Metrics

Fedora offers optional server metrics using Prometheus.

To enable metrics collection, the fcrepo.metrics.enable property must be set to true. For example, you could start Fedora with the argument -Dfcrepo.metrics.enable=true. With this option on, Fedora now exposes an endpoint that can be used by Prometheus to collect metrics. The endpoint is at http://[FCREPO-HOST]/prometheus.

Example Metrics Collection Setup

The following is an example of how you could setup Prometheus and Grafana using Docker to collect and monitor Fedora metrics. It is a quick and easy setup, and not intended to demonstrate a production ready install. This setup assumes that you already have Docker and Docker Compose installed on your system.

Linux Setup

Create a Prometheus config file, named prometheus.yml, that looks similar to the following:

scrape_configs:
  - job_name: 'fcrepo'
    scrape_interval: 30s
    metrics_path: '/prometheus'
    static_configs:
    - targets: ['localhost:8080']
    basic_auth:
      username: fedoraAdmin
      password: fedoraAdmin

Next, create a Docker compose file in the same directory, named docker-compose.yml,that looks like the following:

version: '3.8'
services:
 prometheus:
   image: prom/prometheus
   ports:
     - "9090:9090"
   volumes:
     - ./prometheus.yml:/etc/prometheus/prometheus.yml
   network_mode: "host"
    
 grafana:
   image: grafana/grafana
   ports:
   - "3000:3000"
   network_mode: "host"

Mac (Windows?) Setup

Create a Prometheus config file, named prometheus.yml, that looks similar to the following:

scrape_configs:
  - job_name: 'fcrepo'
    scrape_interval: 30s
    metrics_path: '/prometheus'
    static_configs:
    - targets: ['host.docker.internal:8080']
    basic_auth:
      username: fedoraAdmin
      password: fedoraAdmin

Next, create a Docker compose file in the same directory, named docker-compose.yml,that looks like the following:

version: '3.8'
services:
 prometheus:
   image: prom/prometheus
   ports:
     - "9090:9090"
   volumes:
     - ./prometheus.yml:/etc/prometheus/prometheus.yml
    
 grafana:
   image: grafana/grafana
   ports:
   - "3000:3000"

Collecting Metrics

From within this directory, execute docker-compose up to startup the services. You can confirm the services started by browsing to http://localhost:9090, the Prometheus endpoint, and http://localhost:3000, the Grafana endpoint.

Note, this will run the process in the foreground. If you prefer to run it in the background, use the -d flag.

The final bit of setup is to connect Grafana to Prometheus as follows:

1. Log into Grafana with the default credentials: admin/admin
2. Navigate to Configuration -> Datasources
3. Add a Prometheus datasource
4. For the Prometheus URL, if you're on linux specify http://localhost:9090, and if you're on Mac use http://host.docker.internal:9090. For amazon linux 2 use http://prometheus:9090
5. Save the configuration

Now that you have the datasource added, you can create a dashboard to display metrics from Fedora. Here is an example dashboard that you can import with some pre-configured graphs. You will need to actively use Fedora before any graphs will appear.