DefaultTimeoutStartSec is normally set to 90 seconds and works fine. But when running NixOS tests on a very slow machine (like a VM without nested virtualisation support) this default is to low and causes systemd units to fail spuriously. One symptom of this issue are tests at times failing with "timed out waiting for the VM to connect". Since the VM connect timeout is 300 seconds I also set DefaultTimeoutStartSec to this which is ridiculously high.
138 lines
4.6 KiB
Nix
138 lines
4.6 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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{ 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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# This option is a dummy that if used in conjunction with
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# modules/virtualisation/qemu-vm.nix gets merged with the same option defined
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# there and only is declared here because some modules use
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# test-instrumentation.nix but not qemu-vm.nix.
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#
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# One particular example are the boot tests where we want instrumentation
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# within the images but not other stuff like setting up 9p filesystems.
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options.virtualisation.qemu.program = mkOption { type = types.path; };
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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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virtualisation.qemu.consoles = [ qemuSerialDevice ];
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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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# Coverage data is written into /tmp/coverage-data.
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mkdir -p /tmp/xchg/coverage-data
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'';
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# If the kernel has been built with coverage instrumentation, make
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# it available under /proc/gcov.
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boot.kernelModules = [ "gcov-proc" ];
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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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systemd.globalEnvironment.GCOV_PREFIX = "/tmp/xchg/coverage-data";
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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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# set default stateVersion to avoid warnings during eval
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system.stateVersion = mkDefault "18.03";
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};
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}
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