This change removes the bespoke logic around identifying block devices.
Instead of trying to find the right device by iterating over
`qemu.drives` and guessing the right partition number (e.g.
/dev/vda{1,2}), devices are now identified by persistent names provided
by udev in /dev/disk/by-*.
Before this change, the root device was formatted on demand in the
initrd. However, this makes it impossible to use filesystem identifiers
to identify devices. Now, the formatting step is performed before the VM
is started. Because some tests, however, rely on this behaviour, a
utility function to replace this behaviour in added in
/nixos/tests/common/auto-format-root-device.nix.
Devices that contain neither a partition table nor a filesystem are
identified by their hardware serial number which is injecetd via QEMU
(and is thus persistent and predictable). PCI paths are not a reliably
way to identify devices because their availability and numbering depends
on the QEMU machine type.
This change makes the module more robust against changes in QEMU and the
kernel (non-persistent device naming) and by decoupling abstractions
(i.e. rootDevice, bootPartition, and bootLoaderDevice) enables further
improvement down the line.
As with many things, we have scenarios where we don't want to boot on a
disk / bootloader and also we don't want to boot directly.
Sometimes, we want to boot through an OptionROM of our NIC, e.g. netboot
scenarios or let the firmware decide something, e.g. UEFI PXE (or even
UEFI OptionROM!).
This is composed of:
- `directBoot.enable`: whether to direct boot or not
- `directBoot.initrd`: enable overriding the
`config.system.build.initialRamdisk` defaults, useful for
netbootRamdisk for example.
This makes it possible.
Adds a new option to the virtualisation modules that enables specifying explicitly named network interfaces in QEMU VMs.
The existing `virtualisation.vlans` option is still supported for cases where the name of the network interface is irrelevant.
`useEFIBoot` is somewhat misleading, but we should make it possible to
enable UEFI environment / firmware without buying into a bootloader.
This makes it possible.
Previously, it was possible to run with a tmpfs / with
`virtualisation.diskImage = null;`, this was likely broken by my changes
in 4b4e4c3ef9.
It is reintroduced by disabling properly the bootloader for now, as it
is complicated to make it work with.
Now that `useBootLoader` produces a full system image, moving disk
images can be slow because they have a full Nix store in them.
It does not make sense to keep the 9p mountpoint to shadow the
/nix/store of the VM.
We disable it if we have `useBootLoader` and introduce an option for
easy overrides.
This option has been introduced in 678eed323f without realizing there was this
PR inflight, unfortunately, it collide with what this PR does and make
it irrelevant.
Therefore, I remove it here.
The typo creates an empty directory 0755 in initrd rootfs rather than
create the Nix store directories with mode 0755.
I guess setting the mode is not strictly necessary if it worked before
this change, but I'll leave the `-m 0755` in just in case.
...for explicitly named network interfaces
This reverts commit 6ae3e7695e.
(and evaluation fixups 08d26bbb727aed90a969)
Some of the tests fail or time out after the merge.
Adds a new option to the virtualisation modules that enables specifying
explicitly named network interfaces in QEMU VMs. The existing
`virtualisation.vlans` is still supported for cases where the name of
the network interface is irrelevant.
Previously, secrets were named according to the initrd they were
associated with. This created a problem: If secrets were changed whilst
the initrd remained the same, there were two versions of the secrets
with one initrd. The result was that only one version of the secrets would
by recorded into the /boot partition and get used. AFAICT this would
only be the oldest version of the secrets for the given initrd version.
This manifests as #114594, which I found frustrating while trying to use
initrd secrets for the first time. While developing the secrets I found
I could not get new versions of the secrets to take effect.
Additionally, it's a nasty issue to run into if you had cause to change
the initrd secrets for credential rotation, etc, if you change them and
discover you cannot, or alternatively that you can't roll back as you
would expect.
Additional changes in this patch.
* Add a regression test that switching to another grub configuration
with the alternate secrets works. This test relies on the fact that it
is not changing the initrd. I have checked that the test fails if I
undo my change.
* Persist the useBootLoader disk state, similarly to other boot state.
* I had to do this, otherwise I could not find a route to testing the
alternate boot configuration. I did attempt a few different ways of
testing this, including directly running install-grub.pl, but what
I've settled on is most like what a user would do and avoids
depending on lots of internal details.
* Making tests that test the boot are a bit tricky (see hibernate.nix
and installer.nix for inspiration), I found that in addition to
having to copy quite a bit of code I still couldn't get things to
work as desired since the bootloader state was being clobbered.
My change to persist the useBootLoader state could break things,
conceptually. I need some help here discovering if that is the case,
possibly by letting this run through a staging CI if there is one.
Fix#114594.
cc potential reviewers:
@lopsided98 (original implementer) @joachifm (original reviewer),
@wkennington (numerous fixes to grub-install.pl), @lheckemann (wrote
original secrets test).
The aarch64-linux kernel and initrd recently eclipsed 60M, causing the
boot disk image build to run out of space and fail. Double the size of
the image to 120M to fix the issue.
The disk image is stored in expandable qcow2 format, so only the space
actually used by files in the image is consumed. Therefore, other
architectures are not unfairly penalized, and the output size does not
suddenly double.
This also fixes NixOS tests which use this option, like systemd-boot's.
Add a section on ordering option definitions.
Also mention `mkDefault` in the section on `mkOverride`.
Clarify the code a bit by renaming `defaultPriority` to
`defaultOverridePriority` and introducing `defaultOrderPriority`.
This adds an option to the qemu virtualisation module to isolate the
guest's from the host's and outside networks.
This is particularly useful for development sandboxes for example.
The option is disabled by default to preserve the current behaviour.
