diff --git a/cluster/default.nix b/cluster/default.nix
index 97ab73c..54a8969 100644
--- a/cluster/default.nix
+++ b/cluster/default.nix
@@ -16,6 +16,8 @@ lib.evalModules {
     ./lib/port-magic-multi.nix
     ./lib/mesh.nix
     ./lib/secrets.nix
+    ./lib/testing.nix
+    ./lib/lib.nix
 
     ./import-services.nix
   ];
diff --git a/cluster/lib/inject-nixos-config.nix b/cluster/lib/inject-nixos-config.nix
index 6e5add1..4523b96 100644
--- a/cluster/lib/inject-nixos-config.nix
+++ b/cluster/lib/inject-nixos-config.nix
@@ -2,9 +2,9 @@
 with lib;
 
 {
-  options.out.injectNixosConfig = mkOption {
-    description = "NixOS configuration to inject into the given host.";
-    type = with types; functionTo raw;
+  options.out = mkOption {
+    description = "Output functions.";
+    type = with types; lazyAttrsOf (functionTo raw);
     default = const [];
   };
 }
diff --git a/cluster/lib/lib.nix b/cluster/lib/lib.nix
new file mode 100644
index 0000000..1aedf13
--- /dev/null
+++ b/cluster/lib/lib.nix
@@ -0,0 +1,12 @@
+{ config, lib, ... }:
+
+{
+  options.lib = {
+    forService = lib.mkOption {
+      description = "Enable these definitions for a particular service only.";
+      type = lib.types.functionTo lib.types.raw;
+      readOnly = true;
+      default = service: lib.mkIf (!config.simulacrum || lib.any (s: s == service) config.testConfig.activeServices);
+    };
+  };
+}
diff --git a/cluster/lib/service-module.nix b/cluster/lib/service-module.nix
index 3ef8c98..2fb07e7 100644
--- a/cluster/lib/service-module.nix
+++ b/cluster/lib/service-module.nix
@@ -52,6 +52,24 @@ in
       }));
       default = {};
     };
+    simulacrum = {
+      enable = mkEnableOption "testing this service in the Simulacrum";
+      deps = mkOption {
+        description = "Other services to include.";
+        type = with types; listOf str;
+        default = [];
+      };
+      settings = mkOption {
+        description = "NixOS test configuration.";
+        type = types.deferredModule;
+        default = {};
+      };
+      augments = mkOption {
+        description = "Cluster augments (will be propagated).";
+        type = types.deferredModule;
+        default = {};
+      };
+    };
   };
   config.otherNodes = builtins.mapAttrs (const filterGroup) config.nodes;
 }
diff --git a/cluster/lib/services.nix b/cluster/lib/services.nix
index b500f1b..4e9f8bc 100644
--- a/cluster/lib/services.nix
+++ b/cluster/lib/services.nix
@@ -39,7 +39,11 @@ in
     default = {};
   };
 
-  config.out.injectNixosConfig = hostName: (lib.flatten (lib.mapAttrsToList (getHostConfigurations hostName) config.services)) ++ [
-    introspectionModule
-  ];
+  config.out = {
+    injectNixosConfigForServices = services: hostName: (lib.flatten (lib.mapAttrsToList (getHostConfigurations hostName) (lib.getAttrs services config.services))) ++ [
+      introspectionModule
+    ];
+
+    injectNixosConfig = config.out.injectNixosConfigForServices (lib.attrNames config.services);
+  };
 }
diff --git a/cluster/lib/testing.nix b/cluster/lib/testing.nix
new file mode 100644
index 0000000..90c9106
--- /dev/null
+++ b/cluster/lib/testing.nix
@@ -0,0 +1,15 @@
+{ lib, ... }:
+
+{
+  options = {
+    simulacrum = lib.mkOption {
+      description = "Whether we are in the Simulacrum.";
+      type = lib.types.bool;
+      default = false;
+    };
+    testConfig = lib.mkOption {
+      type = lib.types.attrs;
+      readOnly = true;
+    };
+  };
+}
diff --git a/cluster/part.nix b/cluster/part.nix
index eae3222..58e93b3 100644
--- a/cluster/part.nix
+++ b/cluster/part.nix
@@ -3,6 +3,7 @@
 {
   imports = [
     ./catalog
+    ./simulacrum/checks.nix
   ];
 
   options.cluster = lib.mkOption {
diff --git a/cluster/services/wireguard/default.nix b/cluster/services/wireguard/default.nix
index a1f25eb..b3ba747 100644
--- a/cluster/services/wireguard/default.nix
+++ b/cluster/services/wireguard/default.nix
@@ -10,6 +10,19 @@ let
   };
 
   getExtAddr = host: host.interfaces.primary.addrPublic;
+
+  snakeoilPublicKeys = {
+    checkmate = "TESTtbFybW5YREwtd18a1A4StS4YAIUS5/M1Lv0jHjA=";
+    grail = "TEsTh7bthkaDh9A1CpqDi/F121ao5lRZqIJznLH8mB4=";
+    thunderskin = "tEST6afFmVN18o+EiWNFx+ax3MJwdQIeNfJSGEpffXw=";
+    VEGAS = "tEsT6s7VtM5C20eJBaq6UlQydAha8ATlmrTRe9T5jnM=";
+    prophet = "TEstYyb5IoqSL53HbSQwMhTaR16sxcWcMmXIBPd+1gE=";
+  };
+
+  grease = hourName: realPublicKey: if config.simulacrum then
+    snakeoilPublicKeys.${hourName}
+  else
+    realPublicKey;
 in
 {
   vars = {
@@ -22,7 +35,7 @@ in
       extra = {
         meshIp = "10.1.1.32";
         inherit meshNet;
-        pubKey = "fZMB9CDCWyBxPnsugo3Uxm/TIDP3VX54uFoaoC0bP3U=";
+        pubKey = grease "checkmate" "fZMB9CDCWyBxPnsugo3Uxm/TIDP3VX54uFoaoC0bP3U=";
         extraRoutes = [];
       };
     };
@@ -31,7 +44,7 @@ in
       extra = {
         meshIp = "10.1.1.6";
         inherit meshNet;
-        pubKey = "0WAiQGdWySsGWFUk+a9e0I+BDTKwTyWQdFT2d7BMfDQ=";
+        pubKey = grease "grail" "0WAiQGdWySsGWFUk+a9e0I+BDTKwTyWQdFT2d7BMfDQ=";
         extraRoutes = [];
       };
     };
@@ -40,7 +53,7 @@ in
       extra = {
         meshIp = "10.1.1.4";
         inherit meshNet;
-        pubKey = "xvSsFvCVK8h2wThZJ7E5K0fniTBIEIYOblkKIf3Cwy0=";
+        pubKey = grease "thunderskin" "xvSsFvCVK8h2wThZJ7E5K0fniTBIEIYOblkKIf3Cwy0=";
         extraRoutes = [];
       };
     };
@@ -49,7 +62,7 @@ in
       extra = {
         meshIp = "10.1.1.5";
         inherit meshNet;
-        pubKey = "NpeB8O4erGTas1pz6Pt7qtY9k45YV6tcZmvvA4qXoFk=";
+        pubKey = grease "VEGAS" "NpeB8O4erGTas1pz6Pt7qtY9k45YV6tcZmvvA4qXoFk=";
         extraRoutes = [ "${hours.VEGAS.interfaces.vstub.addr}/32" "10.10.0.0/16" ];
       };
     };
@@ -58,7 +71,7 @@ in
       extra = {
         meshIp = "10.1.1.9";
         inherit meshNet;
-        pubKey = "MMZAbRtNE+gsLm6DJy9VN/Y39E69oAZnvOcFZPUAVDc=";
+        pubKey = grease "prophet" "MMZAbRtNE+gsLm6DJy9VN/Y39E69oAZnvOcFZPUAVDc=";
         extraRoutes = [];
       };
     };
@@ -69,12 +82,20 @@ in
       storm = [ "VEGAS" ];
     };
     nixos = {
-      mesh = ./mesh.nix;
-      storm = ./storm.nix;
+      mesh = [
+        ./mesh.nix
+      ] ++ lib.optionals config.simulacrum [
+        ./simulacrum/snakeoil-keys.nix
+      ];
+      storm = [ ./storm.nix ];
     };
     secrets.meshPrivateKey = {
       nodes = config.services.wireguard.nodes.mesh;
       shared = false;
     };
+    simulacrum = {
+      enable = true;
+      settings = ./test.nix;
+    };
   };
 }
diff --git a/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-VEGAS b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-VEGAS
new file mode 100644
index 0000000..e15616d
--- /dev/null
+++ b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-VEGAS
@@ -0,0 +1 @@
+MNvWpMluuzQvPyGTp7jtyPSyz6n9lIly/WX1gW2NAHg=
diff --git a/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-checkmate b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-checkmate
new file mode 100644
index 0000000..f498b5b
--- /dev/null
+++ b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-checkmate
@@ -0,0 +1 @@
+YHzP8rBP6qiXs6ZdnvHop9KnCYRADIEejwZzAzvj8m4=
diff --git a/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-grail b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-grail
new file mode 100644
index 0000000..7496093
--- /dev/null
+++ b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-grail
@@ -0,0 +1 @@
+uD7X5E6N9d0sN+xPr/bWnehSa3bAok741GO7Z4I+Z3I=
diff --git a/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-prophet b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-prophet
new file mode 100644
index 0000000..d46aa5e
--- /dev/null
+++ b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-prophet
@@ -0,0 +1 @@
+QHyIJ3HoKGGFN28qOrQP4UyoQMP5bM7Idn2MzayKzEM=
diff --git a/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-thunderskin b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-thunderskin
new file mode 100644
index 0000000..6088510
--- /dev/null
+++ b/cluster/services/wireguard/simulacrum/keys/snakeoilPrivateKey-thunderskin
@@ -0,0 +1 @@
+YLl+hkWaCWx/5PpWs3cQ+bKqYdJef/qZ+FMTsM9ammM=
diff --git a/cluster/services/wireguard/simulacrum/snakeoil-keys.nix b/cluster/services/wireguard/simulacrum/snakeoil-keys.nix
new file mode 100644
index 0000000..d3dd500
--- /dev/null
+++ b/cluster/services/wireguard/simulacrum/snakeoil-keys.nix
@@ -0,0 +1,6 @@
+{ lib, config, ... }: {
+  config.environment.etc = {
+    "dummy-secrets/cluster-wireguard-meshPrivateKey".source = lib.mkForce ./keys/snakeoilPrivateKey-${config.networking.hostName};
+    "dummy-secrets/wireguard-key-storm".source = lib.mkForce ./keys/snakeoilPrivateKey-${config.networking.hostName};
+  };
+}
diff --git a/cluster/services/wireguard/test.nix b/cluster/services/wireguard/test.nix
new file mode 100644
index 0000000..dfa7e92
--- /dev/null
+++ b/cluster/services/wireguard/test.nix
@@ -0,0 +1,26 @@
+{ cluster, lib, ... }:
+
+{
+  testScript = ''
+    start_all()
+    ${lib.pipe cluster.config.services.wireguard.nodes.mesh [
+      (map (node: /*python*/ ''
+        ${node}.wait_for_unit("wireguard-wgmesh.target")
+      ''))
+      (lib.concatStringsSep "\n")
+    ]}
+
+    ${lib.pipe cluster.config.services.wireguard.nodes.mesh [
+      (map (node: /*python*/ ''
+        with subtest("${node} can reach all other nodes"):
+          ${lib.pipe (cluster.config.services.wireguard.otherNodes.mesh node) [
+            (map (peer: /*python*/ ''
+              ${node}.succeed("ping -c3 ${cluster.config.hostLinks.${peer}.mesh.extra.meshIp}")
+            ''))
+            (lib.concatStringsSep "\n  ")
+          ]}
+      ''))
+      (lib.concatStringsSep "\n")
+    ]}
+  '';
+}
diff --git a/cluster/simulacrum/checks.nix b/cluster/simulacrum/checks.nix
new file mode 100644
index 0000000..bf3e918
--- /dev/null
+++ b/cluster/simulacrum/checks.nix
@@ -0,0 +1,16 @@
+{ config, extendModules, lib, ... }:
+
+{
+  perSystem = { pkgs, system, ... }: {
+    checks = lib.mkIf (system == "x86_64-linux") (lib.mapAttrs' (name: svc: let
+      runSimulacrum = pkgs.callPackage ./. {
+        inherit config extendModules;
+      };
+    in {
+      name = "simulacrum-${name}";
+      value = runSimulacrum {
+        service = name;
+      };
+    }) (lib.filterAttrs (_: svc: svc.simulacrum.enable) config.cluster.config.services));
+  };
+}
diff --git a/cluster/simulacrum/default.nix b/cluster/simulacrum/default.nix
new file mode 100644
index 0000000..26eca7e
--- /dev/null
+++ b/cluster/simulacrum/default.nix
@@ -0,0 +1,134 @@
+{ testers, config, extendModules, lib, system }:
+
+{ service }:
+
+let
+  serviceConfig = config.cluster.config.services.${service};
+  serviceList = getDepsRecursive [] service;
+  allAugments = map (svc: config.cluster.config.services.${svc}.simulacrum.augments) serviceList;
+
+  getDepsRecursive = acc: service: let
+    deps = lib.subtractLists acc config.cluster.config.services.${service}.simulacrum.deps;
+    acc' = acc ++ [ service ];
+    recurse = getDepsRecursive acc';
+  in lib.unique (lib.flatten ([ service ] ++ map recurse deps));
+
+  lift = config;
+
+  snakeoil = {
+    ssh = {
+      public = lib.fileContents ../../packages/checks/snakeoil/ssh/snakeoil-key.pub;
+      private = ../../packages/checks/snakeoil/ssh/snakeoil-key;
+    };
+  };
+
+  nodes = lib.attrNames config.gods.fromLight;
+  nodes' = lib.attrNames (config.gods.fromLight // { nowhere = null; });
+  digits = lib.attrsets.listToAttrs (lib.zipListsWith lib.nameValuePair nodes' (lib.range 1 255));
+  depot' = extendModules {
+    modules = [
+      ({ config, ... }: {
+        gods.fromLight = lib.mapAttrs (name: cfg: {
+          interfaces.primary = {
+            link = lib.mkForce "vprimary";
+          };
+          ssh.id.publicKey = lib.mkForce snakeoil.ssh.public;
+        }) lift.gods.fromLight;
+
+        cluster = lib.mkForce (lift.cluster.extendModules {
+          specialArgs.depot = config;
+          modules = [
+            {
+              simulacrum = true;
+              testConfig = {
+                subject = service;
+                activeServices = serviceList;
+              };
+            }
+          ];
+        });
+      })
+    ];
+  };
+  specialArgs = depot'.config.lib.summon system lib.id;
+in
+
+testers.runNixOSTest {
+  name = "simulacrum-${service}";
+
+  imports = [
+    serviceConfig.simulacrum.settings
+    ./nowhere
+    {
+      nodes.nowhere.imports = [
+        config.flake.nixosModules.port-magic
+      ];
+    }
+  ] ++ allAugments;
+
+  _module.args = {
+    inherit (depot'.config) cluster;
+  };
+
+  node = { inherit specialArgs; };
+  nodes = lib.genAttrs nodes (node: let
+    hour = depot'.config.hours.${node};
+  in {
+    imports = [
+      specialArgs.depot.hours.${node}.nixos
+      ../../packages/checks/modules/nixos/age-dummy-secrets
+      ../../packages/checks/modules/nixos/external-storage.nix
+    ] ++ depot'.config.cluster.config.out.injectNixosConfigForServices serviceList node;
+
+    boot.kernel.sysctl."net.ipv4.ip_forward" = "1";
+    networking = {
+      interfaces = {
+        ${hour.interfaces.primary.link} = {
+          useDHCP = lib.mkForce false;
+          virtual = true;
+          ipv4.addresses = lib.mkForce ([
+            {
+              address = hour.interfaces.primary.addr;
+              prefixLength = 32;
+            }
+          ] ++ lib.optional hour.interfaces.primary.isNat {
+            address = hour.interfaces.primary.addrPublic;
+            prefixLength = 32;
+          });
+        };
+        eth1.ipv4.routes = lib.pipe nodes [
+          (lib.filter (n: n != node))
+          (map (n: let
+            hour = depot'.config.hours.${n};
+          in {
+            address = hour.interfaces.primary.addrPublic;
+            prefixLength = 32;
+            via = "192.168.1.${toString digits.${n}}";
+          }))
+        ];
+      };
+
+      firewall.extraCommands = lib.mkAfter (lib.optionalString (hour.interfaces.primary.isNat) ''
+        # self-nat
+        iptables -t nat -A PREROUTING -d ${hour.interfaces.primary.addrPublic} -j DNAT --to-destination ${hour.interfaces.primary.addr}
+        iptables -t nat -A OUTPUT -d ${hour.interfaces.primary.addrPublic} -j DNAT --to-destination ${hour.interfaces.primary.addr}
+        iptables -t nat -A POSTROUTING -s ${hour.interfaces.primary.addr} -j SNAT --to-source ${hour.interfaces.primary.addrPublic}
+      '');
+    };
+
+    systemd.services = {
+      hyprspace.enable = false;
+    };
+
+    environment.etc = {
+      "ssh/ssh_host_ed25519_key" = {
+        source = snakeoil.ssh.private;
+        mode = "0400";
+      };
+    };
+    virtualisation = {
+      cores = 2;
+      memorySize = 4096;
+    };
+  });
+}
diff --git a/cluster/simulacrum/nowhere/default.nix b/cluster/simulacrum/nowhere/default.nix
new file mode 100644
index 0000000..4e3aaaf
--- /dev/null
+++ b/cluster/simulacrum/nowhere/default.nix
@@ -0,0 +1,101 @@
+{ cluster, config, lib, pkgs, ... }:
+
+let
+  lift = config;
+
+  cfsslConfigIntermediateCA = pkgs.writeText "simulacrum-cfssl-config.json" (builtins.toJSON {
+    signing = {
+      default.expiry = "8760h";
+      profiles.intermediate = {
+        expiry = "8760h";
+        usages = [
+          "cert sign"
+          "crl sign"
+        ];
+        ca_constraint = {
+          is_ca = true;
+          max_path_len = 1;
+        };
+      };
+    };
+  });
+
+  caCsr = pkgs.writeText "simulacrum-ca-csr.json" (builtins.toJSON {
+    CN = "Simulacrum Root CA";
+  });
+
+  ca = pkgs.runCommand "simulacrum-snakeoil-ca" {
+    nativeBuildInputs = [
+      pkgs.cfssl
+    ];
+  } ''
+    mkdir $out
+    cfssl gencert --initca ${caCsr} | cfssljson --bare $out/ca
+  '';
+
+  genCert = extraFlags: csrData: let
+    csr = pkgs.writeText "simulacrum-csr.json" (builtins.toJSON csrData);
+  in pkgs.runCommand "simulacrum-snakeoil-cert" {
+    nativeBuildInputs = [
+      pkgs.cfssl
+    ];
+  } ''
+    mkdir $out
+    cfssl gencert ${lib.escapeShellArgs ([
+      "--ca=file:${ca}/ca.pem"
+      "--ca-key=file:${ca}/ca-key.pem"
+    ] ++ extraFlags ++ [
+      csr
+    ])} | cfssljson --bare $out/cert
+  '';
+
+  genHostCert = hostname: genCert [ "--hostname=${hostname}" ] { CN = hostname; };
+
+  getNodeAddr = node: (builtins.head config.nodes.${node}.networking.interfaces.eth1.ipv4.addresses).address;
+in
+
+{
+  imports = [
+    ./options.nix
+  ];
+  defaults = {
+    networking.hosts."${getNodeAddr "nowhere"}" = lib.attrNames config.nowhere.names;
+    security.pki.certificateFiles = [
+      "${ca}/ca.pem"
+    ];
+  };
+
+  nowhere.certs = {
+    inherit ca;
+    intermediate = genCert [ "--config=${cfsslConfigIntermediateCA}" "--profile=intermediate" ] {
+      CN = "Simulacrum Intermediate CA";
+    };
+  };
+
+  nodes.nowhere = { config, depot, ... }: {
+    networking = {
+      firewall.allowedTCPPorts = [ 443 ];
+      interfaces.eth1.ipv4.routes = lib.mapAttrsToList (name: hour: {
+        address = hour.interfaces.primary.addrPublic;
+        prefixLength = 32;
+        via = getNodeAddr name;
+      }) depot.gods.fromLight;
+      nameservers = map (name: depot.hours.${name}.interfaces.primary.addrPublic) cluster.config.services.dns.nodes.authoritative;
+    };
+    services.nginx = {
+      enable = true;
+      recommendedProxySettings = true;
+      virtualHosts = lib.mapAttrs (name: link: let
+        cert = genHostCert name;
+      in {
+        forceSSL = true;
+        sslCertificate = "${cert}/cert.pem";
+        sslCertificateKey = "${cert}/cert-key.pem";
+        locations."/" = {
+          proxyPass = config.links.${link}.url;
+          extraConfig = "proxy_ssl_verify off;";
+        };
+      }) lift.nowhere.names;
+    };
+  };
+}
diff --git a/cluster/simulacrum/nowhere/options.nix b/cluster/simulacrum/nowhere/options.nix
new file mode 100644
index 0000000..b0420b6
--- /dev/null
+++ b/cluster/simulacrum/nowhere/options.nix
@@ -0,0 +1,16 @@
+{ lib, ... }:
+
+{
+  options.nowhere = {
+    names = lib.mkOption {
+      description = "Hostnames that point Nowhere.";
+      type = with lib.types; attrsOf str;
+      default = {};
+    };
+    certs = lib.mkOption {
+      description = "Snakeoil certificate packages.";
+      type = with lib.types; attrsOf package;
+      default = {};
+    };
+  };
+}
diff --git a/modules/motd/default.nix b/modules/motd/default.nix
index be403a6..91417e1 100644
--- a/modules/motd/default.nix
+++ b/modules/motd/default.nix
@@ -1,4 +1,4 @@
-{ config, depot, pkgs, ... }:
+{ cluster, config, depot, pkgs, ... }:
 {
   users.motd = builtins.readFile ./motd.txt;
   environment.interactiveShellInit = let
@@ -8,6 +8,11 @@
     grep = exec pkgs.gnugrep "grep";
     countUsers = '' ${util "who"} -q | ${util "head"} -n1 | ${util "tr"} ' ' \\n | ${util "uniq"} | ${util "wc"} -l'';
     countSessions = '' ${util "who"} -q | ${util "head"} -n1 | ${util "wc"} -w'';
+
+    rev = if cluster.config.simulacrum then
+      "simulacrum"
+    else
+      depot.rev or "\${BRED}(✘)\${CO}\${BWHITE} Dirty";
   in ''
     (
     # Reset colors
@@ -40,7 +45,7 @@
     echo -e " █ ''${BGREEN}(✓)''${CO} ''${BWHITE}You are using a genuine Private Void™ system.''${CO}"
     echo    " █"
     echo -e " █ ''${BWHITE}OS Version....:''${CO} NixOS ''${CAB}${config.system.nixos.version}''${CO}" 
-    echo -e " █ ''${BWHITE}Configuration.:''${CO} ''${CAB}${depot.rev or "\${BRED}(✘)\${CO}\${BWHITE} Dirty"}''${CO}" 
+    echo -e " █ ''${BWHITE}Configuration.:''${CO} ''${CAB}${rev}''${CO}" 
     echo -e " █ ''${BWHITE}Uptime........:''${CO} $(${uptime} -p | ${util "cut"} -d ' ' -f2- | GREP_COLORS='mt=01;35' ${grep} --color=always '[0-9]*')"
     echo -e " █ ''${BWHITE}SSH Logins....:''${CO} There are currently ''${CAB}$(${countUsers})''${CO} users logged in on ''${CAB}$(${countSessions})''${CO} sessions"
     )
diff --git a/packages/catalog/checks.nix b/packages/catalog/checks.nix
index 1dab997..d8c2c72 100644
--- a/packages/catalog/checks.nix
+++ b/packages/catalog/checks.nix
@@ -1,21 +1,32 @@
 { lib, ... }:
 
 {
-  perSystem = { config, ... }: {
-    catalog.depot = {
-      checks = lib.mapAttrs (name: check: {
-        description = "NixOS Test: ${name}";
-        actions = {
-          build = {
-            description = "Build this check.";
-            command = "nix build -L --no-link '${builtins.unsafeDiscardStringContext check.drvPath}^*'";
-          };
-          runInteractive = {
-            description = "Run interactive driver.";
-            command = lib.getExe check.driverInteractive;
-          };
+  perSystem = { config, pkgs, ... }: {
+    catalog = lib.mkMerge (lib.mapAttrsToList (name': check: let
+      simulacrum = lib.hasPrefix "simulacrum-" name';
+      name = lib.removePrefix "simulacrum-" name';
+      baseAttrPath = if simulacrum then
+        [ "cluster" "simulacrum" ]
+      else
+        [ "depot" "checks" ];
+    in lib.setAttrByPath (baseAttrPath ++ [ name ]) {
+      description = if simulacrum then
+        "Simulacrum Test: ${name}"
+      else
+        "NixOS Test: ${name}";
+      actions = {
+        build = {
+          description = "Build this check.";
+          command = "nix build -L --no-link '${builtins.unsafeDiscardStringContext check.drvPath}^*'";
         };
-      }) config.checks;
-    };
+        runInteractive = {
+          description = "Run interactive driver.";
+          command = if simulacrum then
+            "${pkgs.bubblewrap}/bin/bwrap --unshare-all --bind / / --dev-bind /dev /dev ${lib.getExe check.driverInteractive}"
+          else
+            lib.getExe check.driverInteractive;
+        };
+      };
+    }) config.checks);
   };
 }
diff --git a/packages/checks/modules/nixos/external-storage.nix b/packages/checks/modules/nixos/external-storage.nix
new file mode 100644
index 0000000..d89f9df
--- /dev/null
+++ b/packages/checks/modules/nixos/external-storage.nix
@@ -0,0 +1,12 @@
+{ config, lib, ... }:
+
+{
+  systemd.tmpfiles.settings."00-testing-external-storage-underlays" = lib.mapAttrs' (name: cfg: {
+    name = cfg.mountpoint;
+    value.d = {
+      user = toString cfg.uid;
+      group = toString cfg.gid;
+      mode = "0700";
+    };
+  }) config.services.external-storage.underlays;
+}
diff --git a/packages/checks/snakeoil/ssh/snakeoil-key b/packages/checks/snakeoil/ssh/snakeoil-key
new file mode 100644
index 0000000..6faabb2
--- /dev/null
+++ b/packages/checks/snakeoil/ssh/snakeoil-key
@@ -0,0 +1,7 @@
+-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
+QyNTUxOQAAACAOx03X+LtW0aN8ejdN4IJgDPrTZgVwe7WbXhhBvqVwgwAAAJAS78fWEu/H
+1gAAAAtzc2gtZWQyNTUxOQAAACAOx03X+LtW0aN8ejdN4IJgDPrTZgVwe7WbXhhBvqVwgw
+AAAEAUtGOZZIZdzGP6g85JuXBjDtciNQ9bLHNxSN5Gbwvb2Q7HTdf4u1bRo3x6N03ggmAM
++tNmBXB7tZteGEG+pXCDAAAACW1heEBUSVRBTgECAwQ=
+-----END OPENSSH PRIVATE KEY-----
diff --git a/packages/checks/snakeoil/ssh/snakeoil-key.pub b/packages/checks/snakeoil/ssh/snakeoil-key.pub
new file mode 100644
index 0000000..66d752d
--- /dev/null
+++ b/packages/checks/snakeoil/ssh/snakeoil-key.pub
@@ -0,0 +1 @@
+ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIA7HTdf4u1bRo3x6N03ggmAM+tNmBXB7tZteGEG+pXCD