What is the Twelve-Factor App methodology?

The Twelve-Factor App is a set of best practices for building modern, scalable cloud applications. The 12 principles focus on aspects like codebase, dependencies, configuration, logging, and disposability.

How do you implement zero-trust security in DevOps?

Zero-trust security enforces strict identity verification and least-privilege access across the entire system. It includes:

• Multi-factor authentication (MFA)
• Role-Based Access Control (RBAC)
• Encryption of data in transit and at rest
• Continuous monitoring and logging

What are sidecars in Kubernetes?

A sidecar is a helper container that runs alongside a main application container within the same pod. Sidecars enhance functionality without modifying the primary application (e.g., logging, monitoring, service mesh).

How does Kubernetes handle self-healing?

Kubernetes ensures self-healing by:

• Restarting failed containers
• Rescheduling pods on healthy nodes
• Automatically scaling replicas
• Rolling back deployments if necessary

What is progressive delivery?

Progressive delivery is an advanced deployment strategy that introduces new changes incrementally to users, using techniques like:

• Canary releases (small group testing)
• Feature flags (turning features on/off dynamically)
• A/B testing (comparing multiple versions in production)

What is a service mesh, and why is it important?

A service mesh (e.g., Istio, Linkerd) is a dedicated infrastructure layer that manages service-to-service communication in microservices architectures. It provides:

• Traffic control (load balancing, retries)
• Security (mutual TLS authentication)
• Observability (tracing, metrics, logging)

What is GitOps, and how does it improve DevOps workflows?

GitOps uses Git repositories as the single source of truth for declarative infrastructure and applications. Benefits include:

• Version-controlled deployments
• Automated reconciliation of state
• Increased security via RBAC

What is Blue/Green vs. Rolling deployment?

• Blue/Green Deployment: Two identical environments (Blue and Green). Traffic is switched instantly.
• Rolling Deployment: Gradual update of application instances, minimizing downtime but increasing rollback complexity.

How do you handle secrets management in DevOps?

Best practices for secrets management include:

• Using vault solutions (e.g., HashiCorp Vault, AWS Secrets Manager)
• Avoiding hardcoded secrets in code
• Using environment variables or encrypted configuration files

What is a chaos engineering experiment?

Chaos engineering involves intentionally introducing failures to test system resilience. Examples include:

• Network disruptions (latency, packet loss)
• Server crashes (killing pods or nodes)
• Resource exhaustion (CPU/memory spikes)

How do you implement compliance in DevOps pipelines?

Compliance can be enforced using:

• Automated security scans (e.g., SonarQube, Snyk)
• Policy-as-Code (e.g., Open Policy Agent)
• Audit logging and access controls

What is infrastructure drift, and how do you prevent it?

Infrastructure drift occurs when real-world infrastructure deviates from its declared state in code. Prevention methods:

• Use Infrastructure as Code (IaC) tools
• Regularly run drift detection checks
• Automate infrastructure provisioning

What is a deployment freeze, and when should it be used?

A deployment freeze is a temporary halt on new releases, typically during critical business periods (e.g., holiday sales, tax season).

How do you ensure high availability in a DevOps environment?

High availability can be ensured through:

• Multi-region deployments
• Load balancing & auto-scaling
• Database replication & failover mechanisms

What is a multi-cloud strategy?

A multi-cloud strategy uses multiple cloud providers (e.g., AWS, Azure, GCP) to:

• Reduce vendor lock-in
• Improve redundancy and fault tolerance
• Optimize costs

How does FinOps fit into DevOps?

FinOps (Financial Operations) helps manage cloud spending efficiently. Practices include:

• Cost monitoring tools (AWS Cost Explorer, Azure Cost Management)
• Auto-scaling and right-sizing resources
• Tagging and budgeting policies

What are the challenges of DevOps adoption in large enterprises?

• Legacy system integration
• Security and compliance concerns
• Cultural resistance to automation
• Skill gaps within teams

What is a Kubernetes operator?

A Kubernetes Operator automates complex application lifecycle management tasks by extending Kubernetes capabilities using custom controllers.

What are observability pillars in DevOps?

The three pillars of observability are:

• Logs (text-based records of system events)
• Metrics (numerical measurements like CPU usage)
• Tracing (tracking requests across distributed systems)

What are the best practices for incident response in DevOps?

• Automated alerts and monitoring (PagerDuty, Prometheus)
• Runbooks and playbooks for issue resolution
• Post-mortems for continuous learning