From b44a842d088241cab8539213c383fe9de3d1a4fa Mon Sep 17 00:00:00 2001
From: Alexandru Giurgiu <alex.giurgiu@gmail.com>
Date: Thu, 30 Mar 2017 13:03:28 +0300
Subject: [PATCH] added some information to the README and added Swarm
 placement constraints to the compose file

---
 README.md           | 19 ++++++++++++++++++-
 docker-compose.yaml | 10 ++++++++--
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index cc552fe..faaf67b 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,18 @@
-# prometheus-swarm-discovery
+# Prometheus-Swarm service discovery
+
+This is POC that demonstrates Prometheus service discovery in Docker Swarm. It is implemented as a standalone tool
+that writes the scrape targets to a file, that is then read by Prometheus. This uses the `<file_sd_config>` config
+directive available in Prometheus.
+
+The discovery tool expects to have access to the Swarm API using `/var/run/docker.sock`. The provided `docker-compose.yaml`
+is configured to mount the `docker.sock` file inside the container, and this requires that the `swarm-discover` container
+is placed on the Swarm manager node.
+
+## Run Prometheus and the Swarm discovery tool
+
+The only thing required to run Prometheus and the discovery tool is to launch a Swarm stack using the provided docker-compose.yaml
+file.
+
+```
+$ docker stack deploy -c docker-compose.yaml prometheus
+```
diff --git a/docker-compose.yaml b/docker-compose.yaml
index 9133e0b..63c0a19 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -9,6 +9,9 @@ services:
       - swarm-endpoints:/swarm-endpoints/
     labels:
         prometheus.ignore: "true"
+    placement:
+      constraints:
+        - node.role == manager
   prometheus:
     image: prom/prometheus:v1.5.2
     ports:
@@ -16,7 +19,10 @@ services:
     volumes:
       - ./prometheus-configs/:/etc/prometheus
       - swarm-endpoints:/etc/swarm-endpoints/
-    command: ["-storage.local.retention=48h", "-storage.local.memory-chunks=1048576", "-config.file=/etc/prometheus/prometheus.yaml"]
+    command: ["-storage.local.retention=2h", "-storage.local.memory-chunks=1048576", "-config.file=/etc/prometheus/prometheus.yaml"]
+    placement:
+      constraints:
+        - node.role == manager
 
 volumes:
-  swarm-endpoints:
\ No newline at end of file
+  swarm-endpoints: