nixpkgs/nixos/modules/testing/test-instrumentation.nix
aszlig 00934bb908
nixos/tests: Revert setting min_free_kbytes
This reverts commit 02b568414d.

With a5bc11f and 6353f58 in place, we really don't need this anymore.

After running about 500 VM tests on my Hydra, it still didn't improve
very much.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
2015-12-14 17:40:28 +01:00

111 lines
3.5 KiB
Nix

# This module allows the test driver to connect to the virtual machine
# via a root shell attached to port 514.
{ config, lib, pkgs, ... }:
with lib;
let kernel = config.boot.kernelPackages.kernel; in
{
config = {
systemd.services.backdoor =
{ wantedBy = [ "multi-user.target" ];
requires = [ "dev-hvc0.device" "dev-ttyS0.device" ];
after = [ "dev-hvc0.device" "dev-ttyS0.device" ];
script =
''
export USER=root
export HOME=/root
export DISPLAY=:0.0
source /etc/profile
cd /tmp
exec < /dev/hvc0 > /dev/hvc0
while ! exec 2> /dev/ttyS0; do sleep 0.1; done
echo "connecting to host..." >&2
stty -F /dev/hvc0 raw -echo # prevent nl -> cr/nl conversion
echo
PS1= exec /bin/sh
'';
serviceConfig.KillSignal = "SIGHUP";
};
# Prevent agetty from being instantiated on ttyS0, since it
# interferes with the backdoor (writes to ttyS0 will randomly fail
# with EIO). Likewise for hvc0.
systemd.services."serial-getty@ttyS0".enable = false;
systemd.services."serial-getty@hvc0".enable = false;
# Don't use a pager when executing backdoor actions. Because we
# use a tty, commands like systemctl or nix-store get confused
# into thinking they're running interactively.
environment.variables.PAGER = "";
boot.initrd.postDeviceCommands =
''
# Using acpi_pm as a clock source causes the guest clock to
# slow down under high host load. This is usually a bad
# thing, but for VM tests it should provide a bit more
# determinism (e.g. if the VM runs at lower speed, then
# timeouts in the VM should also be delayed).
echo acpi_pm > /sys/devices/system/clocksource/clocksource0/current_clocksource
'';
boot.postBootCommands =
''
# Panic on out-of-memory conditions rather than letting the
# OOM killer randomly get rid of processes, since this leads
# to failures that are hard to diagnose.
echo 2 > /proc/sys/vm/panic_on_oom
# Coverage data is written into /tmp/coverage-data.
mkdir -p /tmp/xchg/coverage-data
'';
# If the kernel has been built with coverage instrumentation, make
# it available under /proc/gcov.
boot.kernelModules = [ "gcov-proc" ];
# Panic if an error occurs in stage 1 (rather than waiting for
# user intervention).
boot.kernelParams =
[ "console=ttyS0" "panic=1" "boot.panic_on_fail" ];
# `xwininfo' is used by the test driver to query open windows.
environment.systemPackages = [ pkgs.xorg.xwininfo ];
# Log everything to the serial console.
services.journald.extraConfig =
''
ForwardToConsole=yes
MaxLevelConsole=debug
'';
# Don't clobber the console with duplicate systemd messages.
systemd.extraConfig = "ShowStatus=no";
boot.consoleLogLevel = 7;
# Prevent tests from accessing the Internet.
networking.defaultGateway = mkOverride 150 "";
networking.nameservers = mkOverride 150 [ ];
systemd.globalEnvironment.GCOV_PREFIX = "/tmp/xchg/coverage-data";
system.requiredKernelConfig = with config.lib.kernelConfig; [
(isYes "SERIAL_8250_CONSOLE")
(isYes "SERIAL_8250")
(isEnabled "VIRTIO_CONSOLE")
];
networking.usePredictableInterfaceNames = false;
# Make it easy to log in as root when running the test interactively.
users.extraUsers.root.initialHashedPassword = mkOverride 150 "";
};
}