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-rw-r--r--nixos/modules/misc/ids.nix2
-rw-r--r--nixos/modules/programs/bash/bash.nix2
-rw-r--r--nixos/modules/programs/sway-beta.nix33
-rw-r--r--nixos/modules/services/databases/postgresql.nix2
-rw-r--r--nixos/modules/services/mail/rspamd.nix79
-rw-r--r--nixos/modules/services/misc/gitlab.nix221
-rw-r--r--nixos/modules/services/monitoring/prometheus/default.nix29
-rw-r--r--nixos/modules/services/networking/chrony.nix2
-rw-r--r--nixos/modules/services/networking/consul.nix7
-rw-r--r--nixos/modules/services/networking/ntpd.nix2
-rw-r--r--nixos/modules/services/networking/syncthing.nix14
-rw-r--r--nixos/modules/services/search/solr.nix181
-rw-r--r--nixos/modules/services/web-servers/tomcat.nix27
-rw-r--r--nixos/modules/system/activation/activation-script.nix1
-rw-r--r--nixos/modules/virtualisation/amazon-image.nix2
-rw-r--r--nixos/modules/virtualisation/docker-preloader.nix135
-rw-r--r--nixos/modules/virtualisation/google-compute-image.nix1
-rw-r--r--nixos/modules/virtualisation/qemu-vm.nix5
18 files changed, 491 insertions, 254 deletions
diff --git a/nixos/modules/misc/ids.nix b/nixos/modules/misc/ids.nix
index 16737efb1856..6e7f0a007bc2 100644
--- a/nixos/modules/misc/ids.nix
+++ b/nixos/modules/misc/ids.nix
@@ -333,6 +333,7 @@
       lidarr = 306;
       slurm = 307;
       kapacitor = 308;
+      solr = 309;
 
       # When adding a uid, make sure it doesn't match an existing gid. And don't use uids above 399!
 
@@ -626,6 +627,7 @@
       lidarr = 306;
       slurm = 307;
       kapacitor = 308;
+      solr = 309;
 
       # When adding a gid, make sure it doesn't match an existing
       # uid. Users and groups with the same name should have equal
diff --git a/nixos/modules/programs/bash/bash.nix b/nixos/modules/programs/bash/bash.nix
index 0fbc77ea44cf..d325fff6a572 100644
--- a/nixos/modules/programs/bash/bash.nix
+++ b/nixos/modules/programs/bash/bash.nix
@@ -16,7 +16,7 @@ let
     # programmable completion. If we do, enable all modules installed in
     # the system and user profile in obsolete /etc/bash_completion.d/
     # directories. Bash loads completions in all
-    # $XDG_DATA_DIRS/share/bash-completion/completions/
+    # $XDG_DATA_DIRS/bash-completion/completions/
     # on demand, so they do not need to be sourced here.
     if shopt -q progcomp &>/dev/null; then
       . "${pkgs.bash-completion}/etc/profile.d/bash_completion.sh"
diff --git a/nixos/modules/programs/sway-beta.nix b/nixos/modules/programs/sway-beta.nix
index 04f2e0662b86..e651ea4cca33 100644
--- a/nixos/modules/programs/sway-beta.nix
+++ b/nixos/modules/programs/sway-beta.nix
@@ -5,6 +5,15 @@ with lib;
 let
   cfg = config.programs.sway-beta;
   swayPackage = cfg.package;
+
+  swayWrapped = pkgs.writeShellScriptBin "sway" ''
+    ${cfg.extraSessionCommands}
+    exec ${pkgs.dbus.dbus-launch} --exit-with-session ${swayPackage}/bin/sway
+  '';
+  swayJoined = pkgs.symlinkJoin {
+    name = "sway-joined";
+    paths = [ swayWrapped swayPackage ];
+  };
 in {
   options.programs.sway-beta = {
     enable = mkEnableOption ''
@@ -20,13 +29,30 @@ in {
       '';
     };
 
+    extraSessionCommands = mkOption {
+      type = types.lines;
+      default = "";
+      example = ''
+        export SDL_VIDEODRIVER=wayland
+        # needs qt5.qtwayland in systemPackages
+        export QT_QPA_PLATFORM=wayland
+        export QT_WAYLAND_DISABLE_WINDOWDECORATION="1"
+        # Fix for some Java AWT applications (e.g. Android Studio),
+        # use this if they aren't displayed properly:
+        export _JAVA_AWT_WM_NONREPARENTING=1
+      '';
+      description = ''
+        Shell commands executed just before Sway is started.
+      '';
+    };
+
     extraPackages = mkOption {
       type = with types; listOf package;
       default = with pkgs; [
-        xwayland dmenu
+        xwayland rxvt_unicode dmenu
       ];
       defaultText = literalExample ''
-        with pkgs; [ xwayland dmenu ];
+        with pkgs; [ xwayland rxvt_unicode dmenu ];
       '';
       example = literalExample ''
         with pkgs; [
@@ -42,7 +68,7 @@ in {
   };
 
   config = mkIf cfg.enable {
-    environment.systemPackages = [ swayPackage ] ++ cfg.extraPackages;
+    environment.systemPackages = [ swayJoined ] ++ cfg.extraPackages;
     security.pam.services.swaylock = {};
     hardware.opengl.enable = mkDefault true;
     fonts.enableDefaultFonts = mkDefault true;
@@ -51,4 +77,3 @@ in {
 
   meta.maintainers = with lib.maintainers; [ gnidorah primeos colemickens ];
 }
-
diff --git a/nixos/modules/services/databases/postgresql.nix b/nixos/modules/services/databases/postgresql.nix
index 6edb1503c233..f592be0e768b 100644
--- a/nixos/modules/services/databases/postgresql.nix
+++ b/nixos/modules/services/databases/postgresql.nix
@@ -271,5 +271,5 @@ in
   };
 
   meta.doc = ./postgresql.xml;
-
+  meta.maintainers = with lib.maintainers; [ thoughtpolice ];
 }
diff --git a/nixos/modules/services/mail/rspamd.nix b/nixos/modules/services/mail/rspamd.nix
index ff01a5dee53d..d83d6f1f750c 100644
--- a/nixos/modules/services/mail/rspamd.nix
+++ b/nixos/modules/services/mail/rspamd.nix
@@ -127,11 +127,15 @@ let
       options {
         pidfile = "$RUNDIR/rspamd.pid";
         .include "$CONFDIR/options.inc"
+        .include(try=true; priority=1,duplicate=merge) "$LOCAL_CONFDIR/local.d/options.inc"
+        .include(try=true; priority=10) "$LOCAL_CONFDIR/override.d/options.inc"
       }
 
       logging {
         type = "syslog";
         .include "$CONFDIR/logging.inc"
+        .include(try=true; priority=1,duplicate=merge) "$LOCAL_CONFDIR/local.d/logging.inc"
+        .include(try=true; priority=10) "$LOCAL_CONFDIR/override.d/logging.inc"
       }
 
       ${concatStringsSep "\n" (mapAttrsToList (name: value: ''
@@ -149,6 +153,41 @@ let
       ${cfg.extraConfig}
    '';
 
+  rspamdDir = pkgs.linkFarm "etc-rspamd-dir" (
+    (mapAttrsToList (name: file: { name = "local.d/${name}"; path = file.source; }) cfg.locals) ++
+    (mapAttrsToList (name: file: { name = "override.d/${name}"; path = file.source; }) cfg.overrides) ++
+    (optional (cfg.localLuaRules != null) { name = "rspamd.local.lua"; path = cfg.localLuaRules; }) ++
+    [ { name = "rspamd.conf"; path = rspamdConfFile; } ]
+  );
+
+  configFileModule = prefix: { name, config, ... }: {
+    options = {
+      enable = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Whether this file ${prefix} should be generated.  This
+          option allows specific ${prefix} files to be disabled.
+        '';
+      };
+
+      text = mkOption {
+        default = null;
+        type = types.nullOr types.lines;
+        description = "Text of the file.";
+      };
+
+      source = mkOption {
+        type = types.path;
+        description = "Path of the source file.";
+      };
+    };
+    config = {
+      source = mkIf (config.text != null) (
+        let name' = "rspamd-${prefix}-" + baseNameOf name;
+        in mkDefault (pkgs.writeText name' config.text));
+    };
+  };
 in
 
 {
@@ -167,6 +206,41 @@ in
         description = "Whether to run the rspamd daemon in debug mode.";
       };
 
+      locals = mkOption {
+        type = with types; loaOf (submodule (configFileModule "locals"));
+        default = {};
+        description = ''
+          Local configuration files, written into <filename>/etc/rspamd/local.d/{name}</filename>.
+        '';
+        example = literalExample ''
+          { "redis.conf".source = "/nix/store/.../etc/dir/redis.conf";
+            "arc.conf".text = "allow_envfrom_empty = true;";
+          }
+        '';
+      };
+
+      overrides = mkOption {
+        type = with types; loaOf (submodule (configFileModule "overrides"));
+        default = {};
+        description = ''
+          Overridden configuration files, written into <filename>/etc/rspamd/override.d/{name}</filename>.
+        '';
+        example = literalExample ''
+          { "redis.conf".source = "/nix/store/.../etc/dir/redis.conf";
+            "arc.conf".text = "allow_envfrom_empty = true;";
+          }
+        '';
+      };
+
+      localLuaRules = mkOption {
+        default = null;
+        type = types.nullOr types.path;
+        description = ''
+          Path of file to link to <filename>/etc/rspamd/rspamd.local.lua</filename> for local
+          rules written in Lua
+        '';
+      };
+
       workers = mkOption {
         type = with types; attrsOf (submodule workerOpts);
         description = ''
@@ -242,16 +316,17 @@ in
       gid = config.ids.gids.rspamd;
     };
 
-    environment.etc."rspamd.conf".source = rspamdConfFile;
+    environment.etc."rspamd".source = rspamdDir;
 
     systemd.services.rspamd = {
       description = "Rspamd Service";
 
       wantedBy = [ "multi-user.target" ];
       after = [ "network.target" ];
+      restartTriggers = [ rspamdDir ];
 
       serviceConfig = {
-        ExecStart = "${pkgs.rspamd}/bin/rspamd ${optionalString cfg.debug "-d"} --user=${cfg.user} --group=${cfg.group} --pid=/run/rspamd.pid -c ${rspamdConfFile} -f";
+        ExecStart = "${pkgs.rspamd}/bin/rspamd ${optionalString cfg.debug "-d"} --user=${cfg.user} --group=${cfg.group} --pid=/run/rspamd.pid -c /etc/rspamd/rspamd.conf -f";
         Restart = "always";
         RuntimeDirectory = "rspamd";
         PrivateTmp = true;
diff --git a/nixos/modules/services/misc/gitlab.nix b/nixos/modules/services/misc/gitlab.nix
index 8ea831afb7c1..aa72cda70453 100644
--- a/nixos/modules/services/misc/gitlab.nix
+++ b/nixos/modules/services/misc/gitlab.nix
@@ -14,15 +14,16 @@ let
   pathUrlQuote = url: replaceStrings ["/"] ["%2F"] url;
   pgSuperUser = config.services.postgresql.superUser;
 
-  databaseYml = ''
-    production:
-      adapter: postgresql
-      database: ${cfg.databaseName}
-      host: ${cfg.databaseHost}
-      password: ${cfg.databasePassword}
-      username: ${cfg.databaseUsername}
-      encoding: utf8
-  '';
+  databaseConfig = {
+    production = {
+      adapter = "postgresql";
+      database = cfg.databaseName;
+      host = cfg.databaseHost;
+      password = cfg.databasePassword;
+      username = cfg.databaseUsername;
+      encoding = "utf8";
+    };
+  };
 
   gitalyToml = pkgs.writeText "gitaly.toml" ''
     socket_path = "${lib.escape ["\""] gitalySocket}"
@@ -45,35 +46,31 @@ let
     '') gitlabConfig.production.repositories.storages))}
   '';
 
-  gitlabShellYml = ''
-    user: ${cfg.user}
-    gitlab_url: "http+unix://${pathUrlQuote gitlabSocket}"
-    http_settings:
-      self_signed_cert: false
-    repos_path: "${cfg.statePath}/repositories"
-    secret_file: "${cfg.statePath}/config/gitlab_shell_secret"
-    log_file: "${cfg.statePath}/log/gitlab-shell.log"
-    custom_hooks_dir: "${cfg.statePath}/custom_hooks"
-    redis:
-      bin: ${pkgs.redis}/bin/redis-cli
-      host: 127.0.0.1
-      port: 6379
-      database: 0
-      namespace: resque:gitlab
-  '';
+  gitlabShellConfig = {
+    user = cfg.user;
+    gitlab_url = "http+unix://${pathUrlQuote gitlabSocket}";
+    http_settings.self_signed_cert = false;
+    repos_path = "${cfg.statePath}/repositories";
+    secret_file = "${cfg.statePath}/config/gitlab_shell_secret";
+    log_file = "${cfg.statePath}/log/gitlab-shell.log";
+    custom_hooks_dir = "${cfg.statePath}/custom_hooks";
+    redis = {
+      bin = "${pkgs.redis}/bin/redis-cli";
+      host = "127.0.0.1";
+      port = 6379;
+      database = 0;
+      namespace = "resque:gitlab";
+    };
+  };
 
-  redisYml = ''
-    production:
-      url: redis://localhost:6379/
-  '';
+  redisConfig.production.url = "redis://localhost:6379/";
 
-  secretsYml = ''
-    production:
-      secret_key_base: ${cfg.secrets.secret}
-      otp_key_base: ${cfg.secrets.otp}
-      db_key_base: ${cfg.secrets.db}
-      openid_connect_signing_key: ${builtins.toJSON cfg.secrets.jws}
-  '';
+  secretsConfig.production = {
+    secret_key_base = cfg.secrets.secret;
+    otp_key_base = cfg.secrets.otp;
+    db_key_base = cfg.secrets.db;
+    openid_connect_signing_key = cfg.secrets.jws;
+  };
 
   gitlabConfig = {
     # These are the default settings from config/gitlab.example.yml
@@ -115,12 +112,8 @@ let
         upload_pack = true;
         receive_pack = true;
       };
-      workhorse = {
-        secret_file = "${cfg.statePath}/.gitlab_workhorse_secret";
-      };
-      git = {
-        bin_path = "git";
-      };
+      workhorse.secret_file = "${cfg.statePath}/.gitlab_workhorse_secret";
+      git.bin_path = "git";
       monitoring = {
         ip_whitelist = [ "127.0.0.0/8" "::1/128" ];
         sidekiq_exporter = {
@@ -138,7 +131,7 @@ let
     HOME = "${cfg.statePath}/home";
     UNICORN_PATH = "${cfg.statePath}/";
     GITLAB_PATH = "${cfg.packages.gitlab}/share/gitlab/";
-    GITLAB_STATE_PATH = "${cfg.statePath}";
+    GITLAB_STATE_PATH = cfg.statePath;
     GITLAB_UPLOADS_PATH = "${cfg.statePath}/uploads";
     SCHEMA = "${cfg.statePath}/db/schema.rb";
     GITLAB_LOG_PATH = "${cfg.statePath}/log";
@@ -146,13 +139,11 @@ let
     GITLAB_SHELL_CONFIG_PATH = "${cfg.statePath}/shell/config.yml";
     GITLAB_SHELL_SECRET_PATH = "${cfg.statePath}/config/gitlab_shell_secret";
     GITLAB_SHELL_HOOKS_PATH = "${cfg.statePath}/shell/hooks";
-    GITLAB_REDIS_CONFIG_FILE = pkgs.writeText "gitlab-redis.yml" redisYml;
+    GITLAB_REDIS_CONFIG_FILE = pkgs.writeText "redis.yml" (builtins.toJSON redisConfig);
     prometheus_multiproc_dir = "/run/gitlab";
     RAILS_ENV = "production";
   };
 
-  unicornConfig = builtins.readFile ./defaultUnicornConfig.rb;
-
   gitlab-rake = pkgs.stdenv.mkDerivation rec {
     name = "gitlab-rake";
     buildInputs = [ pkgs.makeWrapper ];
@@ -162,7 +153,6 @@ let
       mkdir -p $out/bin
       makeWrapper ${cfg.packages.gitlab.rubyEnv}/bin/rake $out/bin/gitlab-rake \
           ${concatStrings (mapAttrsToList (name: value: "--set ${name} '${value}' ") gitlabEnv)} \
-          --set GITLAB_CONFIG_PATH '${cfg.statePath}/config' \
           --set PATH '${lib.makeBinPath [ pkgs.nodejs pkgs.gzip pkgs.git pkgs.gnutar config.services.postgresql.package pkgs.coreutils pkgs.procps ]}:$PATH' \
           --set RAKEOPT '-f ${cfg.packages.gitlab}/share/gitlab/Rakefile' \
           --run 'cd ${cfg.packages.gitlab}/share/gitlab'
@@ -306,7 +296,6 @@ in {
 
       initialRootPassword = mkOption {
         type = types.str;
-        default = "UseNixOS!";
         description = ''
           Initial password of the root account if this is a new install.
         '';
@@ -461,10 +450,30 @@ in {
       }
     ];
 
+    systemd.tmpfiles.rules = [
+      "d /run/gitlab 0755 ${cfg.user} ${cfg.group} -"
+      "d ${gitlabEnv.HOME} 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.backupPath} 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/builds 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/config 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/db 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/log 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/repositories 2770 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/shell 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/tmp/pids 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/tmp/sockets 0750 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/uploads 0700 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/custom_hooks/pre-receive.d 0700 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/custom_hooks/post-receive.d 0700 ${cfg.user} ${cfg.group} -"
+      "d ${cfg.statePath}/custom_hooks/update.d 0700 ${cfg.user} ${cfg.group} -"
+      "d ${gitlabConfig.production.shared.path}/artifacts 0750 ${cfg.user} ${cfg.group} -"
+      "d ${gitlabConfig.production.shared.path}/lfs-objects 0750 ${cfg.user} ${cfg.group} -"
+      "d ${gitlabConfig.production.shared.path}/pages 0750 ${cfg.user} ${cfg.group} -"
+    ];
+
     systemd.services.gitlab-sidekiq = {
-      after = [ "network.target" "redis.service" ];
+      after = [ "network.target" "redis.service" "gitlab.service" ];
       wantedBy = [ "multi-user.target" ];
-      partOf = [ "gitlab.service" ];
       environment = gitlabEnv;
       path = with pkgs; [
         config.services.postgresql.package
@@ -486,10 +495,8 @@ in {
     };
 
     systemd.services.gitaly = {
-      after = [ "network.target" "gitlab.service" ];
+      after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
-      environment.HOME = gitlabEnv.HOME;
-      environment.GITLAB_SHELL_CONFIG_PATH = gitlabEnv.GITLAB_SHELL_CONFIG_PATH;
       path = with pkgs; [ gitAndTools.git cfg.packages.gitaly.rubyEnv cfg.packages.gitaly.rubyEnv.wrappedRuby ];
       serviceConfig = {
         Type = "simple";
@@ -505,8 +512,6 @@ in {
     systemd.services.gitlab-workhorse = {
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
-      environment.HOME = gitlabEnv.HOME;
-      environment.GITLAB_SHELL_CONFIG_PATH = gitlabEnv.GITLAB_SHELL_CONFIG_PATH;
       path = with pkgs; [
         gitAndTools.git
         gnutar
@@ -514,10 +519,6 @@ in {
         openssh
         gitlab-workhorse
       ];
-      preStart = ''
-        mkdir -p /run/gitlab
-        chown ${cfg.user}:${cfg.group} /run/gitlab
-      '';
       serviceConfig = {
         PermissionsStartOnly = true; # preStart must be run as root
         Type = "simple";
@@ -538,7 +539,7 @@ in {
     };
 
     systemd.services.gitlab = {
-      after = [ "network.target" "postgresql.service" "redis.service" ];
+      after = [ "gitlab-workhorse.service" "gitaly.service" "network.target" "postgresql.service" "redis.service" ];
       requires = [ "gitlab-sidekiq.service" ];
       wantedBy = [ "multi-user.target" ];
       environment = gitlabEnv;
@@ -551,102 +552,76 @@ in {
         gnupg
       ];
       preStart = ''
-        mkdir -p ${cfg.backupPath}
-        mkdir -p ${cfg.statePath}/builds
-        mkdir -p ${cfg.statePath}/repositories
-        mkdir -p ${gitlabConfig.production.shared.path}/artifacts
-        mkdir -p ${gitlabConfig.production.shared.path}/lfs-objects
-        mkdir -p ${gitlabConfig.production.shared.path}/pages
-        mkdir -p ${cfg.statePath}/log
-        mkdir -p ${cfg.statePath}/tmp/pids
-        mkdir -p ${cfg.statePath}/tmp/sockets
-        mkdir -p ${cfg.statePath}/shell
-        mkdir -p ${cfg.statePath}/db
-        mkdir -p ${cfg.statePath}/uploads
-        mkdir -p ${cfg.statePath}/custom_hooks/pre-receive.d
-        mkdir -p ${cfg.statePath}/custom_hooks/post-receive.d
-        mkdir -p ${cfg.statePath}/custom_hooks/update.d
-
-        rm -rf ${cfg.statePath}/config ${cfg.statePath}/shell/hooks
-        mkdir -p ${cfg.statePath}/config
-
-        ${pkgs.openssl}/bin/openssl rand -hex 32 > ${cfg.statePath}/config/gitlab_shell_secret
-
-        mkdir -p /run/gitlab
-        mkdir -p ${cfg.statePath}/log
-        [ -d /run/gitlab/log ] || ln -sf ${cfg.statePath}/log /run/gitlab/log
-        [ -d /run/gitlab/tmp ] || ln -sf ${cfg.statePath}/tmp /run/gitlab/tmp
-        [ -d /run/gitlab/uploads ] || ln -sf ${cfg.statePath}/uploads /run/gitlab/uploads
-        ln -sf $GITLAB_SHELL_CONFIG_PATH /run/gitlab/shell-config.yml
-        chown -R ${cfg.user}:${cfg.group} /run/gitlab
-
-        # Prepare home directory
-        mkdir -p ${gitlabEnv.HOME}/.ssh
-        touch ${gitlabEnv.HOME}/.ssh/authorized_keys
-        chown -R ${cfg.user}:${cfg.group} ${gitlabEnv.HOME}/
-
         cp -rf ${cfg.packages.gitlab}/share/gitlab/db/* ${cfg.statePath}/db
-        cp -rf ${cfg.packages.gitlab}/share/gitlab/config.dist/* ${cfg.statePath}/config
-        ${optionalString cfg.smtp.enable ''
-          ln -sf ${smtpSettings} ${cfg.statePath}/config/initializers/smtp_settings.rb
-        ''}
-        ln -sf ${cfg.statePath}/config /run/gitlab/config
+        rm -rf ${cfg.statePath}/config
+        mkdir ${cfg.statePath}/config
         if [ -e ${cfg.statePath}/lib ]; then
           rm ${cfg.statePath}/lib
         fi
-        ln -sf ${pkgs.gitlab}/share/gitlab/lib ${cfg.statePath}/lib
+
+        ln -sf ${cfg.packages.gitlab}/share/gitlab/lib ${cfg.statePath}/lib
+        [ -L /run/gitlab/config ] || ln -sf ${cfg.statePath}/config /run/gitlab/config
+        [ -L /run/gitlab/log ] || ln -sf ${cfg.statePath}/log /run/gitlab/log
+        [ -L /run/gitlab/tmp ] || ln -sf ${cfg.statePath}/tmp /run/gitlab/tmp
+        [ -L /run/gitlab/uploads ] || ln -sf ${cfg.statePath}/uploads /run/gitlab/uploads
+        ${optionalString cfg.smtp.enable ''
+          ln -sf ${smtpSettings} ${cfg.statePath}/config/initializers/smtp_settings.rb
+        ''}
         cp ${cfg.packages.gitlab}/share/gitlab/VERSION ${cfg.statePath}/VERSION
+        cp -rf ${cfg.packages.gitlab}/share/gitlab/config.dist/* ${cfg.statePath}/config
+        ${pkgs.openssl}/bin/openssl rand -hex 32 > ${cfg.statePath}/config/gitlab_shell_secret
 
         # JSON is a subset of YAML
-        ln -fs ${pkgs.writeText "gitlab.yml" (builtins.toJSON gitlabConfig)} ${cfg.statePath}/config/gitlab.yml
-        ln -fs ${pkgs.writeText "database.yml" databaseYml} ${cfg.statePath}/config/database.yml
-        ln -fs ${pkgs.writeText "secrets.yml" secretsYml} ${cfg.statePath}/config/secrets.yml
-        ln -fs ${pkgs.writeText "unicorn.rb" unicornConfig} ${cfg.statePath}/config/unicorn.rb
-
-        chown -R ${cfg.user}:${cfg.group} ${cfg.statePath}/
-        chmod -R ug+rwX,o-rwx+X ${cfg.statePath}/
+        ln -sf ${pkgs.writeText "gitlab.yml" (builtins.toJSON gitlabConfig)} ${cfg.statePath}/config/gitlab.yml
+        ln -sf ${pkgs.writeText "database.yml" (builtins.toJSON databaseConfig)} ${cfg.statePath}/config/database.yml
+        ln -sf ${pkgs.writeText "secrets.yml" (builtins.toJSON secretsConfig)} ${cfg.statePath}/config/secrets.yml
+        ln -sf ${./defaultUnicornConfig.rb} ${cfg.statePath}/config/unicorn.rb
 
         # Install the shell required to push repositories
-        ln -fs ${pkgs.writeText "config.yml" gitlabShellYml} "$GITLAB_SHELL_CONFIG_PATH"
-        ln -fs ${cfg.packages.gitlab-shell}/hooks "$GITLAB_SHELL_HOOKS_PATH"
+        ln -sf ${pkgs.writeText "config.yml" (builtins.toJSON gitlabShellConfig)} /run/gitlab/shell-config.yml
+        [ -L ${cfg.statePath}/shell/hooks ] ||  ln -sf ${cfg.packages.gitlab-shell}/hooks ${cfg.statePath}/shell/hooks
         ${cfg.packages.gitlab-shell}/bin/install
 
-        if [ "${cfg.databaseHost}" = "127.0.0.1" ]; then
-          if ! test -e "${cfg.statePath}/db-created"; then
+        chown -R ${cfg.user}:${cfg.group} ${cfg.statePath}/
+        chmod -R ug+rwX,o-rwx+X ${cfg.statePath}/
+        chown -R ${cfg.user}:${cfg.group} /run/gitlab
+
+        if ! test -e "${cfg.statePath}/db-created"; then
+          if [ "${cfg.databaseHost}" = "127.0.0.1" ]; then
             ${pkgs.sudo}/bin/sudo -u ${pgSuperUser} psql postgres -c "CREATE ROLE ${cfg.databaseUsername} WITH LOGIN NOCREATEDB NOCREATEROLE ENCRYPTED PASSWORD '${cfg.databasePassword}'"
             ${pkgs.sudo}/bin/sudo -u ${pgSuperUser} ${config.services.postgresql.package}/bin/createdb --owner ${cfg.databaseUsername} ${cfg.databaseName}
-            touch "${cfg.statePath}/db-created"
+
+            # enable required pg_trgm extension for gitlab
+            ${pkgs.sudo}/bin/sudo -u ${pgSuperUser} psql ${cfg.databaseName} -c "CREATE EXTENSION IF NOT EXISTS pg_trgm"
           fi
 
-          # enable required pg_trgm extension for gitlab
-          ${pkgs.sudo}/bin/sudo -u ${pgSuperUser} psql ${cfg.databaseName} -c "CREATE EXTENSION IF NOT EXISTS pg_trgm"
+          ${pkgs.sudo}/bin/sudo -u ${cfg.user} -H ${gitlab-rake}/bin/gitlab-rake db:schema:load
+
+          touch "${cfg.statePath}/db-created"
         fi
 
         # Always do the db migrations just to be sure the database is up-to-date
-        ${gitlab-rake}/bin/gitlab-rake db:migrate RAILS_ENV=production
+        ${pkgs.sudo}/bin/sudo -u ${cfg.user} -H ${gitlab-rake}/bin/gitlab-rake db:migrate
 
-        # The gitlab:setup task is horribly broken somehow, the db:migrate
-        # task above and the db:seed_fu below will do the same for setting
-        # up the initial database
         if ! test -e "${cfg.statePath}/db-seeded"; then
-          ${gitlab-rake}/bin/gitlab-rake db:seed_fu RAILS_ENV=production \
+          ${pkgs.sudo}/bin/sudo -u ${cfg.user} ${gitlab-rake}/bin/gitlab-rake db:seed_fu \
             GITLAB_ROOT_PASSWORD='${cfg.initialRootPassword}' GITLAB_ROOT_EMAIL='${cfg.initialRootEmail}'
           touch "${cfg.statePath}/db-seeded"
         fi
 
         # The gitlab:shell:setup regenerates the authorized_keys file so that
         # the store path to the gitlab-shell in it gets updated
-        ${pkgs.sudo}/bin/sudo -u ${cfg.user} force=yes ${gitlab-rake}/bin/gitlab-rake gitlab:shell:setup RAILS_ENV=production
+        ${pkgs.sudo}/bin/sudo -u ${cfg.user} -H force=yes ${gitlab-rake}/bin/gitlab-rake gitlab:shell:setup
 
         # The gitlab:shell:create_hooks task seems broken for fixing links
         # so we instead delete all the hooks and create them anew
         rm -f ${cfg.statePath}/repositories/**/*.git/hooks
-        ${gitlab-rake}/bin/gitlab-rake gitlab:shell:create_hooks RAILS_ENV=production
+        ${pkgs.sudo}/bin/sudo -u ${cfg.user} -H ${gitlab-rake}/bin/gitlab-rake gitlab:shell:create_hooks
+
+        ${pkgs.sudo}/bin/sudo -u ${cfg.user} -H ${pkgs.git}/bin/git config --global core.autocrlf "input"
 
         # Change permissions in the last step because some of the
         # intermediary scripts like to create directories as root.
-        chown -R ${cfg.user}:${cfg.group} ${cfg.statePath}
-        chmod -R ug+rwX,o-rwx+X ${cfg.statePath}
         chmod -R u+rwX,go-rwx+X ${gitlabEnv.HOME}
         chmod -R ug+rwX,o-rwx ${cfg.statePath}/repositories
         chmod -R ug-s ${cfg.statePath}/repositories
diff --git a/nixos/modules/services/monitoring/prometheus/default.nix b/nixos/modules/services/monitoring/prometheus/default.nix
index e2ee995cea80..bf4dfc666bb6 100644
--- a/nixos/modules/services/monitoring/prometheus/default.nix
+++ b/nixos/modules/services/monitoring/prometheus/default.nix
@@ -10,6 +10,13 @@ let
   # Get a submodule without any embedded metadata:
   _filter = x: filterAttrs (k: v: k != "_module") x;
 
+  # a wrapper that verifies that the configuration is valid
+  promtoolCheck = what: name: file: pkgs.runCommand "${name}-${what}-checked"
+    { buildInputs = [ cfg.package ]; } ''
+    ln -s ${file} $out
+    promtool ${what} $out
+  '';
+
   # Pretty-print JSON to a file
   writePrettyJSON = name: x:
     pkgs.runCommand name { } ''
@@ -19,18 +26,19 @@ let
   # This becomes the main config file
   promConfig = {
     global = cfg.globalConfig;
-    rule_files = cfg.ruleFiles ++ [
+    rule_files = map (promtoolCheck "check-rules" "rules") (cfg.ruleFiles ++ [
       (pkgs.writeText "prometheus.rules" (concatStringsSep "\n" cfg.rules))
-    ];
+    ]);
     scrape_configs = cfg.scrapeConfigs;
   };
 
   generatedPrometheusYml = writePrettyJSON "prometheus.yml" promConfig;
 
-  prometheusYml =
-    if cfg.configText != null then
+  prometheusYml = let
+    yml =  if cfg.configText != null then
       pkgs.writeText "prometheus.yml" cfg.configText
-    else generatedPrometheusYml;
+      else generatedPrometheusYml;
+    in promtoolCheck "check-config" "prometheus.yml" yml;
 
   cmdlineArgs = cfg.extraFlags ++ [
     "-storage.local.path=${cfg.dataDir}/metrics"
@@ -376,6 +384,15 @@ in {
         '';
       };
 
+      package = mkOption {
+        type = types.package;
+        default = pkgs.prometheus;
+        defaultText = "pkgs.prometheus";
+        description = ''
+          The prometheus package that should be used.
+        '';
+      };
+
       listenAddress = mkOption {
         type = types.str;
         default = "0.0.0.0:9090";
@@ -495,7 +512,7 @@ in {
       after    = [ "network.target" ];
       script = ''
         #!/bin/sh
-        exec ${pkgs.prometheus}/bin/prometheus \
+        exec ${cfg.package}/bin/prometheus \
           ${concatStringsSep " \\\n  " cmdlineArgs}
       '';
       serviceConfig = {
diff --git a/nixos/modules/services/networking/chrony.nix b/nixos/modules/services/networking/chrony.nix
index a363b545d649..9b8005e706ae 100644
--- a/nixos/modules/services/networking/chrony.nix
+++ b/nixos/modules/services/networking/chrony.nix
@@ -93,6 +93,8 @@ in
 
     services.timesyncd.enable = mkForce false;
 
+    systemd.services.systemd-timedated.environment = { SYSTEMD_TIMEDATED_NTP_SERVICES = "chronyd.service"; };
+
     systemd.services.chronyd =
       { description = "chrony NTP daemon";
 
diff --git a/nixos/modules/services/networking/consul.nix b/nixos/modules/services/networking/consul.nix
index ab3f81037681..0e90fed788b9 100644
--- a/nixos/modules/services/networking/consul.nix
+++ b/nixos/modules/services/networking/consul.nix
@@ -6,9 +6,10 @@ let
   dataDir = "/var/lib/consul";
   cfg = config.services.consul;
 
-  configOptions = { data_dir = dataDir; } //
-    (if cfg.webUi then { ui_dir = "${cfg.package.ui}"; } else { }) //
-    cfg.extraConfig;
+  configOptions = {
+    data_dir = dataDir;
+    ui = cfg.webUi;
+  } // cfg.extraConfig;
 
   configFiles = [ "/etc/consul.json" "/etc/consul-addrs.json" ]
     ++ cfg.extraConfigFiles;
diff --git a/nixos/modules/services/networking/ntpd.nix b/nixos/modules/services/networking/ntpd.nix
index 342350d49ab3..32174100b0f7 100644
--- a/nixos/modules/services/networking/ntpd.nix
+++ b/nixos/modules/services/networking/ntpd.nix
@@ -67,6 +67,8 @@ in
     environment.systemPackages = [ pkgs.ntp ];
     services.timesyncd.enable = mkForce false;
 
+    systemd.services.systemd-timedated.environment = { SYSTEMD_TIMEDATED_NTP_SERVICES = "ntpd.service"; };
+
     users.users = singleton
       { name = ntpUser;
         uid = config.ids.uids.ntp;
diff --git a/nixos/modules/services/networking/syncthing.nix b/nixos/modules/services/networking/syncthing.nix
index fd31b2a67687..b2ef1885a955 100644
--- a/nixos/modules/services/networking/syncthing.nix
+++ b/nixos/modules/services/networking/syncthing.nix
@@ -63,8 +63,20 @@ in {
         type = types.path;
         default = "/var/lib/syncthing";
         description = ''
+          Path where synced directories will exist.
+        '';
+      };
+
+      configDir = mkOption {
+        type = types.path;
+        description = ''
           Path where the settings and keys will exist.
         '';
+        default =
+          let
+            nixos = config.system.stateVersion;
+            cond  = versionAtLeast nixos "19.03";
+          in cfg.dataDir + (optionalString cond "/.config/syncthing");
       };
 
       openDefaultPorts = mkOption {
@@ -144,7 +156,7 @@ in {
             ${cfg.package}/bin/syncthing \
               -no-browser \
               -gui-address=${cfg.guiAddress} \
-              -home=${cfg.dataDir}
+              -home=${cfg.configDir}
           '';
         };
       };
diff --git a/nixos/modules/services/search/solr.nix b/nixos/modules/services/search/solr.nix
index 90140a337ed8..7200c40e89f7 100644
--- a/nixos/modules/services/search/solr.nix
+++ b/nixos/modules/services/search/solr.nix
@@ -6,142 +6,105 @@ let
 
   cfg = config.services.solr;
 
-  # Assemble all jars needed for solr
-  solrJars = pkgs.stdenv.mkDerivation {
-    name = "solr-jars";
-
-    src = pkgs.fetchurl {
-      url = http://archive.apache.org/dist/tomcat/tomcat-5/v5.5.36/bin/apache-tomcat-5.5.36.tar.gz;
-      sha256 = "01mzvh53wrs1p2ym765jwd00gl6kn8f9k3nhdrnhdqr8dhimfb2p";
-    };
-
-    installPhase = ''
-      mkdir -p $out/lib
-      cp common/lib/*.jar $out/lib/
-      ln -s ${pkgs.ant}/lib/ant/lib/ant.jar $out/lib/
-      ln -s ${cfg.solrPackage}/lib/ext/* $out/lib/
-      ln -s ${pkgs.jdk.home}/lib/tools.jar $out/lib/
-    '' + optionalString (cfg.extraJars != []) ''
-      for f in ${concatStringsSep " " cfg.extraJars}; do
-         cp $f $out/lib
-      done
-    '';
-  };
-
-in {
+in
 
+{
   options = {
     services.solr = {
-      enable = mkOption {
-        type = types.bool;
-        default = false;
-        description = ''
-          Enables the solr service.
-        '';
-      };
-
-      javaPackage = mkOption {
-        type = types.package;
-        default = pkgs.jre;
-        defaultText = "pkgs.jre";
-        description = ''
-          Which Java derivation to use for running solr.
-        '';
-      };
+      enable = mkEnableOption "Enables the solr service.";
 
-      solrPackage = mkOption {
+      package = mkOption {
         type = types.package;
         default = pkgs.solr;
         defaultText = "pkgs.solr";
-        description = ''
-          Which solr derivation to use for running solr.
-        '';
+        description = "Which Solr package to use.";
       };
 
-      extraJars = mkOption {
-        type = types.listOf types.path;
-        default = [];
-        description = ''
-          List of paths pointing to jars. Jars are copied to commonLibFolder to be available to java/solr.
-        '';
+      port = mkOption {
+        type = types.int;
+        default = 8983;
+        description = "Port on which Solr is ran.";
       };
 
-      log4jConfiguration = mkOption {
-        type = types.lines;
-        default = ''
-          log4j.rootLogger=INFO, stdout
-          log4j.appender.stdout=org.apache.log4j.ConsoleAppender
-          log4j.appender.stdout.Target=System.out
-          log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
-          log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
-        '';
-        description = ''
-          Contents of the <literal>log4j.properties</literal> used. By default,
-          everything is logged to stdout (picked up by systemd) with level INFO.
-        '';
+      stateDir = mkOption {
+        type = types.path;
+        default = "/var/lib/solr";
+        description = "The solr home directory containing config, data, and logging files.";
       };
 
-      user = mkOption {
-        type = types.str;
-        description = ''
-          The user that should run the solr process and.
-          the working directories.
-        '';
+      extraJavaOptions = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = "Extra command line options given to the java process running Solr.";
       };
 
-      group = mkOption {
+      user = mkOption {
         type = types.str;
-        description = ''
-          The group that will own the working directory.
-        '';
+        default = "solr";
+        description = "User under which Solr is ran.";
       };
 
-      solrHome = mkOption {
+      group = mkOption {
         type = types.str;
-        description = ''
-          The solr home directory. It is your own responsibility to
-          make sure this directory contains a working solr configuration,
-          and is writeable by the the user running the solr service.
-          Failing to do so, the solr will not start properly.
-        '';
-      };
-
-      extraJavaOptions = mkOption {
-        type = types.listOf types.str;
-        default = [];
-        description = ''
-          Extra command line options given to the java process running
-          solr.
-        '';
-      };
-
-      extraWinstoneOptions = mkOption {
-        type = types.listOf types.str;
-        default = [];
-        description = ''
-          Extra command line options given to the Winstone, which is
-          the servlet container hosting solr.
-        '';
+        default = "solr";
+        description = "Group under which Solr is ran.";
       };
     };
   };
 
   config = mkIf cfg.enable {
 
-    services.winstone.solr = {
-      serviceName = "solr";
-      inherit (cfg) user group javaPackage;
-      warFile = "${cfg.solrPackage}/lib/solr.war";
-      extraOptions = [
-        "--commonLibFolder=${solrJars}/lib"
-        "--useJasper"
-      ] ++ cfg.extraWinstoneOptions;
-      extraJavaOptions = [
-        "-Dsolr.solr.home=${cfg.solrHome}"
-        "-Dlog4j.configuration=file://${pkgs.writeText "log4j.properties" cfg.log4jConfiguration}"
-      ] ++ cfg.extraJavaOptions;
+    environment.systemPackages = [ cfg.package ];
+
+    systemd.services.solr = {
+      after = [ "network.target" "remote-fs.target" "nss-lookup.target" "systemd-journald-dev-log.socket" ];
+      wantedBy = [ "multi-user.target" ];
+
+      environment = {
+        SOLR_HOME = "${cfg.stateDir}/data";
+        LOG4J_PROPS = "${cfg.stateDir}/log4j2.xml";
+        SOLR_LOGS_DIR = "${cfg.stateDir}/logs";
+        SOLR_PORT = "${toString cfg.port}";
+      };
+      path = with pkgs; [
+        gawk
+        procps
+      ];
+      preStart = ''
+        mkdir -p "${cfg.stateDir}/data";
+        mkdir -p "${cfg.stateDir}/logs";
+
+        if ! test -e "${cfg.stateDir}/data/solr.xml"; then
+          install -D -m0640 ${cfg.package}/server/solr/solr.xml "${cfg.stateDir}/data/solr.xml"
+          install -D -m0640 ${cfg.package}/server/solr/zoo.cfg "${cfg.stateDir}/data/zoo.cfg"
+        fi
+
+        if ! test -e "${cfg.stateDir}/log4j2.xml"; then
+          install -D -m0640 ${cfg.package}/server/resources/log4j2.xml "${cfg.stateDir}/log4j2.xml"
+        fi
+      '';
+
+      serviceConfig = {
+        User = cfg.user;
+        Group = cfg.group;
+        ExecStart="${cfg.package}/bin/solr start -f -a \"${concatStringsSep " " cfg.extraJavaOptions}\"";
+        ExecStop="${cfg.package}/bin/solr stop";
+      };
     };
 
+    users.users = optionalAttrs (cfg.user == "solr") (singleton
+      { name = "solr";
+        group = cfg.group;
+        home = cfg.stateDir;
+        createHome = true;
+        uid = config.ids.uids.solr;
+      });
+
+    users.groups = optionalAttrs (cfg.group == "solr") (singleton
+      { name = "solr";
+        gid = config.ids.gids.solr;
+      });
+
   };
 
 }
diff --git a/nixos/modules/services/web-servers/tomcat.nix b/nixos/modules/services/web-servers/tomcat.nix
index be54e9255c78..68261c50324d 100644
--- a/nixos/modules/services/web-servers/tomcat.nix
+++ b/nixos/modules/services/web-servers/tomcat.nix
@@ -31,10 +31,26 @@ in
         '';
       };
 
+      purifyOnStart = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          On startup, the `baseDir` directory is populated with various files,
+          subdirectories and symlinks. If this option is enabled, these items
+          (except for the `logs` and `work` subdirectories) are first removed.
+          This prevents interference from remainders of an old configuration
+          (libraries, webapps, etc.), so it's recommended to enable this option.
+        '';
+      };
+
       baseDir = mkOption {
         type = lib.types.path;
         default = "/var/tomcat";
-        description = "Location where Tomcat stores configuration files, webapplications and logfiles";
+        description = ''
+          Location where Tomcat stores configuration files, web applications
+          and logfiles. Note that it is partially cleared on each service startup
+          if `purifyOnStart` is enabled.
+        '';
       };
 
       logDirs = mkOption {
@@ -197,6 +213,15 @@ in
       after = [ "network.target" ];
 
       preStart = ''
+        ${lib.optionalString cfg.purifyOnStart ''
+          # Delete most directories/symlinks we create from the existing base directory,
+          # to get rid of remainders of an old configuration.
+          # The list of directories to delete is taken from the "mkdir" command below,
+          # excluding "logs" (because logs are valuable) and "work" (because normally
+          # session files are there), and additionally including "bin".
+          rm -rf ${cfg.baseDir}/{conf,virtualhosts,temp,lib,shared/lib,webapps,bin}
+        ''}
+
         # Create the base directory
         mkdir -p \
           ${cfg.baseDir}/{conf,virtualhosts,logs,temp,lib,shared/lib,webapps,work}
diff --git a/nixos/modules/system/activation/activation-script.nix b/nixos/modules/system/activation/activation-script.nix
index 0ed7c0f53eb9..74c150a848d1 100644
--- a/nixos/modules/system/activation/activation-script.nix
+++ b/nixos/modules/system/activation/activation-script.nix
@@ -22,6 +22,7 @@ let
       gnugrep
       findutils
       getent
+      stdenv.cc.libc # nscd in update-users-groups.pl
       shadow
       nettools # needed for hostname
       utillinux # needed for mount and mountpoint
diff --git a/nixos/modules/virtualisation/amazon-image.nix b/nixos/modules/virtualisation/amazon-image.nix
index c92570582f20..9015200beead 100644
--- a/nixos/modules/virtualisation/amazon-image.nix
+++ b/nixos/modules/virtualisation/amazon-image.nix
@@ -53,7 +53,7 @@ let cfg = config.ec2; in
     # Mount all formatted ephemeral disks and activate all swap devices.
     # We cannot do this with the ‘fileSystems’ and ‘swapDevices’ options
     # because the set of devices is dependent on the instance type
-    # (e.g. "m1.large" has one ephemeral filesystem and one swap device,
+    # (e.g. "m1.small" has one ephemeral filesystem and one swap device,
     # while "m1.large" has two ephemeral filesystems and no swap
     # devices).  Also, put /tmp and /var on /disk0, since it has a lot
     # more space than the root device.  Similarly, "move" /nix to /disk0
diff --git a/nixos/modules/virtualisation/docker-preloader.nix b/nixos/modules/virtualisation/docker-preloader.nix
new file mode 100644
index 000000000000..faa94f53d98f
--- /dev/null
+++ b/nixos/modules/virtualisation/docker-preloader.nix
@@ -0,0 +1,135 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+with builtins;
+
+let
+  cfg = config.virtualisation;
+
+  sanitizeImageName = image: replaceStrings ["/"] ["-"] image.imageName;
+  hash = drv: head (split "-" (baseNameOf drv.outPath));
+  # The label of an ext4 FS is limited to 16 bytes
+  labelFromImage = image: substring 0 16 (hash image);
+
+  # The Docker image is loaded and some files from /var/lib/docker/
+  # are written into a qcow image.
+  preload = image: pkgs.vmTools.runInLinuxVM (
+    pkgs.runCommand "docker-preload-image-${sanitizeImageName image}" {
+      buildInputs = with pkgs; [ docker e2fsprogs utillinux curl kmod ];
+      preVM = pkgs.vmTools.createEmptyImage {
+        size = cfg.dockerPreloader.qcowSize;
+        fullName = "docker-deamon-image.qcow2";
+      };
+    }
+    ''
+      mkfs.ext4 /dev/vda
+      e2label /dev/vda ${labelFromImage image}
+      mkdir -p /var/lib/docker
+      mount -t ext4 /dev/vda /var/lib/docker
+
+      modprobe overlay
+
+      # from https://github.com/tianon/cgroupfs-mount/blob/master/cgroupfs-mount
+      mount -t tmpfs -o uid=0,gid=0,mode=0755 cgroup /sys/fs/cgroup
+      cd /sys/fs/cgroup
+      for sys in $(awk '!/^#/ { if ($4 == 1) print $1 }' /proc/cgroups); do
+        mkdir -p $sys
+        if ! mountpoint -q $sys; then
+          if ! mount -n -t cgroup -o $sys cgroup $sys; then
+            rmdir $sys || true
+          fi
+        fi
+      done
+
+      dockerd -H tcp://127.0.0.1:5555 -H unix:///var/run/docker.sock &
+
+      until $(curl --output /dev/null --silent --connect-timeout 2 http://127.0.0.1:5555); do
+        printf '.'
+        sleep 1
+      done
+
+      docker load -i ${image}
+
+      kill %1
+      find /var/lib/docker/ -maxdepth 1 -mindepth 1 -not -name "image" -not -name "overlay2" | xargs rm -rf
+    '');
+
+  preloadedImages = map preload cfg.dockerPreloader.images;
+
+in
+
+{
+  options.virtualisation.dockerPreloader = {
+    images = mkOption {
+      default = [ ];
+      type = types.listOf types.package;
+      description =
+      ''
+        A list of Docker images to preload (in the /var/lib/docker directory).
+      '';
+    };
+    qcowSize = mkOption {
+      default = 1024;
+      type = types.int;
+      description =
+      ''
+        The size (MB) of qcow files.
+      '';
+    };
+  };
+
+  config = {
+    assertions = [{
+      # If docker.storageDriver is null, Docker choose the storage
+      # driver. So, in this case, we cannot be sure overlay2 is used.
+      assertion = cfg.dockerPreloader.images == []
+        || cfg.docker.storageDriver == "overlay2"
+        || cfg.docker.storageDriver == "overlay"
+        || cfg.docker.storageDriver == null;
+      message = "The Docker image Preloader only works with overlay2 storage driver!";
+    }];
+
+    virtualisation.qemu.options =
+      map (path: "-drive if=virtio,file=${path}/disk-image.qcow2,readonly,media=cdrom,format=qcow2")
+      preloadedImages;
+
+
+    # All attached QCOW files are mounted and their contents are linked
+    # to /var/lib/docker/ in order to make image available.
+    systemd.services.docker-preloader = {
+      description = "Preloaded Docker images";
+      wantedBy = ["docker.service"];
+      after = ["network.target"];
+      path = with pkgs; [ mount rsync jq ];
+      script = ''
+        mkdir -p /var/lib/docker/overlay2/l /var/lib/docker/image/overlay2
+        echo '{}' > /tmp/repositories.json
+
+        for i in ${concatStringsSep " " (map labelFromImage cfg.dockerPreloader.images)}; do
+          mkdir -p /mnt/docker-images/$i
+
+          # The ext4 label is limited to 16 bytes
+          mount /dev/disk/by-label/$(echo $i | cut -c1-16) -o ro,noload /mnt/docker-images/$i
+
+          find /mnt/docker-images/$i/overlay2/ -maxdepth 1 -mindepth 1 -not -name l\
+             -exec ln -s '{}' /var/lib/docker/overlay2/ \;
+          cp -P /mnt/docker-images/$i/overlay2/l/* /var/lib/docker/overlay2/l/
+
+          rsync -a /mnt/docker-images/$i/image/ /var/lib/docker/image/
+
+          # Accumulate image definitions
+          cp /tmp/repositories.json /tmp/repositories.json.tmp
+          jq -s '.[0] * .[1]' \
+            /tmp/repositories.json.tmp \
+            /mnt/docker-images/$i/image/overlay2/repositories.json \
+            > /tmp/repositories.json
+        done
+
+        mv /tmp/repositories.json /var/lib/docker/image/overlay2/repositories.json
+      '';
+      serviceConfig = {
+        Type = "oneshot";
+      };
+    };
+  };
+}
diff --git a/nixos/modules/virtualisation/google-compute-image.nix b/nixos/modules/virtualisation/google-compute-image.nix
index caaf6c0aa59d..795858e5eae2 100644
--- a/nixos/modules/virtualisation/google-compute-image.nix
+++ b/nixos/modules/virtualisation/google-compute-image.nix
@@ -144,7 +144,6 @@ in
     path = with pkgs; [ iproute ];
     serviceConfig = {
       ExecStart = "${gce}/bin/google_network_daemon --debug";
-      Type = "oneshot";
     };
   };
 
diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix
index 4e9c87222d0a..ed3431554be4 100644
--- a/nixos/modules/virtualisation/qemu-vm.nix
+++ b/nixos/modules/virtualisation/qemu-vm.nix
@@ -185,7 +185,10 @@ let
 in
 
 {
-  imports = [ ../profiles/qemu-guest.nix ];
+  imports = [
+    ../profiles/qemu-guest.nix
+   ./docker-preloader.nix
+  ];
 
   options = {