---
title: "router7: installation"
menu:
  main:
    title: "Installation"
    weight: 30
---

# Installation

Connect your serial adapter ([usbcom1a](https://pcengines.ch/usbcom1a.htm) works well if you don’t have one already) to the apu2c4 and start a program to use it, e.g. `screen /dev/ttyUSB0 115200`. Then, power on the apu2c4 and configure it to do PXE boot:

* Press `F10` to enter the boot menu
* Press `3` to enter setup
* Press `n` to enable network boot
* Press `c` to move mSATA to the top of the boot order
* Press `e` to move iPXE to the top of the boot order
* Press `s` to save configuration and exit

Connect a network cable on `net0`, the port closest to the serial console port:

<img src="https://github.com/rtr7/router7/raw/master/devsetup.jpg"
width="800" alt="router7 development setup">

Next, build a router7 image:

```shell
go get -u github.com/gokrazy/tools/cmd/gokr-packer github.com/rtr7/tools/cmd/...
go get -u -d github.com/rtr7/router7
mkdir /tmp/recovery
GOARCH=amd64 gokr-packer \
	-hostname=router7 \
	-overwrite_boot=/tmp/recovery/boot.img \
	-overwrite_mbr=/tmp/recovery/mbr.img \
	-overwrite_root=/tmp/recovery/root.img \
	-eeprom_package= \
	-kernel_package=github.com/rtr7/kernel \
	-firmware_package=github.com/rtr7/kernel \
	-gokrazy_pkgs=github.com/gokrazy/gokrazy/cmd/ntp \
	-serial_console=ttyS0,115200n8 \
	github.com/rtr7/router7/cmd/...
```

Run `rtr7-recover -boot=/tmp/recovery/boot.img -mbr=/tmp/recovery/mbr.img -root=/tmp/recovery/root.img` to:

* trigger a reset [if a Teensy with the rebootor firmware is attached](#rebootor)
* serve a DHCP lease to all clients which request PXE boot (i.e., your apu2c4)
* serve via TFTP:
  * the PXELINUX bootloader
  * the router7 kernel
  * an initrd archive containing the rtr7-recovery-init program and mke2fs
* serve via HTTP the boot and root images
* optionally serve via HTTP a backup.tar.gz image containing files for `/perm` (e.g. for moving to new hardware, rolling back corrupted state, or recovering from a disk failure)
* exit once the router successfully wrote the images to disk

## Updates

Run e.g. `rtr7-safe-update -updates_dir=$HOME/router7/updates` to:

* verify the router currently has connectivity, abort the update otherwise
* download a backup archive of `/perm`
* build a new image
* update the router
* wait until the router restored connectivity, roll back the update using `rtr7-recover` otherwise

The update step uses kexec to reduce the downtime to approximately 15 seconds.

## Manual Recovery

Given `rtr7-safe-update`’s safeguards, manual recovery should rarely be required.

To manually roll back to an older image, invoke `rtr7-safe-update` via the
`recover.bash` script in the image directory underneath `-updates_dir`, e.g.:

```shell
% cd ~/router7/updates/2018-07-03T17:33:52+02:00
% ./recover.bash
```

## Teensy rebootor {#rebootor}

The cheap and widely-available [Teensy++ USB development board](https://www.pjrc.com/store/teensypp.html) comes with a firmware called rebootor, which is used by the [`teensy_loader_cli`](https://www.pjrc.com/teensy/loader_cli.html) program to perform hard resets.

This setup can be used to programmatically reset the apu2c4 (from `rtr7-recover`) by connecting the Teensy++ to the [apu2c4’s reset pins](http://pcengines.ch/pdf/apu2.pdf):
* connect the Teensy++’s `GND` pin to the apu2c4 J2’s pin 4 (`GND`)
* connect the Teensy++’s `B7` pin to the apu2c4 J2’s pin 5 (`3.3V`, resets when pulled to `GND`)

You can find a working rebootor firmware .hex file at https://github.com/PaulStoffregen/teensy_loader_cli/issues/38

## Prometheus

See https://github.com/rtr7/router7/tree/master/contrib/prometheus for example
configuration files, and install the [router7 Grafana
Dashboard](https://grafana.com/dashboards/8288).