diff --git a/site-cookbooks/kosmos_prometheus/attributes/default.rb b/site-cookbooks/kosmos_prometheus/attributes/default.rb
index added9b..5851470 100644
--- a/site-cookbooks/kosmos_prometheus/attributes/default.rb
+++ b/site-cookbooks/kosmos_prometheus/attributes/default.rb
@@ -33,6 +33,8 @@ node.default["kosmos_prometheus"]["alertmanager"]["route"] = {
   ],
 }
 
+node.default["kosmos_prometheus"]["alertmanager"]["port"] = 9093
+
 node.default["kosmos_prometheus"]["alertmanager"]["receivers"] = [
   {
     "name" => "xmpp",
@@ -65,7 +67,7 @@ node.default["kosmos_prometheus"]["global"] = {
 node.default["kosmos_prometheus"]["alerting"] = {
   "alertmanagers" => [
     "static_configs" => [
-      { "targets" => ["127.0.0.1:9093"] }
+      { "targets" => ["127.0.0.1:#{node["kosmos_prometheus"]["alertmanager"]["port"]}"] }
     ]
   ]
 }
diff --git a/site-cookbooks/kosmos_prometheus/recipes/alertmanager.rb b/site-cookbooks/kosmos_prometheus/recipes/alertmanager.rb
index 9ad9799..b8625a9 100644
--- a/site-cookbooks/kosmos_prometheus/recipes/alertmanager.rb
+++ b/site-cookbooks/kosmos_prometheus/recipes/alertmanager.rb
@@ -10,6 +10,8 @@ checksum = node["kosmos_prometheus"]["alertmanager"]["checksum"]
 tarball = "#{Chef::Config[:file_cache_path]}/alertmanager-#{version}.linux-amd64.tar.gz"
 binary_url = "https://github.com/prometheus/alertmanager/releases/download/v#{version}/alertmanager-#{version}.linux-amd64.tar.gz"
 
+alertmanager_port = node["kosmos_prometheus"]["alertmanager"]["port"]
+
 group "alertmanager"
 
 user "alertmanager" do
@@ -81,7 +83,7 @@ systemd_unit "alertmanager.service" do
       Type: "simple",
       User: "alertmanager",
       Group: "alertmanager",
-      ExecStart: "/usr/local/bin/alertmanager --config.file=/etc/prometheus/alertmanager.yml --storage.path=/var/lib/alertmanager --web.listen-address=:9093",
+      ExecStart: "/usr/local/bin/alertmanager --config.file=/etc/prometheus/alertmanager.yml --storage.path=/var/lib/alertmanager --web.listen-address=:#{alertmanager_port}",
       Restart: "on-failure",
       RestartSec: "5",
     },
@@ -98,7 +100,7 @@ service "alertmanager" do
 end
 
 firewall_rule "prometheus alertmanager" do
-  port 9093
+  port alertmanager_port
   source "10.1.1.0/24"
   protocol :tcp
   command :allow