How to Prepare for a DevOps / SRE Interview in 2026

DevOps and SRE interviews have converged in 2026. Whether the role is titled "DevOps Engineer," "SRE," or "Platform Engineer," the interview content is similar — Linux/OS fundamentals, infrastructure as code, Kubernetes, observability, and incident response.

The DevOps/SRE Interview Loop

1. Technical screen — Linux/scripting + one infrastructure question (45 min)
2. Loop (4–5 rounds):
   • Linux and OS fundamentals
   • Coding (Python/Go/Bash scripting)
   • Infrastructure design / system design
   • Kubernetes and container orchestration
   • Incident response and observability
   • Behavioral / on-call culture fit

Linux & OS Fundamentals

Every DevOps/SRE interview tests Linux knowledge. Must-know topics:

Process management:

• ps, top, htop, kill, nice, renice
• Process states: running, sleeping, zombie, stopped
• fork() vs exec() — how processes are created
• File descriptors and lsof

Networking:

• TCP three-way handshake, FIN sequence
• netstat, ss, tcpdump, curl -v
• DNS resolution chain: /etc/hosts → local resolver → recursive → authoritative
• iptables / nftables basics, NAT, port forwarding
• Load balancing: L4 vs L7, connection vs request distribution

Storage:

• Filesystem types: ext4, XFS, tmpfs
• inodes, hard links vs symlinks
• df, du, iostat, lsblk
• LVM basics, RAID levels trade-offs

Common interview questions:

• "A server's load average is very high but CPU is not — what's happening?" (I/O wait)
• "How does DNS resolution work step by step?"
• "What happens when you run ssh user@host?"
• "How would you find which process is using port 8080?"

Kubernetes

Kubernetes is now table stakes for DevOps/SRE roles:

Core concepts:

• Pod, Deployment, ReplicaSet, DaemonSet, StatefulSet — when to use each
• Services: ClusterIP, NodePort, LoadBalancer, Headless
• ConfigMaps and Secrets — how they're injected, security implications
• PersistentVolumes and PersistentVolumeClaims
• Namespaces and RBAC

Advanced topics (senior roles):

• HPA vs VPA vs KEDA — horizontal vs vertical vs event-driven autoscaling
• Ingress controllers: NGINX, Traefik — routing rules, TLS termination
• Network policies — pod-to-pod traffic control
• Custom Resource Definitions (CRDs) and operators
• Helm: chart structure, templating, release management

Kubernetes troubleshooting questions:

• "A pod is in CrashLoopBackOff — how do you debug it?"
• "A deployment rollout is stuck — what commands do you run?"
• "How do you do zero-downtime deployments in Kubernetes?"

Infrastructure as Code

• Terraform: plan, apply, state, modules, remote state, terraform import
• Ansible: playbooks, roles, inventory, idempotency
• Pulumi: IaC with real programming languages — increasingly common
• GitOps: ArgoCD, Flux — declarative infrastructure from Git

Common question: "What are the trade-offs between Terraform and Ansible? When would you use each?"

CI/CD

• Pipeline design: build → test → security scan → staging deploy → prod deploy
• GitHub Actions, GitLab CI, Jenkins, CircleCI — know at least one deeply
• Deployment strategies: rolling, blue-green, canary — implement each in Kubernetes
• Artifact management: Docker registry, Nexus, Artifactory
• Secret management in pipelines: Vault, AWS Secrets Manager, sealed secrets

Observability

The three pillars: metrics, logs, traces.

• Metrics: Prometheus + Grafana, alerting rules, recording rules, SLO dashboards
• Logging: ELK/EFK stack, Loki, structured logging, log aggregation patterns
• Tracing: Jaeger, Zipkin, OpenTelemetry — distributed trace propagation
• SLIs, SLOs, SLAs: Define them, measure them, set error budgets

Incident response questions:

• "Walk me through how you'd investigate a 50% increase in 5xx errors."
• "How do you write a post-mortem? What makes a good one?"
• "What's your on-call philosophy? How do you prevent alert fatigue?"

6-Week DevOps/SRE Prep Plan

| Week | Focus | |------|-------| | 1 | Linux fundamentals + 20 Linux interview questions | | 2 | Kubernetes: core + advanced topics, kubectl fluency | | 3 | Terraform + CI/CD pipeline design | | 4 | Observability stack: Prometheus, Grafana, distributed tracing | | 5 | Infrastructure system design: 3 full designs | | 6 | Mock loops + incident response scenarios |

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