# Top 50 DevOps & Kubernetes Interview Questions & Answers 2026 > Canonical Source: https://ratemyinterview.online/blog/devops-kubernetes-interview-questions-2026 > Platform: RateMyInterview (https://ratemyinterview.online) — Voice AI Mock Technical Interview Platform > Practice Live Out Loud: https://ratemyinterview.online/practice (2 free full sessions included, zero credit card required) DevOps & Cloud · 2026 Edition # Top 50 DevOps & Kubernetes Interview Questions & Answers for 2026 August 22, 2026 · 20 min read · RateMyInterview DevOps Experts ## Key Takeaways — DevOps & SRE Interviews 2026 - • **Kubernetes Architecture Mastery:** Deep knowledge of `kube-apiserver`, etcd Raft consensus, kube-scheduler filters, kube-controller-manager loops, and CNI plugins (Calico/Cilium) is tested in 90% of DevOps interviews. - • **IaC & Terraform State:** Terraform remote backend state locking with DynamoDB and S3, module versioning, drift detection, and `lifecycle { prevent_destroy = true }` rules. - • **Zero-Downtime Deployment Patterns:** Clear distinction between Rolling Updates, Blue-Green, Canary deployments with Flagger/Istio, and GitOps synchronization via ArgoCD. - • **Linux & Production Troubleshooting:** Systematic incident debugging using `strace`, `lsof`, `ss/netstat`, `tcpdump`, `journalctl`, and resolving `CrashLoopBackOff` and `OOMKilled` statuses. ## Table of Contents - [1. Kubernetes Cluster Architecture & Control Plane Internals](#k8s-architecture) - [2. Troubleshooting Pods: CrashLoopBackOff, OOMKilled & Pending](#pod-troubleshooting) - [3. Docker & Containerization: Multi-stage Builds & Security](#docker-containerization) - [4. Terraform & Infrastructure as Code Best Practices](#terraform-iac) - [5. CI/CD, GitOps (ArgoCD) & Progressive Delivery](#cicd-gitops) - [6. Frequently Asked DevOps Interview Questions](#devops-faqs) ## 1. Kubernetes Cluster Architecture & Control Plane Internals Kubernetes coordinates declarative state through a distributed control plane. Interviewers expect candidates to describe how an API request moves through each component. #### 1. kube-apiserver The only component that communicates with etcd. Validates, authenticates, and configures data for pod, service, replication controller objects. #### 2. etcd Consistent, highly-available key-value store using Raft consensus to persist cluster state. Requires an odd number of nodes (3 or 5) for quorum (N/2 + 1). #### 3. kube-scheduler Assigns unscheduled pods to worker nodes via two phases: *Filtering (Predicates)* to find eligible nodes, and *Scoring (Priorities)* to choose the best node. #### 4. kubelet Node agent ensuring containers described in PodSpecs are running and healthy via the Container Runtime Interface (CRI). ## 2. Troubleshooting Pods: CrashLoopBackOff, OOMKilled & Pending ### CrashLoopBackOff: Root Causes & Fixes Indicates a pod starts, fails, restarts, and crashes repeatedly with exponential backoff delay. ``` # Debugging step-by-step: kubectl describe pod -n kubectl logs --previous # Common causes: Application fatal exception, missing environment variable/ConfigMap, permission error. ``` ### OOMKilled (Exit Code 137) The container exceeded its configured memory limit and was terminated by the Linux kernel Out-Of-Memory killer. Fix: Increase `resources.limits.memory` or diagnose memory leaks in the app runtime. ## 3. Docker Multi-Stage Builds & Security Hardening Writing production-grade Dockerfiles requires minimizing image size and eliminating root privileges. ``` # Stage 1: Build stage with compiler tools FROM golang:1.24-alpine AS builder WORKDIR /app COPY go.mod go.sum ./ RUN go mod download COPY . . RUN CGO_ENABLED=0 GOOS=linux go build -o server . # Stage 2: Minimal runtime image without build bloat FROM alpine:3.20 RUN adduser -D -u 10001 appuser USER appuser COPY --from=builder /app/server /usr/local/bin/server EXPOSE 8080 ENTRYPOINT ["/usr/local/bin/server"] ``` ## 4. Terraform & Infrastructure as Code Best Practices Key questions asked about Terraform state management and security: - **Remote Backend & Locking:** Storing state in AWS S3 with encryption and using DynamoDB for state locking prevents concurrent executions from corrupting infrastructure state. - **Terraform Drift:** When physical cloud resources change outside Terraform. Detected with `terraform plan -refresh-only` and aligned with `terraform apply -refresh-only`. - **Terraform Modules:** Promote DRY (Don't Repeat Yourself) infrastructure patterns, enabling environment parity between Dev, Staging, and Production. ## 5. CI/CD, GitOps (ArgoCD) & Progressive Delivery Modern deployment pipelines rely on declarative Git repositories as the single source of truth: #### GitOps with ArgoCD & Flux ArgoCD runs inside the Kubernetes cluster and continuously monitors Git repos. If cluster state drifts from the committed manifests, it automatically reconciles or alerts engineers. #### Progressive Delivery & Automated Rollbacks Using Argo Rollouts or Flagger to automate Canary releases with Prometheus metrics analysis (HTTP error rates, p99 latency) triggers immediate automated rollbacks if thresholds are breached. ### Practice DevOps & SRE Technical Mock Interviews Simulate voice-based Kubernetes, CI/CD, and Linux troubleshooting interview panels with Sophia AI. Instant real-time feedback. [ Start Free DevOps Mock Interview ](/practice/devops-cloud-mock-interview) [ System Design Mock ](/practice/system-design-mock-interview) ## 6. Frequently Asked DevOps Interview Questions What is the difference between a Deployment and a StatefulSet in Kubernetes? A `Deployment` manages stateless application replicas with random pod names and shared storage, suitable for web servers. A `StatefulSet` provides unique, persistent ordinal pod identities (e.g., `kafka-0, kafka-1`), dedicated persistent volume claims per pod, and ordered startup/shutdown guarantees, essential for databases and distributed consensus nodes. What is the difference between Blue-Green and Canary deployments? In Blue-Green deployment, two identical production environments exist; 100% of live traffic flips instantaneously from Blue (old) to Green (new). In Canary deployment, new software is deployed alongside existing versions and receives a small percentage of user traffic (e.g., 5%) while metrics are analyzed before gradually scaling to 100%. --- ### Practice Live with Sophia AI Practice realistic voice technical interviews tailored directly to your real resume at https://ratemyinterview.online. Sophia AI speaks and listens via your microphone with sub-second speech latency (~900ms), giving instant objective scores, full transcripts, and question-by-question model solutions.