The AWS Outage Wasn't a Failure of Infrastructure : It Was a Failure of Premeditatio Malorum

When AWS’s control plane went down last month, it wasn’t just another outage: it was a wake-up call for every architect. Thousands of systems that were supposed to be “resilient” collapsed instantly. Multi-AZ deployments didn’t help. Auto-scaling didn’t trigger. Failover mechanisms froze because the orchestrators themselves were down.

In short: the cloud ate itself.

This isn’t just about AWS. It’s about the way we design systems, and the assumptions we make. Or, in Stoic terms, it’s about our failure of premeditatio malorum : the practice of imagining disasters in advance so that we can withstand them.

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Fallacies of Distributed Computing : Revisited

Sun Microsystems documented the 8 Fallacies of Distributed Computing decades ago. They still apply, painfully:

1. The network is reliable → DNS disagrees.
2. Latency is zero → Retry storms prove otherwise.
3. Bandwidth is infinite → Until congestion collapses your backplane.
4. The network is secure → When failover automation can’t reach IAM, security becomes irrelevant.
5. Topology doesn’t change → Until internal routing updates break assumptions.
6. There is one administrator → And it’s never you.
7. Transport cost is zero → Cross-region data transfer proves otherwise.
8. The network is homogeneous → Vendor lock-in and hidden dependencies expose fragility.

Every outage reminds us that these fallacies are real, not academic exercises.

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Designing for Real Resilience

Many organizations “deploy across multiple AZs” and call it resilient. That’s naive. Real resilience comes from independence, not redundancy.

Key patterns:

• Bulkheads: Isolate failures within subsystems to prevent cascading collapse.
• Circuit breakers & backpressure: Stop amplification before it overwhelms the system.
• Out-of-band recovery paths: Ensure control and observation exist even when the primary platform fails.
• Active-active cross-region deployments: Not just code deployed, but traffic actively routed and tested.
• Human playbooks: Automation fails. Humans must rehearse disaster scenarios like pilots.

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Chaos Engineering: The Discipline of Breaking Systems

Netflix pioneered Simian Army years ago:

• Chaos Monkey randomly kills instances.
• Latency Monkey injects delay.
• Conformity Monkey tests dependency assumptions.
• Chaos Gorilla simulates entire availability-zone failures.
• Chaos Kong simulates entire region failures.

The goal: rehearse failure before production forces it on you.

If you never break your own system, you don’t know where it’s weak. And if your chaos experiments are convenient or partial, you’re training for the wrong failures.

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Visualizing Failure Propagation

Here’s a Mermaid diagram showing how a single control-plane failure can cascade through a system:

graph TD
    A[User Request] --> B[Load Balancer]
    B --> C1[App Server 1]
    B --> C2[App Server 2]
    C1 --> D[Database]
    C2 --> D
    D --> E[Control Plane Dependency]
    E --> F[Failure Propagation]
    F --> G[System Outage]

And here’s a Chaos Monkey style sequence:

sequenceDiagram
    participant CM as Chaos Monkey
    participant AS as App Server
    participant DB as Database
    participant LB as Load Balancer

    CM->>AS: Randomly terminate instance
    AS->>LB: Report unhealthy
    LB->>AS: Reroute traffic
    AS->>DB: Retry queries
    DB->>AS: Slow response / timeout
    AS->>CM: Failure propagates

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Lessons from the AWS Outage

1. Visibility is everything: You can’t defend what you can’t see.
2. Assume failure at all layers: Even control planes fail.
3. Test the worst-case scenario: Not just single-instance failure, but regional, provider-wide, or orchestration-layer failures.
4. Design humans into the loop: Automation alone isn’t enough; humans must be able to respond.
5. Learn from history: Distributed computing fallacies, chaos engineering principles, and Stoic practices like premeditatio malorum exist for a reason: they work.

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Closing Thought

Architecture is more than diagrams and standards. It’s a mindset of anticipation, humility, and preparation.

The AWS outage didn’t teach us anything new. It merely exposed who actually believes the principles we all claim to know.

Before your next system design session, ask yourself:

Which assumptions am I still pretending are true?

Thanks for sticking with me till the end.

B.