A Day in the Life of a DevOps Engineer: How a Simple S3 Upload Took Down a Chatbot

In DevOps, the big outages rarely come from big failures. They come from the tiny things—small enough to slip past everyone’s radar, big enough to break everything.

This is one of those days.

The Morning Quiet… Until It Isn’t

The day started as most do: coffee, stand-up, mentally preparing to tackle a mountain of tasks.

Then came the message no engineer loves:

“The chatbot is down on multiple customer sites.”

Time to dive in.

Within minutes, one thing was obvious: every page attempting to load the chatbot was throwing a 403 Forbidden error for a file called bundle.beta.js.

A 403 usually means one thing:
access denied.

So we didn’t have a code bug.
We had a permission problem.

The Investigation Begins

I checked the S3 bucket where the chatbot’s JavaScript bundle lives.

The file was present.
The version was correct.
But the permissions?

Public read access was missing.

You don’t need a crystal ball to know what happens when a public website tries to load a private JavaScript file:

  • Browser asks for the bundle
  • S3 says “nope”
  • Chatbot disappears from every page that depends on it

Mystery solved.
But the real question remained:

How did the permissions change in the first place?

The Smoking Gun: A Manual Upload

After checking deployment logs and Git history, I reviewed our meeting notes. That’s when it clicked:

We had recently updated the endpoint URLs in the frontend and someone had manually uploaded the new bundle file to S3.

Here’s the part many teams forget:

Manual S3 uploads do NOT retain previous ACL permissions unless explicitly set.

So the new file was uploaded with the default setting:
private.

Even when the previous version was re-uploaded, S3 didn’t automatically restore the original public access. Once locked down, it stayed locked down until someone fixed it manually.

It wasn’t a code regression.
It wasn’t a CI/CD failure.
It wasn’t a cloud bug.

It was simply a manual action with unexpected consequences.

A very human kind of outage.

The Fix

The fix itself took seconds:

  • Reapply public read permission to bundle.beta.js
  • Validate that browsers can load the bundle (200 OK, not 403)
  • Confirm that the chatbot reappears across all affected sites

Issue resolved.

But the learning?
That’s where the real value lies.

What This Incident Taught Us

1. Manual deployments are a ticking time bomb

Not because humans are bad at deploying—because they’re human.
And humans forget steps.

CI/CD doesn’t.

2. Permissions must be enforced in infrastructure, not in memory

If a deployment step isn’t captured in Terraform, CloudFormation, or the pipeline, it’s a liability.

3. A health check would have caught this instantly

A simple curl check to the bundle URL would have screamed “403” the second the file was uploaded.

4. Small steps cause big outages

This incident is a reminder that DevOps isn’t about fixing problems fast — it’s about designing systems where problems have fewer places to hide.

Toward a Better Deployment Pipeline

Here’s what we’re putting in place to prevent a repeat:

  • Move all JS bundle uploads into CI/CD
  • Enforce object permissions through Terraform
  • Add a post-deploy check to confirm the bundle is accessible
  • Disallow manual uploads to production buckets
  • Optionally, add a permission drift detector

None of these are big changes.
Together, they eliminate an entire class of incidents.

Why This Story Matters

People imagine DevOps as Kubernetes clusters, multi-cloud architectures, and complicated automation pipelines.

But the truth is simpler:

Most outages happen where automation ends and manual steps begin.

This case study is a perfect example of why teams need discipline around deployments—even for something as “harmless” as uploading a JavaScript file.

It’s also a reminder of what good DevOps really is:

  • Reducing friction
  • Eliminating guesswork
  • Turning lessons into systems
  • Protecting teams from avoidable mistakes

Sometimes DevOps is scaling infrastructure.
Sometimes it’s debugging Kubernetes.
And sometimes it’s spotting a permission checkbox that someone didn’t tick.

All part of the job.

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