nixpkgs/nixos/tests/systemd-oomd.nix

import ./make-test-python.nix ({ pkgs, ... }:

{
  name = "systemd-oomd";

  # This test is a simplified version of systemd's testsuite-55.
  # https://github.com/systemd/systemd/blob/v251/test/units/testsuite-55.sh
  nodes.machine = { pkgs, ... }: {
    # Limit VM resource usage.
    virtualisation.memorySize = 1024;
    systemd.oomd.extraConfig.DefaultMemoryPressureDurationSec = "1s";

    systemd.slices.workload = {
      description = "Test slice for memory pressure kills";
      sliceConfig = {
        MemoryAccounting = true;
        ManagedOOMMemoryPressure = "kill";
        ManagedOOMMemoryPressureLimit = "10%";
      };
    };

    systemd.services.testbloat = {
      description = "Create a lot of memory pressure";
      serviceConfig = {
        Slice = "workload.slice";
        MemoryHigh = "5M";
        ExecStart = "${pkgs.coreutils}/bin/tail /dev/zero";
      };
    };

    systemd.services.testchill = {
      description = "No memory pressure";
      serviceConfig = {
        Slice = "workload.slice";
        MemoryHigh = "3M";
        ExecStart = "${pkgs.coreutils}/bin/sleep infinity";
      };
    };
  };

  testScript = ''
    # Start the system.
    machine.wait_for_unit("multi-user.target")
    machine.succeed("oomctl")

    machine.succeed("systemctl start testchill.service")
    with subtest("OOMd should kill the bad service"):
        machine.fail("systemctl start --wait testbloat.service")
        assert machine.get_unit_info("testbloat.service")["Result"] == "oom-kill"

    with subtest("Service without memory pressure should be untouched"):
        machine.require_unit_state("testchill.service", "active")
  '';
})