There is no shell by design.
• Not a backup. Keep copies of /persist somewhere else.
• Not finished.