Explain the difference between Docker and Kubernetes.

What is Blue-Green Deployment?

A strategy where two environments (Blue & Green) exist:

• Blue – Active
• Green – Staging (new version)
  Switching traffic to Green reduces downtime.

How does Terraform differ from Ansible?

• Terraform: Declarative, cloud provisioning
• Ansible: Configuration management, procedural

What is Canary Deployment?

A small subset of users receives the new update before a full rollout.

What are Helm charts in Kubernetes?

Helm automates Kubernetes app deployment using predefined templates.

What is a rolling update in Kubernetes?

A rolling update gradually replaces old pods with new ones without downtime.

How do you handle secrets securely in a DevOps pipeline?

1. HashiCorp Vault
2. AWS Secrets Manager
3. Kubernetes Secrets

What is an immutable infrastructure?

Infrastructure where components are never modified after deployment, reducing configuration drift.

What are the different types of Kubernetes services?

1. ClusterIP – Internal communication
2. NodePort – Exposes a service on a port
3. LoadBalancer – External traffic balancing

How does Prometheus monitor Kubernetes clusters?

• Uses exporters to collect metrics
• Stores time-series data
• Alerts on anomalies via Alertmanager

What is the difference between monolithic and microservices architectures?

How does Ansible differ from Chef and Puppet?

• Ansible – Agentless, YAML-based, simple
• Chef/Puppet – Require agents, more complex

How do you ensure high availability in a cloud environment?

1. Multi-AZ Deployments
2. Load Balancing
3. Auto Scaling

How do you handle stateful applications in Kubernetes?

Using StatefulSets, Persistent Volumes, and Storage Classes.

What is a sidecar container pattern in Kubernetes?

A sidecar runs alongside the main app container to handle logging, monitoring, or proxying.

How do you implement security in a CI/CD pipeline?

1. Static Code Analysis (SAST)
2. Container Scanning
3. Dependency Scanning

What is the concept of "Shift Left" in DevOps security?

"Shift Left" integrates security earlier in the development cycle, reducing vulnerabilities.

What is a Kubernetes DaemonSet?

A DaemonSet ensures that a pod runs on every node.

What is the difference between proactive and reactive monitoring?

• Proactive – Prevents issues (threshold-based alerts)
• Reactive – Responds to issues (post-failure logs)

What is the role of service mesh in Kubernetes?

A service mesh (e.g., Istio) manages service-to-service communication, security, and monitoring.