Prior to this commit, installation over serial console would requiring
manually having to modify the kernel modeline, as described in
https://github.com/NixOS/nixpkgs/issues/58198 .
This is unnecessarily fiddly, so this commit adds a syslinux boot
entry that has serial enabled.
GRUB already has a serial console entry:
2c07a0800a/nixos/modules/installer/cd-dvd/iso-image.nix (L311-L317)
Why 115200 bps? This is already used in other places, e.g. https://github.com/NixOS/nixpkgs/pull/58196
I tested this change by building the image, booting the image, and
observing the boot process over serial:
$ cd nixos/
$ nix-build -A config.system.build.isoImage -I nixos-config=modules/installer/cd-dvd/installation-cd-minimal.nix default.nix
$ sudo cp /nix/store/arcl702c3z8xlndlvnfplq9yhixjvs9k-nixos-20.09pre-git-x86_64-linux.iso/iso/nixos-20.09pre-git-x86_64-linux.iso /dev/sdb
$ picocom -b 115200 /dev/ttyUSB0
This reverts commit aab534b894 & uses the
driverInteractive attribute for the test driver instead.
This has the same effect but removes the extra module in the
nixos-build-vms code.
When I test a change e.g. in the module system manually, I usually use
`nixos-build-vms(8)` which also gives me a QEMU window where I can play
around in the freshly built VM.
It seems as this has changed recently when the default package for
non-interactive VM tests using the same framework was switched to
`pkgs.qemu_test` to reduce the closure size. While this is a reasonable
decision for our CI tests, I think that you really want a QEMU window of
the VM by default when using `nixos-build-vms(8)`.
[1] bc2188b083
The only nix version available in the installer should be the version
configure in the module system. If someone needs `nixUnstable` in their
`nixos-install` they should probably set the module option and not just
add it to the closure.
$EDITOR is allowed to contain flags, so it is important to allow the
shell to split this normally. For example, Sublime Text needs to be
passed --wait, since otherwise it will daemonise.
$NIXOS_CONFIG can be set to a directory, in which case the file used
is $NIXOS_CONFIG/default.nix. This updates 'nixos-rebuild edit' to
handle that case correctly.
This allows to perform `dd if= of=$img` after the image is built
which is handy to add e.g. uBoot SPL to the built image.
Instructions for some ARM boards sometimes contain this step
that needs to be performed manually, with this patch it can be
part of the nix file used to built the image.
