aab534b894
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] bc2188b083dfbbe749a221023e2960b60d4c8951
129 lines
4.3 KiB
Nix
129 lines
4.3 KiB
Nix
# This module allows the test driver to connect to the virtual machine
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# via a root shell attached to port 514.
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{ options, config, lib, pkgs, ... }:
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with lib;
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with import ../../lib/qemu-flags.nix { inherit pkgs; };
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{
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config = {
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systemd.services.backdoor =
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{ wantedBy = [ "multi-user.target" ];
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requires = [ "dev-hvc0.device" "dev-${qemuSerialDevice}.device" ];
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after = [ "dev-hvc0.device" "dev-${qemuSerialDevice}.device" ];
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script =
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''
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export USER=root
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export HOME=/root
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export DISPLAY=:0.0
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source /etc/profile
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# Don't use a pager when executing backdoor
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# actions. Because we use a tty, commands like systemctl
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# or nix-store get confused into thinking they're running
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# interactively.
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export PAGER=
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cd /tmp
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exec < /dev/hvc0 > /dev/hvc0
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while ! exec 2> /dev/${qemuSerialDevice}; do sleep 0.1; done
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echo "connecting to host..." >&2
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stty -F /dev/hvc0 raw -echo # prevent nl -> cr/nl conversion
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echo
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PS1= exec /bin/sh
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'';
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serviceConfig.KillSignal = "SIGHUP";
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};
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# Prevent agetty from being instantiated on the serial device, since it
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# interferes with the backdoor (writes to it will randomly fail
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# with EIO). Likewise for hvc0.
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systemd.services."serial-getty@${qemuSerialDevice}".enable = false;
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systemd.services."serial-getty@hvc0".enable = false;
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# Only use a serial console, no TTY.
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# NOTE: optionalAttrs
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# test-instrumentation.nix appears to be used without qemu-vm.nix, so
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# we avoid defining consoles if not possible.
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# TODO: refactor such that test-instrumentation can import qemu-vm
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# or declare virtualisation.qemu.console option in a module that's always imported
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virtualisation.qemu = {
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consoles = lib.optional (options ? virtualisation.qemu.consoles) qemuSerialDevice;
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package = lib.mkDefault pkgs.qemu_test;
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};
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boot.initrd.preDeviceCommands =
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''
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echo 600 > /proc/sys/kernel/hung_task_timeout_secs
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'';
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boot.initrd.postDeviceCommands =
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''
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# Using acpi_pm as a clock source causes the guest clock to
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# slow down under high host load. This is usually a bad
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# thing, but for VM tests it should provide a bit more
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# determinism (e.g. if the VM runs at lower speed, then
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# timeouts in the VM should also be delayed).
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echo acpi_pm > /sys/devices/system/clocksource/clocksource0/current_clocksource
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'';
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boot.postBootCommands =
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''
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# Panic on out-of-memory conditions rather than letting the
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# OOM killer randomly get rid of processes, since this leads
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# to failures that are hard to diagnose.
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echo 2 > /proc/sys/vm/panic_on_oom
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'';
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# Panic if an error occurs in stage 1 (rather than waiting for
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# user intervention).
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boot.kernelParams =
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[ "console=${qemuSerialDevice}" "panic=1" "boot.panic_on_fail" ];
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# `xwininfo' is used by the test driver to query open windows.
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environment.systemPackages = [ pkgs.xorg.xwininfo ];
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# Log everything to the serial console.
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services.journald.extraConfig =
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''
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ForwardToConsole=yes
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MaxLevelConsole=debug
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'';
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systemd.extraConfig = ''
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# Don't clobber the console with duplicate systemd messages.
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ShowStatus=no
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# Allow very slow start
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DefaultTimeoutStartSec=300
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'';
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boot.consoleLogLevel = 7;
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# Prevent tests from accessing the Internet.
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networking.defaultGateway = mkOverride 150 "";
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networking.nameservers = mkOverride 150 [ ];
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system.requiredKernelConfig = with config.lib.kernelConfig; [
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(isYes "SERIAL_8250_CONSOLE")
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(isYes "SERIAL_8250")
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(isEnabled "VIRTIO_CONSOLE")
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];
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networking.usePredictableInterfaceNames = false;
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# Make it easy to log in as root when running the test interactively.
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users.users.root.initialHashedPassword = mkOverride 150 "";
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services.xserver.displayManager.job.logToJournal = true;
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# Make sure we use the Guest Agent from the QEMU package for testing
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# to reduce the closure size required for the tests.
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services.qemuGuest.package = pkgs.qemu_test.ga;
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};
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}
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