added config file for credentials and updated README.md how to use it and how to change the password correctly

Author: Phung Mike

README.md

@@ -1,7 +1,7 @@
 dockprom
 ========
 
-A monitoring solution for Docker hosts and containers with [Prometheus](https://prometheus.io/), [Grafana](http://grafana.org/), [cAdvisor](https://github.com/google/cadvisor), 
+A monitoring solution for Docker hosts and containers with [Prometheus](https://prometheus.io/), [Grafana](http://grafana.org/), [cAdvisor](https://github.com/google/cadvisor),
 [NodeExporter](https://github.com/prometheus/node_exporter) and alerting with [AlertManager](https://github.com/prometheus/alertmanager).
 
 ***If you're looking for the Docker Swarm version please go to [stefanprodan/swarmprom](https://github.com/stefanprodan/swarmprom)***
@@ -30,11 +30,28 @@ Containers:
 * Grafana (visualize metrics) `http://<host-ip>:3000`
 * NodeExporter (host metrics collector)
 * cAdvisor (containers metrics collector)
-* Caddy (reverse proxy and basic auth provider for prometheus and alertmanager) 
+* Caddy (reverse proxy and basic auth provider for prometheus and alertmanager)
 
 ## Setup Grafana
 
-Navigate to `http://<host-ip>:3000` and login with user ***admin*** password ***admin***. You can change the credentials in the compose file or by supplying the `ADMIN_USER` and `ADMIN_PASSWORD` environment variables on compose up.
+Navigate to `http://<host-ip>:3000` and login with user ***admin*** password ***admin***. You can change the credentials in the compose file or by supplying the `ADMIN_USER` and `ADMIN_PASSWORD` environment variables on compose up. The config file can be added directly in grafana part like this
+```
+grafana:
+  image: grafana/grafana:5.2.4
+  env_file:
+    - config
+
+```
+and the config file format should have this content
+```
+GF_SECURITY_ADMIN_USER=admin
+GF_SECURITY_ADMIN_PASSWORD=changeme
+GF_USERS_ALLOW_SIGN_UP=false
+```
+If you want to change the password, you have to remove this entry, otherwise the change will not take effect
+```
+- grafana_data:/var/lib/grafana
+```
 
 Grafana is preconfigured with dashboards and Prometheus as the default data source:
 
@@ -61,7 +78,7 @@ For storage and particularly Free Storage graph, you have to specify the fstype
 You can find it in `grafana/dashboards/docker_host.json`, at line 480 :
 
       "expr": "sum(node_filesystem_free_bytes{fstype=\"btrfs\"})",
-      
+
 I work on BTRFS, so i need to change `aufs` to `btrfs`.
 
 You can find right value for your system in Prometheus `http://<host-ip>:9090` launching this request :
@@ -109,7 +126,7 @@ I've set the Prometheus retention period to 200h and the heap size to 1GB, you c
       - '-storage.local.retention=200h'
 ```
 
-Make sure you set the heap size to a maximum of 50% of the total physical memory. 
+Make sure you set the heap size to a maximum of 50% of the total physical memory.
 
 ## Define alerts
 
@@ -226,15 +243,15 @@ ALERT jenkins_high_memory
 
 ## Setup alerting
 
-The AlertManager service is responsible for handling alerts sent by Prometheus server. 
-AlertManager can send notifications via email, Pushover, Slack, HipChat or any other system that exposes a webhook interface. 
+The AlertManager service is responsible for handling alerts sent by Prometheus server.
+AlertManager can send notifications via email, Pushover, Slack, HipChat or any other system that exposes a webhook interface.
 A complete list of integrations can be found [here](https://prometheus.io/docs/alerting/configuration).
 
 You can view and silence notifications by accessing `http://<host-ip>:9093`.
 
 The notification receivers can be configured in [alertmanager/config.yml](https://github.com/stefanprodan/dockprom/blob/master/alertmanager/config.yml) file.
 
-To receive alerts via Slack you need to make a custom integration by choose ***incoming web hooks*** in your Slack team app page. 
+To receive alerts via Slack you need to make a custom integration by choose ***incoming web hooks*** in your Slack team app page.
 You can find more details on setting up Slack integration [here](http://www.robustperception.io/using-slack-with-the-alertmanager/).
 
 Copy the Slack Webhook URL into the ***api_url*** field and specify a Slack ***channel***.
@@ -258,7 +275,7 @@ receivers:
 ## Sending metrics to the Pushgateway
 
 The [pushgateway](https://github.com/prometheus/pushgateway) is used to collect data from batch jobs or from services.
- 
+
 To push data, simply execute:
 
     echo "some_metric 3.14" | curl --data-binary @- http://user:password@localhost:9091/metrics/job/some_job
@@ -344,4 +361,4 @@ To run the grafana container as `user: 104` change your `docker-compose.yml` lik
       - monitor-net
     labels:
       org.label-schema.group: "monitoring"
-```
+```

config

@@ -0,0 +1,3 @@
+GF_SECURITY_ADMIN_USER=admin
+GF_SECURITY_ADMIN_PASSWORD=changeme
+GF_USERS_ALLOW_SIGN_UP=false