diff --git a/Dockerfile b/Dockerfile
index 50ea700..0bf72ce 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.9
+FROM python:3.7
 
 WORKDIR /app
 
diff --git a/docker-compose.test.yml b/docker-compose.test.yml
index c39472c..abdd40d 100644
--- a/docker-compose.test.yml
+++ b/docker-compose.test.yml
@@ -19,6 +19,7 @@ services:
       - sync1:sync
     volumes:
       - sync1config:/config
+      - etcd
     networks:
       - syncnet
 
@@ -38,6 +39,7 @@ services:
     build: .
     links:
       - sync2:sync
+      - etcd
     volumes:
       - sync2config:/config
     networks:
@@ -57,7 +59,7 @@ services:
 
   etcd:
     image: quay.io/coreos/etcd
-    command: /usr/local/bin/etcd --data-dir=/etcd-data
+    command: /usr/local/bin/etcd --data-dir=/etcd-data --advertise-client-urls http://etcd:2379 --listen-client-urls=http://0.0.0.0:2379
     volumes:
       - etcd-data:/etcd-data
     networks:
diff --git a/requirements.txt b/requirements.txt
index d5f6187..b219f5b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,3 @@
+etcd3
 retrying
 requests
diff --git a/syncthing_monitor/__main__.py b/syncthing_monitor/__main__.py
index 70c5e3d..f4c1e95 100644
--- a/syncthing_monitor/__main__.py
+++ b/syncthing_monitor/__main__.py
@@ -1,9 +1,9 @@
 from syncthing_monitor.config_xml import parse_api_key, set_listen_ip_to_any
+from syncthing_monitor.etcd_cluster_info import append_device_id
 from syncthing_monitor.syncthing_rest import get_device_id
 
 
 def loop(gui_port="8384", host="sync"):
-
     api_key = parse_api_key()
     print("Found API Key: {0}".format(api_key))
 
@@ -12,6 +12,8 @@ def loop(gui_port="8384", host="sync"):
     device_id = get_device_id(host, gui_port, api_key)
     print("Found Device ID: {0}".format(device_id))
 
+    append_device_id(device_id, 'etcd')
+
 
 if __name__ == "__main__":
     loop()
diff --git a/syncthing_monitor/etcd_cluster_info.py b/syncthing_monitor/etcd_cluster_info.py
new file mode 100644
index 0000000..a481b7d
--- /dev/null
+++ b/syncthing_monitor/etcd_cluster_info.py
@@ -0,0 +1,25 @@
+import json
+
+import etcd3 as etcd3
+from retrying import retry
+
+CLUSTER_INFO_KEY = '/syncthing_monitor/cluster_info'
+
+
+@retry
+def append_device_id(device_id, host, port=2379):
+    cluster_info = {'devices': []}
+
+    etcd = etcd3.client(host=host, port=port)
+
+    with etcd.lock('syncthing_monitor'):
+        raw_value = etcd.get(CLUSTER_INFO_KEY)[0]
+
+        if raw_value is not None:
+            cluster_info = json.loads(raw_value)
+
+        if not any(device_id in element for element in cluster_info['devices']):
+            cluster_info['devices'].append(device_id)
+
+        print("Updating etcd value for '{0}': {1}".format(CLUSTER_INFO_KEY, json.dumps(cluster_info)), flush=True)
+        etcd.put(CLUSTER_INFO_KEY, json.dumps(cluster_info))