Using Codex as a Sysadmin to Find a Cloudflare DNS Issue

Melvin Vivas · X post · 2026-08-28 · Open on X

Topics: AI Dev Tools & Productivity, LLMOps, Deployment & Monitoring · Level: intermediate

Summary

The creator used OpenAI Codex to look into a slow website. Codex found that the cause was a DNS configuration problem between Cloudflare and an AWS Application Load Balancer. The example shows coding agents being used for infrastructure troubleshooting, not just writing code.

Key points

• Symptom: a website was slow to respond.
• Codex traced the cause to a DNS config issue in Cloudflare pointing to an AWS ALB.
• Coding agents can work as sysadmin helpers for diagnosing infrastructure problems.

Resources mentioned

• OpenAI Codex · tool · openai.com · paid
  OpenAI's coding agent. In the diagram it writes code, fixes review findings and drives the build loop. The creator also used it to make this video.
  Also in: An agent bot that installs and drives Codex on its own (Melvin Vivas on X · notes), Asking a Coder bot to install Codex (Melvin Vivas on X · notes), Sign in with ChatGPT: Setting Usage Limits for Each App (Melvin Vivas on X · notes), Codex Cloud Environments Must Be Saved & Published Before Use (Melvin Vivas on X · notes) and 240 more
• Cloudflare · tool · x.com · check price
  Cloud platform listed as a supported BYOS sandbox provider.
  Also in: OpenAI Agents API with Bring Your Own Sandbox as a backend for a 'software factory' (Melvin Vivas on X · notes)
• AWS Application Load Balancer (ALB) · tool · aws.amazon.com · paid
  AWS's managed load balancer for HTTP and HTTPS traffic.