Knowledge base for software setup, errors, and daily tool work.

Cloudflare Wildcard Subdomain Troubleshooting Checklist

When you set up a wildcard DNS record (e.g., *.example.com) in Cloudflare, subdomain...

Git Push Rejected Non Fast Forward: Troubleshooting Checklist

Node.js --max-old-space-size Setup Guide for Memory Issues

If your Node.js process crashes with a JavaScript heap out of memory error, you likely need to ad...

Fix Docker Volume Permission Denied for Nginx

When running Nginx in a Docker container with a bind-mounted volume for static files, you might s...

Fix Cloudflare Origin Certificate with Let's Encrypt

If your origin server is rejecting the Cloudflare origin certificate—perhaps because of a SAN mis...

Passing Environment Variables to Docker Compose: A Practical Guide

When you run a multi-container application with Docker Compose, you often need to configure servi...