Design and explain infra, K8s, routing, and fleet
Overview
This question evaluates system design and infrastructure engineering skills, including Infrastructure-as-Code and CI/CD for bare-metal and Kubernetes, secrets management, idempotency and drift control, Kubernetes control-plane and workload management, edge firmware and fleet OTA management, IP routing and troubleshooting, and the ability to demonstrate automation, networking, observability, and security through a homelab. It is commonly asked to assess operational design thinking, scalability, security, reliability, and troubleshooting across distributed systems, falls under the System Design and Platform Engineering domain, and tests both conceptual understanding of control-plane and networking principles and practical application of operational guardrails and rollout strategies.
System Design and Operations Deep-Dive
Context: You are interviewing for a Software Engineer role with a focus on system design and engineering. Provide concise, design-oriented answers with justifications and operational guardrails.
1) Infrastructure as Code (IaC) and CI/CD for Bare Metal and Kubernetes
Describe a reference design to provision and update bare-metal servers and Kubernetes clusters via CI/CD. Address:
- Secrets management (bootstrapping, in-cluster, and at-rest)
- Idempotency and safe rollouts
- Drift detection and policy enforcement
2) Kubernetes Control Plane and Workload Management
- Explain Kubernetes’ reconciliation loop and how controllers converge desired vs. observed state.
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Outline strategies for workload management:
- Scheduling primitives (affinity/anti-affinity, taints/tolerations, topology spread)
- Resource requests/limits and LimitRanges
- ResourceQuotas and fair-share
- Horizontal Pod Autoscaler (HPA) and Vertical Pod Autoscaler (VPA)
- Cluster Autoscaler (CA)
- Multi-tenancy models and recommended guardrails
3) Edge Firmware/Fleet Management
Design and operate a solution for edge devices that supports:
- Secure OTA updates (signing, A/B, deltas)
- Staged rollouts and canarying
- Automatic rollback and break-glass procedures
- Device identity, health telemetry, and fleet observability
4) IP Routing and Troubleshooting
- Explain routing tables and longest-prefix match. Contrast static vs. dynamic routing.
- Troubleshoot blackholes and asymmetric routing; list diagnostic steps and mitigations.
5) Homelab
Share a practical homelab setup that demonstrates your skills across automation, Kubernetes, networking, observability, and security. Explain what it proves about your capabilities.
Solution
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