--- title: "Deploy Prometheus | Open Source Monitoring, Datadog Alternative on Railway" description: "Self host Prometheus. Time-series metrics, alerting, PromQL & more" category: "Observability" url: https://railway.com/deploy/prometheus --- # Deploy Prometheus | Open Source Monitoring, Datadog Alternative on Railway Self host Prometheus. Time-series metrics, alerting, PromQL & more **[Deploy Prometheus | Open Source Monitoring, Datadog Alternative on Railway on Railway](https://railway.com/template/prometheus)** - **Creator:** Heimdall - **Category:** Observability - **Total deploys:** 2 ## Template content ### Prometheus https://cdn.jsdelivr.net/gh/homarr-labs/dashboard-icons/svg/prometheus.svg - **Source:** praveen-ks-2001/prometheus-railway - **Public domain:** Yes ## Documentation ![Prometheus logo](https://observability.thomasriley.co.uk/prometheus/what-is-prometheus/images/logo.png?classes=shadow&width=40pc) # Deploy and Host Prometheus on Railway Prometheus is the de-facto open source monitoring system and time-series database — it scrapes metrics from your services, stores them locally with high compression, and lets you query and alert on them via PromQL. Self-host Prometheus on Railway to keep application, infrastructure, and Kubernetes metrics in your own environment without per-host SaaS fees. The template wraps `prom/prometheus:v3.11.3` (custom Dockerfile at `praveen-ks-2001/prometheus-railway`) with bcrypt-hashed HTTP basic auth, an auto-generated default `prometheus.yml`, and a persistent `/prometheus` volume. Web UI, `/metrics`, `/api/v1/*`, and health endpoints are all protected — safe on the public internet. ## Getting Started with Prometheus on Railway After deploy, open the Railway domain — your browser prompts for HTTP basic auth. Log in with `ADMIN_USER` / `ADMIN_PASSWORD` from the Variables tab. The default config self-scrapes Prometheus on `localhost:9090`, so the UI is immediately useful: open **Status -> Targets** to confirm scrape health, then run a query like `up` from the Graph tab. To monitor your own services, write a `prometheus.yml`, base64-encode it (`base64 -w0 prometheus.yml`), paste into `PROMETHEUS_CONFIG_B64`, and redeploy. ![Prometheus dashboard screenshot](https://res.cloudinary.com/asset-cloudinary/image/upload/v1777752818/bdb9d593-f6b8-4998-a628-c996ffb6ec78.png) ## About Hosting Prometheus Prometheus is a CNCF graduated project originally built at SoundCloud. It pulls metrics over HTTP from instrumented targets (apps, exporters, Kubernetes pods), stores them in a local TSDB, and exposes PromQL for ad-hoc analysis, dashboards, and alert evaluation. Key features of self-hosted Prometheus on Railway: - Pull-based scraping with service discovery (static, DNS, file_sd) - PromQL — vectorised queries with rate, histogram, aggregation operators - Built-in TSDB, ~1KB per active series - Recording and alerting rules (Alertmanager-compatible) - Toggleable remote-write receiver and admin API - HTTP basic auth on every endpoint by default ## Why Deploy Prometheus on Railway - One-click deploy with `/prometheus` volume mounted automatically - Public HTTPS domain auto-issued, basic auth from first boot - Drop-in `prometheus.yml` via base64 env var — no SSH needed - Vertical scaling as active series grow - Pay only for the compute and storage you use - Private networking to scrape Railway services over `*.railway.internal` ## Common Use Cases for Self-Hosted Prometheus - Scrape Kubernetes clusters, Node Exporter, cAdvisor, and your own `/metrics` endpoints - Pair with Grafana for dashboards (Grafana data source with basic auth) - PromQL alerts evaluated on a schedule, fired to Alertmanager / Slack / PagerDuty - Ingest from edge agents (Grafana Agent, OpenTelemetry Collector, Vector) via remote_write - Replace Datadog/New Relic for metric pipelines without per-host billing ## Dependencies for Prometheus on Railway - **Prometheus** — built on `prom/prometheus:v3.11.3`, repackaged via custom Dockerfile at [praveen-ks-2001/prometheus-railway](https://github.com/praveen-ks-2001/prometheus-railway). Multi-stage build copies the static Prometheus binary onto `python:3.12-slim` for entrypoint scripting and `bcrypt` password hashing. ### Environment Variables Reference | Variable | Default | Purpose | |---|---|---| | `ADMIN_USER` | `admin` | Basic-auth username for UI and API | | `ADMIN_PASSWORD` | `${{secret(32)}}` | Basic-auth password (bcrypt-hashed) | | `PROMETHEUS_RETENTION_TIME` | `15d` | TSDB retention window | | `PROMETHEUS_RETENTION_SIZE` | `0` | Max TSDB size (`0` = uncapped) | | `PROMETHEUS_SCRAPE_INTERVAL` | `15s` | Default scrape interval | | `PROMETHEUS_EVALUATION_INTERVAL` | `15s` | Default rule evaluation interval | | `PROMETHEUS_LOG_LEVEL` | `info` | `debug`, `info`, `warn`, `error` | | `PROMETHEUS_ENABLE_ADMIN_API` | `false` | Enable snapshot/delete API | | `PROMETHEUS_ENABLE_REMOTE_WRITE_RECEIVER` | `false` | Accept `remote_write` | | `PROMETHEUS_CONFIG_B64` | (empty) | Base64 `prometheus.yml` override | ### Deployment Dependencies for Prometheus on Railway - Runtime: Go binary from `prom/prometheus:v3.11.3` - Source: [github.com/prometheus/prometheus](https://github.com/prometheus/prometheus) - Docker Hub: [prom/prometheus](https://hub.docker.com/r/prom/prometheus) - Custom wrapper: [github.com/praveen-ks-2001/prometheus-railway](https://github.com/praveen-ks-2001/prometheus-railway) - Docs: [prometheus.io/docs](https://prometheus.io/docs/) ## Hardware Requirements for Self-Hosting Prometheus | Resource | Minimum | Recommended | |---|---|---| | CPU | 0.5 vCPU | 1–2 vCPU | | RAM | 512 MB | 2 GB (~1KB per active series) | | Storage | 1 GB volume | 5–20 GB | | Runtime | Go 1.22 (bundled) | Go 1.22 (bundled) | 512 MB handles a few thousand series. Heavy Kubernetes fleets with millions of active series should plan ~1KB/series plus query headroom. ## Self-Hosting Prometheus with Docker The plain `prom/prometheus` image runs out of the box but has no auth — this template wraps it with basic auth for production. The simplest local equivalent: ``` docker run -d --name prometheus -p 9090:9090 \ -v prometheus_data:/prometheus \ prom/prometheus:v3.11.3 ``` To use a custom scrape config on Railway, write the YAML below, run `base64 -w0 prometheus.yml`, paste into `PROMETHEUS_CONFIG_B64`, and redeploy: ``` global: scrape_interval: 15s scrape_configs: - job_name: my-app static_configs: - targets: ['my-app.railway.internal:8080'] ``` The entrypoint decodes the config on every boot — no rebuild needed. ## How Much Does Prometheus Cost to Self-Host? Prometheus is 100% free under Apache 2.0 — no enterprise tier, no per-host fees, no metric ingestion limits. The only costs are infrastructure and engineering time. On Railway, expect a few dollars a month for a 512 MB / 1 GB volume instance scraping a handful of services. Compare to Grafana Cloud's metered pricing (~$6.50 per 1K active series after the free tier) or Datadog's $15+ per host per month. ## Prometheus vs Datadog vs Grafana Cloud vs VictoriaMetrics | | Prometheus (self-hosted) | Datadog | Grafana Cloud | VictoriaMetrics | |---|---|---|---|---| | License | Apache 2.0 | Proprietary SaaS | Proprietary SaaS | Apache 2.0 | | Pricing | Infra only | Per host + ingest | Per active series | Infra only | | PromQL | Native | Compatible | Native (Mimir) | Native | | Best for | Owning your stack | All-in-one APM | Managed Prom + Loki | High-cardinality | Self-hosted Prometheus wins on control, predictable cost, and PromQL-native pipelines. Pair with Grafana for dashboards and Alertmanager for routing. ## FAQ **What is Prometheus and why self-host it?** Prometheus is an open-source metrics database and monitoring system. Self-hosting on Railway keeps your metrics in your own environment, avoids per-host SaaS fees, and gives you full control over retention and scrape configs. **What does this Railway template deploy?** A single Prometheus service running `prom/prometheus:v3.11.3` behind HTTP basic auth, with a `/prometheus` volume for TSDB persistence and a base64 env var (`PROMETHEUS_CONFIG_B64`) to drop in your own scrape config. **Why does this Prometheus template require a persistent volume?** The TSDB writes blocks to `/prometheus` every two hours and compacts older blocks. Without a volume, every redeploy wipes your historical metrics. **How do I add custom scrape targets to self-hosted Prometheus on Railway?** Write a `prometheus.yml`, run `base64 -w0 prometheus.yml`, paste the output into `PROMETHEUS_CONFIG_B64`, and redeploy. The entrypoint decodes the config and starts Prometheus with it. **How do I connect Grafana to self-hosted Prometheus on Railway?** In Grafana, add a Prometheus data source pointing at `https://`, set auth type to Basic auth, and enter `ADMIN_USER` / `ADMIN_PASSWORD`. PromQL works identically to a local Prometheus. ## Similar templates - [Pyroscope profiling](https://railway.com/deploy/pyroscope-profiling) — Protected continuous profiling with durable Pyroscope storage. - [SigOnly](https://railway.com/deploy/sigonly) — Deploy SigNoz with a working demo app & config in one click - [Unwrapped Spotify Music Stats](https://railway.com/deploy/wide-bold) — Unwrapped Spotify Music Stats, Estatísticas de músicas disponíveis Open this page in a browser: https://railway.com/deploy/prometheus