Docker Compose healthcheck depends_on Condition Not Working: Why Your Container Starts Before Postgres Is Ready in 2026 Your app container crashes with ECONNREFUSED 127.0.0.1:5432 even though you set depends_on: postgres: condition: service_healthy, and the fix is almost always one of three things: you are on a Compose file format older than 2.1, your healthcheck block…
Docker Deployment Checklist: The Five Errors That Break a First Deploy The first deployment of a containerised app fails for a small set of reasons, and almost all of them are visible in the logs within thirty seconds. The problem is that the same three symptoms — the container exits immediately, the site does not…
Docker Compose Healthcheck Depends On Not Working: Fix for Node and Postgres Your Node container starts before Postgres is ready, crashes on the first query, and Compose reports a healthy stack while your app is dead. The fix is a healthcheck on the database plus depends_on with condition: service_healthy — and the reason it “doesn’t…
Docker Compose healthcheck depends_on not working: fix startup order for Postgres and Node Your Node container starts, tries to connect to Postgres, and dies with ECONNREFUSED — even though you wrote depends_on: [db]. The fix is a healthcheck plus the long-form depends_on syntax: services: db: image: postgres:17-alpine environment: POSTGRES_PASSWORD: devpass POSTGRES_USER: app POSTGRES_DB: app healthcheck:…
Docker Compose healthcheck depends_on condition service_healthy not working: the 2026 fix guide Your app container starts, your database container starts, and your app crashes with connection refused before Postgres finishes initializing. You added depends_on with condition: service_healthy and it still happens. Here is the working config first: services: db: image: postgres:16-alpine environment: POSTGRES_PASSWORD: devpass healthcheck:…
Last week, a junior developer on my team spent three days trying to deploy a simple Node.js app to a VPS. He had the right code. He had a server with Docker installed. But he got stuck on Dockerfile syntax, port mapping, and a confusing error about container names. I walked him through it in…
Containerizing a Python Flask app with Docker means packaging your Flask application, its dependencies, and runtime into a lightweight, portable container. This ensures your app runs consistently across any environment—from your laptop to a production server. In this beginner tutorial, you’ll learn to create a `Dockerfile`, build an image, and run your Flask app in…
Deploying a Node.js application with Docker involves creating a `Dockerfile`, building an image, and running a container. This end-to-end tutorial walks you through containerizing your Node.js app, optimizing the build process, and deploying it to production. By the end, you’ll have a fully Dockerized Node.js service that’s portable, scalable, and easy to manage. Docker simplifies…
The short answer: If you need scalability, flexibility, and enterprise-grade features, choose Kubernetes. If you want simplicity, fast setup, and native Docker integration, choose Docker Swarm. For most developers and small-to-medium teams, Docker Swarm wins on ease; for complex, production-grade deployments, Kubernetes is the clear leader. This guide breaks down both options so you can…