cleanup: organize buildkite files, add a test role

Author: johnalotoski

nix/metal/bitteProfile/auto-gc.nix renamed to nix/metal/bitteProfile/buildkite/auto-gc.nix

@@ -12,6 +12,8 @@
 in
   with lib; {
     imports = [
+      # Common host level config (also applied at guest level)
+      ./common.nix
       # GC only from the host to avoid duplicating GC in containers
       ./auto-gc.nix
       # Docker module required in both the host and guest containers
@@ -127,7 +129,10 @@ in
 
           config = {
             imports = [
+              # Common guest level config (also applied at host level)
               ./common.nix
+
+              # Prevent nix sandbox related failures
               ./nix_nsswitch.nix
 
               # Docker module required in both the host and guest containers

nix/metal/bitteProfile/buildkite-agent-containers.nix renamed to nix/metal/bitteProfile/buildkite/buildkite-agent-containers.nix

@@ -508,10 +508,38 @@ in {
             ++ (baseEquinixMachineConfig "equinix-1")
             ++ buildkiteOnly
             ++ [
-              ./buildkite-agent-containers.nix
-              ./common.nix
-              ({lib, ...}: {
-              })
+              ./buildkite/buildkite-agent-containers.nix
+              (
+                {
+                  config,
+                  lib,
+                  ...
+                }: let
+                  cfg = config.services.buildkite-containers;
+                in {
+                  services.auto-gc = {
+                    nixAutoMaxFreedGB = 150;
+                    nixAutoMinFreeGB = 90;
+                    nixHourlyMaxFreedGB = 600;
+                    nixHourlyMinFreeGB = 150;
+                    nixWeeklyGcFull = true;
+                    nixWeeklyGcOnCalendar = "Sat *-*-* 20:00:00";
+                  };
+
+                  services.buildkite-containers.containerList = let
+                    mkContainer = n: prio: {
+                      containerName = "ci${cfg.hostIdSuffix}-${toString n}";
+                      guestIp = "10.254.1.1${toString n}";
+                      inherit prio;
+                      tags = {
+                        system = "x86_64-linux";
+                        queue = "test";
+                      };
+                    };
+                  in
+                    map (n: mkContainer n (toString (10 - n))) (lib.range 1 5);
+                }
+              )
             ];
         };
       };