claude-sonnet-4.6 × roleplay

{
  "response": "Take a breath — intermittent 502s after a deployment are very common and almost always diagnosable without drastic action. Docker itself is rarely broken; something in the environment or configuration changed, and we're going to find it methodically.",
  "diagnostic_questions": [
    "What exactly changed in this deployment — did you update the image, docker-compose config, environment variables, exposed ports, or any reverse proxy config like Nginx or Traefik?",
    "When the 502 occurs, is it completely random or does it follow a pattern — for example, right after a cold start, under load, or after a period of inactivity?",
    "What do the logs show at the moment a 502 is triggered — specifically from both the reverse proxy (e.g., Nginx) and the Node.js container itself?"
  ],
  "triage_steps": [
    "Step 1 — Check container health: Run `docker ps` to confirm the Node.js container is actually running and not in a restart loop, then run `docker inspect <container_name>` to verify its health status and uptime.",
    "Step 2 — Tail live logs: Run `docker logs --tail=100 -f <container_name>` and simultaneously trigger a few requests to capture what the app logs at the exact moment a 502 occurs — look for crashes, unhandled rejections, or port binding errors.",
    "Step 3 — Verify the reverse proxy config: Check your Nginx or proxy configuration to confirm the `proxy_pass` target (host and port) still matches what the container is actually exposing — a port mismatch after a config change is a very common cause of 502s.",
    "Step 4 — Test the Node.js app directly: Temporarily curl the Node.js service directly on its internal port (e.g., `curl http://localhost:3000/health`) from inside the VPS or container network to determine whether the issue is in the app itself or in the proxy layer in front of it.",
    "Step 5 — Review resource constraints: Run `docker stats` and `free -m` to check if the container is hitting memory limits or if the VPS is under CPU/memory pressure, which can cause the Node process to become unresponsive intermittently."
  ],
  "likely_evidence_needed": "If the direct curl to the Node.js port succeeds consistently but requests through the proxy intermittently fail, that confirms the issue lives in the reverse proxy configuration, not in Docker or the application itself."
}