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Deploying a PostHog App

Introduction

PostHog is an open-source product analytics platform with event capture, feature flags, and session replay. Deploying PostHog with a Dockerfile on Klutch.sh provides reproducible builds, managed secrets, and persistent storage for logs and artifacts—all configured from klutch.sh/app. This guide covers installation, repository prep, a production-ready Dockerfile, deployment steps, Nixpacks overrides, sample API usage, and production tips.

Prerequisites

  • A Klutch.sh account (sign up)
  • A GitHub repository containing your PostHog Dockerfile (GitHub is the only supported git source)
  • External services (recommended): PostgreSQL (deploy as a Klutch.sh TCP app on port 8000, connect on 5432), Redis (6379), Kafka (for ingestion), and ClickHouse (analytics database)
  • Domain and TLS for secure access

For onboarding, see the Quick Start.

Architecture and ports

  • PostHog web/API serves HTTP on internal port 8000; choose HTTP traffic and set the internal port to 8000.
  • Persistent storage is recommended for logs and any locally stored artifacts. Primary data resides in external Postgres/ClickHouse.

Repository layout

posthog/
├── Dockerfile              # Must be at repo root for auto-detection
└── README.md

Keep secrets out of Git; store them in Klutch.sh environment variables.

Installation (local) and starter commands

Validate locally before pushing to GitHub (ensure Postgres/Redis/ClickHouse/Kafka are reachable):

Terminal window
docker build -t posthog-local .
docker run -p 8000:8000 \
  -e DATABASE_URL=postgres://user:pass@localhost:5432/posthog \
  -e REDIS_URL=redis://localhost:6379 \
  -e CLICKHOUSE_HOST=localhost \
  -e CLICKHOUSE_USER=default \
  -e CLICKHOUSE_PASSWORD= \
  -e KAFKA_BROKER=localhost:9092 \
  posthog-local

Dockerfile for PostHog (production-ready)

Place this Dockerfile at the repo root; Klutch.sh auto-detects it (no Docker selection in the UI):

FROM posthog/posthog:latest


ENV PORT=8000


EXPOSE 8000
CMD ["bash", "-lc", "export PORT=${PORT}; /entrypoint.sh"]

Notes:

  • Pin the image tag (e.g., posthog/posthog:1.51.x) for stability; update intentionally.
  • The image expects external Postgres, Redis, Kafka, and ClickHouse endpoints via environment variables.

Environment variables (Klutch.sh)

Set these in Klutch.sh before deploying:

  • PORT=8000
  • DATABASE_URL=postgres://<user>:<password>@<db-host>:5432/<db>
  • REDIS_URL=redis://:<password>@<redis-host>:6379
  • CLICKHOUSE_HOST=<clickhouse-host>
  • CLICKHOUSE_PORT=9000
  • CLICKHOUSE_USER=<user>
  • CLICKHOUSE_PASSWORD=<password>
  • KAFKA_BROKER=<kafka-host>:9092
  • SECRET_KEY=<secure-random>
  • Optional: EMAIL_HOST, EMAIL_USER, EMAIL_PASSWORD, EMAIL_PORT, DEFAULT_FROM_EMAIL

If you deploy without the Dockerfile and need Nixpacks overrides:

  • NIXPACKS_START_CMD=/entrypoint.sh
  • NIXPACKS_NODE_VERSION=18

Attach persistent volumes

In Klutch.sh storage settings, add mount paths and sizes (no names required) if you store logs or artifacts locally:

  • /var/log/posthog — logs (optional).
  • /data — optional local artifact storage (most data lives in external DBs).

Ensure these paths are writable inside the container.

Deploy PostHog on Klutch.sh (Dockerfile workflow)

  1. Push your repository—with the Dockerfile at the root—to GitHub.
  2. Open klutch.sh/app, create a project, and add an app.
  3. Select HTTP traffic and set the internal port to 8000.
  4. Add the environment variables above, including Postgres, Redis, Kafka, ClickHouse, and secret key.
  5. Attach persistent volumes for /var/log/posthog (and /data if used) sized for your retention needs.
  6. Deploy. Your PostHog instance will be reachable at https://example-app.klutch.sh; attach a custom domain if desired.

Sample API usage

Capture an event:

Terminal window
curl -X POST "https://example-app.klutch.sh/capture/" \
  -H "Content-Type: application/json" \
  -d '{"api_key":"<project_api_key>","event":"test_event","properties":{"source":"klutch-guide"}}'

List events (replace token with personal API token):

Terminal window
curl -X GET "https://example-app.klutch.sh/api/event/" \
  -H "Authorization: Bearer <token>"

Health checks and production tips

  • Add an HTTP probe to /health or /api/feature_flag/ (simple read) for readiness.
  • Enforce HTTPS at the edge; forward internally to port 8000.
  • Keep DB, Redis, Kafka, and ClickHouse credentials plus SECRET_KEY in Klutch.sh secrets; rotate regularly.
  • Monitor external service health (Kafka/ClickHouse/Postgres) and storage usage on any attached volumes; resize before they fill.
  • Pin image versions and test upgrades in staging; back up databases before updates.

PostHog on Klutch.sh combines reproducible Docker builds with managed secrets, persistent storage, and flexible HTTP/TCP routing. With the Dockerfile at the repo root, port 8000 configured, and external services connected, you can deliver product analytics without extra YAML or workflow overhead.