# Provisioning

Some things a classroom needs cannot be installed by the classroom
package itself: they need the network, and they need the apt lock that
dpkg is holding for the whole of the package's `postinst`.

`ekklesia-classroom-provision.service` runs after every boot and does
them. It is a `oneshot` unit that nothing else waits on, so it never
holds the classroom up, and **it is not allowed to fail the boot**: a
machine with no DVD codecs is still a working classroom.

The package `postinst` enables the service and schedules a delayed start after
the outer apt transaction has had time to release its lock. It never runs
provisioning synchronously inside dpkg. If an OTA reboot happens before the
delayed job, the enabled service runs normally on the next boot.

To provision without waiting for a reboot:

```
sudo classroom-provision
```

Each step checks whether it is already done and returns immediately if
so. A provisioned machine costs nothing; a machine that was offline the
first time gets another go at the next boot.

```
journalctl -u ekklesia-classroom-provision
```

## Google Chrome

Chrome is not in Debian and a classroom is not usable without it, so a
fresh machine installs it itself rather than waiting for someone to do it
by hand on every box.

`classroom-chrome-setup` adds Google's signing key to
`/etc/apt/keyrings/google-chrome.gpg` and their repository to
`/etc/apt/sources.list.d/google-chrome.list` — the same path Google's own
package manages, so the two cannot become two copies of the same
repository — then installs `google-chrome-stable`. Using the repository
rather than a one-off `.deb` means Chrome keeps getting security updates.

Run it by hand with `sudo classroom-chrome-setup`. It returns
immediately if Chrome is already installed.

The Chrome policies in `/etc/opt/chrome/policies/` are shipped by the
classroom package and apply as soon as Chrome exists.

## DVD codecs

Only for rooms with `DVD_ENABLED=true`. See [dvd.md](dvd.md).

## Networking and printing

NetworkManager and CUPS are Debian package dependencies, not deferred network
provisioning steps. Their services are enabled by the package and neither
requires Internet access or hardware to be present.

- Wi-Fi administration: [networking.md](networking.md)
- Church color printer setup: [printing.md](printing.md)

The printer helper is part of every provisioning pass. It is capped at 30
seconds and only configures the local scheduler, so an offline Ricoh cannot
hold boot or provisioning open. Failures are logged and retried on the next
boot. A correctly configured queue is a quick no-op.

## What provisioning does not do

The boot provisioning command never upgrades or reconfigures anything already installed, and it
never touches a repository it did not add. Classroom software updates
are the OTA channel's job, not this.

## Permanent download addresses

```
https://updates.riverofglorymn.org/stable/latest.deb
https://updates.riverofglorymn.org/canary/latest.deb
```

One address per channel that never changes. Each is a symlink beside that
channel's manifest, pointing at the versioned package the manifest names,
so there is still exactly one record of which version is current — the
manifest. Nothing here is a second version database.

The versioned files under `/packages/` are never rewritten. A release
uploads its package, then the manifest, then swaps the pointer by rename.
Renaming is atomic, so nothing downloads a half-written pointer, and
going last means `latest.deb` can lag the manifest by a moment but can
never lead it: it will never offer a package the channel has not
published.

`latest.deb` and `manifest.json` are served `no-store, no-cache,
must-revalidate`. That header matters more than it looks: Cloudflare sits
in front of this server and caches `.deb` by extension, so without it a
room could be handed the previous release from an edge for hours. The
versioned packages are deliberately left cacheable — they are immutable.

**Installing from a channel URL does not move a machine onto that
channel.** `CHANNEL` in device.conf is the only thing that decides which
manifest the updater follows, and the package's postinst only ever
appends settings that are missing. Downloading the canary package to fix
a machine by hand leaves it on stable, and the next automatic update
brings it back to stable.

Verify a download against the channel it came from:

```
curl -fsSL -o c.deb https://updates.riverofglorymn.org/canary/latest.deb
sha256sum c.deb
curl -fsS https://updates.riverofglorymn.org/canary/manifest.json
```