Learning Objectives & Key Takeaways
0 / 4 Completed- Understand Kubernetes & Docker core architecture and runtime execution model
- Audit real-world latency, throughput benchmarks, and memory footprint
- Implement zero-downtime deployment patterns with resilience guards
- Verify code snippets and architect blueprints against production SLOs
- A readiness probe only stops traffic to a bad pod, it never restarts the container for you.
- RollingUpdate defaults to 25 percent maxUnavailable and maxSurge, which can be too loose for small replica counts.
- A PodDisruptionBudget protects pods only from voluntary disruptions like node drains, not from your own bad rollout.
- minReadySeconds catches pods that report Ready too early but crash seconds later under real load.
- kubectl rollout status is the only honest signal that your new version is actually serving traffic.
The 2 PM maintenance window nobody flagged as risky
Our platform team scheduled routine node maintenance for a Tuesday afternoon, cordoning and draining three nodes in a six node cluster. At the exact same time, a different team pushed a routine image bump to their checkout service Deployment. Nobody coordinated because nobody thought a node drain and an application rollout were related events worth coordinating.
Within ninety seconds, checkout pods were disappearing faster than new ones could become Ready. The rollout's own replacement pods were landing on the same nodes being drained, and the eviction controller was removing old pods with no PodDisruptionBudget to slow it down. Checkout returned 503s for just under four minutes during a flash sale.
- Readiness probes: the gate that decides who gets traffic
- Tuning RollingUpdate so maxUnavailable actually means something
- PodDisruptionBudgets protect against the disruption you forgot about
- A complete manifest you can apply and watch end to end
- When a rollout goes wrong, pause before you panic
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