{
  "id": 19129408,
  "title": "Our uptime check stayed green for forty minutes because CloudFront was answering it",
  "url": "https://urgent.news/2026/11/09/our-uptime-check-stayed-green-for-forty-minutes-because-cloudfront",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-11-09T09:40:40.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/sergey_shinder_ab2d943365/our-uptime-check-stayed-green-for-forty-minutes-because-cloudfront-was-answering-it-3bnp"
  },
  "original_language": "en",
  "account": null,
  "summary": "In October, a change to the load balancer's listener caused all requests to a storefront moving behind CloudFront to be sent to an empty target group, resulting in a 503 error for 42 minutes. However, the website's external uptime check remained green throughout this period, despite the outage. This was possible because CloudFront had cached the /health endpoint, which it served with a default TTL of 24 hours. The uptime check continued to record a 200 status code and a response time of around 70,000 seconds, indicating that the cached response was being served without reaching the origin. The outage was only discovered when a customer called the company. To address this issue, the /health endpoint now includes Cache-Control: no-store and has its own cache behavior with the CachingDisabled policy. This change ensures that the endpoint sends a fresh response that includes the instance name and the server's clock, allowing the monitor to detect if the response is stale or carries an Age header.",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}