Deploying Prometheus on Railway

Prometheus is available as an official Docker image on Docker Hub. We can use it as a base image and layer in our configuration before deploying it on Railway. You find the resources for the Deployment here (opens in a new tab).

Create a GitHub repository and a Prometheus configuration file

We will use Railway's ability to deploy from a repository and Dockerfile features (opens in a new tab) to set up our Prometheus instance.

Create a file called prometheus.yml with the following contents:

prometheus.yml

scrape_configs:
  - job_name: my-app-name
    metrics_path: /metrics
    static_configs:
      # Replace the port with the port your /metrics endpoint is running on
      - targets: ["localhost:3000"]
    scrape_interval: 15s

See the Prometheus configuration reference (opens in a new tab) for full details. You can find an example config.yaml here (opens in a new tab).

Add a Dockerfile in the root of the repository

The below Dockerfile uses the base Prometheus image, loads our configuration, makes the 9090 port available, and runs the container as a root user in Docker to make sure it can access the persistent volume properly.

FROM prom/prometheus:latest

ADD prometheus.yml /etc/prometheus/

EXPOSE 9090

USER root

Create a Railway service from a GitHub repo

Create a Railway service from our newly created GitHub repo, it should pick up the configuration from the Dockerfile

Add a PORT environment variable

In order to make Prometheus accessible to other services in your Railway project or externally (optional) - you need to tell Railway which port to listen on using the "magic" PORT environment variable.

To add it go to Service > Variables and add just the port number.

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