The env var approach caps out at 128K which makes large test scripts fail checks with:
```
error: executing '.../bin/bash': Argument list too long
```
The script already exists in the store, let's use that.
In 9e78baf, Aarch64 machines were added the `-device virtio-gpu-pci`
argument, to mirror `-vga std` option that was added unconditionally to
virtualised x86_64 machines. This also enabled screenshots on aarch64
machines to be taken in tests. Since then, in a7ca287, the `-vga std`
option was removed, because that is the default value of this option
embedded in QEMU since version 2.2.
Removing it from the hard-coded list of qemu options makes it possible
for the user to choose their own `-vga` value. Similarly, for Aarch
virtualised machines, choosing unconditionally the `-device virtio-gpu-pci`
option instead of e.g `-device virtio-gpu-gl-pci`, can be bothersome too - see:
https://discourse.nixos.org/t/test-an-aarch64-linux-vm-wayland-compositor-from-an-x86-64-linux-host/77416/2
This commit is similar to 44c6c2ef16 which
was reverted in #527048.
After d95261b435, the following flake.nix fails:
```nix
{
inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
outputs = { nixpkgs, ... }: {
nixosConfigurations.demo = nixpkgs.lib.nixosSystem {
system = "x86_64-linux";
modules = [
({ lib, ... }: {
boot.loader.grub.enable = false;
fileSystems."/" = { device = "none"; fsType = "tmpfs"; };
nixpkgs.config.packageOverrides =
lib.mkIf false (_: { });
})
];
};
};
}
```
This is the error:
```
$ nix build /tmp/tmp.vWEVitTgK9/#nixosConfigurations.demo.config.system.build.toplevel
evaluation warning: system.stateVersion is not set, defaulting to 26.05. Read why this matters on https://nixos.org/manual/nixos/stable/options.html#opt-system.stateVersion.
error:
… while calling the 'derivationStrict' builtin
at <nix/derivation-internal.nix>:37:12:
36|
37| strict = derivationStrict drvAttrs;
| ^
38|
… while evaluating derivation 'nixos-system-nixos-26.05.20260409.4c1018d'
whose name attribute is located at /nix/store/anvdcc2arw7kqrvwnidvhw6ypkkvws68-source/pkgs/stdenv/generic/make-derivation.nix:541:11
… while evaluating attribute 'buildCommand' of derivation 'nixos-system-nixos-26.05.20260409.4c1018d'
at /nix/store/anvdcc2arw7kqrvwnidvhw6ypkkvws68-source/nixos/modules/system/activation/top-level.nix:64:7:
63| passAsFile = [ "extraDependencies" ];
64| buildCommand = systemBuilder;
| ^
65|
… while evaluating the option `environment.etc.dbus-1.source':
… while evaluating the default value of option `pythonTestDriverPackage`
… while evaluating the module argument `hostPkgs' in "/nix/store/anvdcc2arw7kqrvwnidvhw6ypkkvws68-source/nixos/lib/testing/driver.nix":
… noting that argument `hostPkgs` is not externally provided, so querying `_module.args` instead, requiring `config`
… while evaluating the option `hostPkgs':
(stack trace truncated; use '--show-trace' to show the full, detailed trace)
error: The option `hostPkgs' was accessed but has no value defined. Try setting the option.
```
Setting a `defaultText` fixes the issue.
I've also added a regression test under `nixos/tests/nixos-test-driver/` and
fixed a typo in the option description ("implemetnation").
ignore the NixOS configuration's hostname and only use the test driver
attribute for the type hints. This allows for setting a different host
name than the node name in the test without trigggering type errors in
the typecheck phase.
co-authored-by: phanirithvij <phanirithvij2000@gmail.com>
`vhost-device-vsock`[1] is a custom implementation of AF_VSOCK, but the
application on the host-side uses a UNIX domain-socket. This gives us
the following nice properties:
* We don't need to do `--arg sandbox-paths /dev/vhost-vsock` anymore for
debugging builds within the sandbox. That means, untrusted users can
also debug these kinds of tests now.
* This prevents CID conflicts on the host-side, i.e. there's no need for
using `sshBackdoor.vsockOffset` for tests anymore.
A big shout-out goes to Allison Karlitskaya, the developer of test.thing[2]
who talked about this approach to do AF_VSOCK on All Systems Go 2025.
This patch requires systemd 258[3] because this contains `vhost-mux` in
its SSH config which is needed to connect to the VMs from now on.
To not blow up the patches even more, this only uses AF_VSOCK for the
debugger. A potential follow-up for the future would be a removal of the
current `backdoor.service` and replace it entirely by this
functionality.
The internal implementation tries to be consistent with how VLANs and
machines are handled, i.e. the processes are started when the Driver's
context is entered and cleaned up in __exit__().
I decided to push the process management and creation of sockets for
vhost-device-vsock into its own class, that's an implementation detail
and not a concern for the test-driver. In fact, `vhost-device-vsock` is
something we can drop once QEMU implements native support for using
AF_UNIX on the host-side[4]. `VsockPair` is its own class since
returning e.g. a triple of `(Path, Path, Int)` would be ambiguous in
what is the guest and what the host path (and frankly, I found it hard
to distinguish the two when reading the docs of `vhost-device-vsock`
initially).
Finally, now that we can do the SSH backdoor without adding additional
devices to the sandbox, I figured, it's time to write a test-case for
it.
[1] https://github.com/rust-vmm/vhost-device/blob/main/vhost-device-vsock/README.md
[2] https://codeberg.org/lis/test.thing
[3] https://github.com/NixOS/nixpkgs/pull/427968
[4] https://gitlab.com/qemu-project/qemu/-/issues/2095
Format all Nix files using the officially approved formatter,
making the CI check introduced in the previous commit succeed:
nix-build ci -A fmt.check
This is the next step of the of the [implementation](https://github.com/NixOS/nixfmt/issues/153)
of the accepted [RFC 166](https://github.com/NixOS/rfcs/pull/166).
This commit will lead to merge conflicts for a number of PRs,
up to an estimated ~1100 (~33%) among the PRs with activity in the past 2
months, but that should be lower than what it would be without the previous
[partial treewide format](https://github.com/NixOS/nixpkgs/pull/322537).
Merge conflicts caused by this commit can now automatically be resolved while rebasing using the
[auto-rebase script](8616af08d9/maintainers/scripts/auto-rebase).
If you run into any problems regarding any of this, please reach out to the
[formatting team](https://nixos.org/community/teams/formatting/) by
pinging @NixOS/nix-formatting.
Since the debut of the test-driver, we didn't obtain
a race timer with the test execution to ensure that tests doesn't run beyond
a certain amount of time.
This is particularly important when you are running into hanging tests
which cannot be detected by current facilities (requires more pvpanic wiring up, QMP
API stuff, etc.).
Two easy examples:
- Some QEMU tests may get stuck in some situation and run for more than 24 hours → we default to 1 hour max.
- Some QEMU tests may panic in the wrong place, e.g. UEFI firmware or worse → end users can set a "reasonable" amount of time
And then, we should let the retry logic retest them until they succeed and adjust
their global timeouts.
Of course, this does not help with the fact that the timeout may need to be
a function of the actual busyness of the machine running the tests.
This is only one step towards increased reliability.
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.
...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.
This is a decomposition of the testing-python.nix and build-vms.nix
files into modules.
By refactoring the glue, we accomplish the following:
- NixOS tests can now use `imports` and other module system features.
- Network-wide test setup can now be reusable; example:
- A setup with all VMs configured to use a DNS server
- Split long, slow tests into multiple tests that import a
common module that has most of the setup.
- Type checking for the test arguments
- (TBD) "generated" options reference docs
- Aspects that had to be wired through all the glue are now in their
own files.
- Chief example: interactive.nix.
- Also: network.nix
In rewriting this, I've generally stuck as close as possible to the
existing code; copying pieces of logic and rewiring them, without
changing the logic itself.
I've made two exceptions to this rule
- Introduction of `extraDriverArgs` instead of hardcoded
interactivity logic.
- Incorporation of https://github.com/NixOS/nixpkgs/pull/144110
in testScript.nix.
I might revert the latter and split it into a new commit.
