nixpkgs/nixos/tests/systemd-oomd.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")
  '';
}