diff --git a/krebs/2configs/default.nix b/krebs/2configs/default.nix
index e7ece87b6..c3400e171 100644
--- a/krebs/2configs/default.nix
+++ b/krebs/2configs/default.nix
@@ -5,6 +5,7 @@ with import <stockholm/lib>;
   imports = [
     ./backup.nix
   ];
+  krebs.announce-activation.enable = true;
   krebs.enable = true;
   krebs.tinc.retiolum.enable = true;
 
diff --git a/krebs/3modules/announce-activation.nix b/krebs/3modules/announce-activation.nix
new file mode 100644
index 000000000..5a3a788c2
--- /dev/null
+++ b/krebs/3modules/announce-activation.nix
@@ -0,0 +1,60 @@
+with import <stockholm/lib>;
+{ config, pkgs, ... }: let
+  cfg = config.krebs.announce-activation;
+  announce-activation = pkgs.writeDash "announce-activation" ''
+    set -efu
+    message=$(${cfg.get-message})
+    exec ${pkgs.irc-announce}/bin/irc-announce \
+        ${shell.escape cfg.irc.server} \
+        ${shell.escape (toString cfg.irc.port)} \
+        ${shell.escape cfg.irc.nick} \
+        ${shell.escape cfg.irc.channel} \
+        "$message"
+  '';
+  default-get-message = pkgs.writeDash "announce-activation-get-message" ''
+    set -efu
+    PATH=${makeBinPath [
+      pkgs.coreutils
+      pkgs.gawk
+      pkgs.gnused
+      pkgs.nix
+    ]}
+    profile=/nix/var/nix/profiles/system
+    gen_info=$(nix-env -p "$profile" --list-generations | tail -1)
+    gen_no=$(echo "$gen_info" | awk '{print$1}')
+    pretty_name=$(sed -n '/^PRETTY_NAME=/{s/.*="//;s/"$//;p}' /etc/os-release)
+    echo "activating generation $gen_no $pretty_name"
+  '';
+in {
+  options.krebs.announce-activation = {
+    enable = mkEnableOption "announce-activation";
+    get-message = mkOption {
+      default = default-get-message;
+      type = types.package;
+    };
+    irc = {
+      # TODO rename channel to target?
+      channel = mkOption {
+        default = "#retiolum";
+        type = types.str; # TODO types.irc-channel
+      };
+      nick = mkOption {
+        default = config.krebs.build.host.name;
+        type = types.label;
+      };
+      port = mkOption {
+        default = 6667;
+        type = types.int;
+      };
+      server = mkOption {
+        default = "ni.r";
+        type = types.hostname;
+      };
+    };
+  };
+  config = mkIf cfg.enable {
+    system.activationScripts.announce-activation = ''
+      ${announce-activation}
+    '';
+  };
+}
diff --git a/krebs/3modules/default.nix b/krebs/3modules/default.nix
index abb3d37eb..42df3f053 100644
--- a/krebs/3modules/default.nix
+++ b/krebs/3modules/default.nix
@@ -6,6 +6,7 @@ let
 
   out = {
     imports = [
+      ./announce-activation.nix
       ./apt-cacher-ng.nix
       ./backup.nix
       ./bepasty-server.nix