Show Docker Daemon metrics in Prometheus

developer-tools/java/chapters/ch10-monitoring.adoc

@@ -250,14 +250,17 @@ In this section, we'll start Prometheus and use it to scrape it's own health.
 . Create a text file `prometheus.yml` and use the following content
 +
 ```
-# A scrape configuration scraping a Node Exporter and the Prometheus server
-# itself.
 scrape_configs:
   # Scrape Prometheus itself every 5 seconds.
   - job_name: 'prometheus'
     scrape_interval: 5s
     static_configs:
       - targets: ['localhost:9090']
+  # Scrape Docker-Daemon every 10s
+  - job_name: 'docker-for-mac'
+    scrape_interval: 10s
+    static_configs:
+      - targets: ['docker.for.mac.localhost:9323']
 ```
 +
 This configuration file scrapes data from the Prometheus container which will be started subsequently on port 9090.
@@ -311,6 +314,13 @@ image::prometheus-metrics6.png[]
 
 Multiple graphs can be added this way.
 
+==== Plot the Docker daemon internal metrics
+
+The experimental feature on the Docker deamon we enabled before, exposes various metrics about the daemon itself.
+For example the `engine_daemon_events_total` metric provides the number of events which happend on the Docker Daemon (see also the `docker system events` command).
+
+image::prometheus-metrics17.png[]
+
 === Node health
 
 In this section, we'll start Prometheus node exporter that will publish machine metrics. Then we'll use Prometheus to scrape its health information about the node running Docker.
@@ -358,6 +368,7 @@ scrape_configs:
     static_configs:
       - targets:
         - 'localhost:9090'
+
   - job_name: 'node resources'
     dns_sd_configs:
       - names: ['tasks.node']
@@ -851,4 +862,3 @@ The green bar indicates that the data source was added successfully.
 . Enter the following Prometheus query expressions in the query field. The graphs will referesh in a few seconds and will look like as shown:
 +
 image::grafana-metrics4.png[]
-