21 DevOps Interview Scenarios: Build a Secure, Scalable Cloud Project with AWS, Terraform, Docker & Kubernetes

In today’s cloud-driven world, building a secure, scalable, and fault-tolerant infrastructure is critical for businesses of all sizes. This guide walks through a real-world project that integrates AWS services, Terraform, Docker, Kubernetes, and CI/CD pipelines, while addressing key security, disaster recovery, and operational best practices. Each section answers a critical question, with detailed examples and corrections based on industry standards.

1. AWS Services & Security Best Practices

Key Services Used

1. Amazon EC2:
   • Security Groups: Act as virtual firewalls to control inbound/outbound traffic.
   • Key Management: Use AWS KMS to encrypt EBS volumes and instance storage.
2. Amazon S3:
   • Bucket Policies: Restrict access using IAM roles, IP whitelisting, and encryption (SSE-S3 or SSE-KMS).
   • Example policy with IP restriction:

     {
       "Version": "2012-10-17",
       "Statement": [
         {
           "Effect": "Allow",
           "Principal": { "AWS": "arn:aws:iam::123456789012:user/ExampleUser" },
           "Action": "s3:GetObject",
           "Resource": "arn:aws:s3:::example-bucket/*",
           "Condition": { "IpAddress": { "aws:SourceIp": "192.0.2.0/24" } }
         }
       ]
     }
     

3. AWS IAM:
   • Enforce least privilege access and enable MFA for root and privileged users.
4. AWS Shield & WAF:
   • Protect against DDoS attacks and malicious traffic.
5. AWS Config:
• Audit resource configurations for compliance.

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