Package Center and containers

6 min · 10 sections

The NAS runs applications — a movie server with artwork, a private cloud, the whole house's ad blocker — each locked in its own container, without touching the system. The Package Center installs and updates them in one click; the Containers app shows the machinery underneath, for when you need to look.

You need a volume already created: applications and their data live on the volume (<pool>/apps/<application>/), never on the system disk — an app that grows fat cannot leave the NAS without room to update itself.

Installing

Pick the app in the catalogue —by category or searching— and press "Install". The download and startup run as a task with progress; when it finishes, apps with a web interface carry the "Open" button, which lands you on their screen. Each application keeps its own things in its data folder on the volume: reinstalling or updating never touches what is stored.

"Update" pulls the new image version and recreates the container with the same settings. The data is not even looked at: it lives in its folder, outside the container.

The catalogue

The catalogue has 1058 applications, all from other developers, curated by us and tested one by one: each recipe is really installed, its web page opened and removed before it goes in. They have their category, their icon and a fixed version: an application never changes version on its own, and «Update» brings it up to date when you ask. The recipes point their data to the NAS data folder, so the «everything in the volume» rule holds for all of them.

Ports and folders

Every installed app has its "Ports and folders" button:

• Ports: which NAS port leads to which port inside the container. If the one the recipe proposes clashes with something of yours, change it here and the app is recreated with the new one.
• Folders: which NAS folders the app sees from inside. It is how you hand a movie server your Movies folder, or let a backup app see what it has to copy.

For whatever the screen does not cover there is advanced editing: the full recipe (docker compose) and its variables, editable as is. With a safety net: on apply, the containers are recreated with the new recipe and, if they do not come up, the previous configuration is restored automatically — a syntax slip does not leave the app dead.

Video acceleration

If the NAS has integrated graphics (Intel or AMD), Jellyfin and Plex can use it to convert video without loading the processor: the difference between watching a film and watching a spinner. When installing them a «Video acceleration» switch appears, and for an already installed app it lives in «Ports and folders». It is the only thing of the machine an app can receive: the graphics; no disks, no other devices.

An Nvidia card

If the NAS has an Nvidia card, the same switch works for it as soon as three things are true: the driver is loaded (/dev/nvidia0 exists, which shows up after installing it and rebooting, or after running nvidia-smi once), the Nvidia container runtime is installed, and that runtime is registered with Docker. It is a one-off, from the NAS console:

sudo apt install nvidia-driver nvidia-container-toolkit
sudo nvidia-ctk runtime configure --runtime=docker
sudo systemctl restart docker

The nvidia-driver package lives in Debian's non-free section and nvidia-container-toolkit in Nvidia's repository. Until they are there the option does not show up: the panel only offers it when it knows it will work.

USB devices

Home Assistant with a Zigbee or Z-Wave USB stick needs to see the adapter. When installing it, and in «Ports and folders», the serial-port adapters plugged into the NAS are listed by name; tick the one you want and the app finds it at /dev/serial/by-id/…, a name that does not change when you plug it back in. Serial ports only: a USB disk or any other device stays out of the apps' reach.

Memory and CPU limits

In «Ports and folders» of each installed app you can set how much memory and CPU it may use at most. Without a limit, a runaway app (a photo indexer, a badly tuned database) eats the NAS memory and drags the panel and the other apps down. The steps offered are the ones that fit your machine; «No limit» removes them. The change restarts the app.

Uninstalling

"Uninstall" stops the app and takes it off the list, and says it plainly: the data is kept on disk. Reinstalling it tomorrow brings it back with everything it had. If what you want is the space back, the option to also delete the data does it for real — and if something could not be deleted, it says so with a name and a reason instead of pretending it came out clean.

Containers, logs and console

The Containers app shows what actually runs: each container with its state, memory and processor.

• Logs: the container's output, searchable — the first place to look when an app will not start or acts strangely.
• Console: a terminal inside the container, for the look no panel can give.
• Stop, start and restart individual containers. Careful with removing a Package Center application's container: it does not uninstall it —it will be created again on update—, it only leaves it stopped. To really remove it, "Uninstall" in the Package Center.

Cleanup

Docker leaves old images behind with every update, and they take gigabytes nobody uses. The cleanup button gets them back: it deletes what no container references any more —orphaned images, loose layers— and says how much it freed. Apps and their data are not touched.

How it fits with the rest

• App data folders are normal volume folders: they go into backups and snapshots like everything else.
• If the volume is destroyed or moved, the panel relocates Docker and tells you which apps need reinstalling: it is covered in Disks, spares and replicas.
• To publish your own recipes into the catalogue there is the administration guide.