1. How would you set up a secure multi-region architecture in AWS?
Answer:
To set up a secure multi-region architecture, I would deploy resources in multiple regions using AWS VPCs and configure AWS Direct Connect or VPN for secure inter-region communication. I would also use AWS Route 53 for DNS-based routing across regions and AWS Global Accelerator to improve latency and fault tolerance. IAM roles and policies would be configured to restrict access to specific regions based on security requirements.
2. How do you automate the provisioning of resources in AWS using Infrastructure as Code (IaC)?
Answer:
I would use AWS CloudFormation or Terraform to define and provision infrastructure. CloudFormation templates or Terraform scripts would describe all the AWS resources, such as EC2 instances, RDS databases, and S3 buckets. Using version control, the IaC scripts can be stored and applied consistently across environments. For automated provisioning, I would integrate this with a CI/CD pipeline.
3. How would you configure auto-scaling for an EC2-based application in AWS?
Answer:
To configure auto-scaling, I would create an Auto Scaling Group (ASG) and configure scaling policies based on metrics like CPU utilization, memory usage, or custom CloudWatch metrics. The ASG would be linked to an Elastic Load Balancer (ELB) to distribute traffic across instances. The scaling policy would automatically launch new EC2 instances or terminate them when specific thresholds are reached.
4. How would you ensure high availability for a database in AWS?
Answer:
For high availability, I would use Amazon RDS Multi-AZ deployments, which automatically replicate the database to a standby instance in a different availability zone. This ensures automatic failover in case of a failure. For NoSQL databases, I would use Amazon DynamoDB with Global Tables to replicate data across multiple regions. Additionally, I would set up read replicas for scaling read operations.
5. How do you manage and secure sensitive data such as passwords in AWS?
Answer:
I would use AWS Secrets Manager or AWS Systems Manager Parameter Store to securely store sensitive data like API keys, database passwords, and other credentials. These services provide encryption at rest and can be easily accessed by applications using IAM roles. Additionally, I would implement IAM policies to restrict access to these secrets based on least-privilege principles.
6. How do you monitor and manage the cost of AWS resources?
Answer:
To monitor and manage costs, I would use AWS Cost Explorer and AWS Budgets to track and analyze spending patterns. I would also set up AWS CloudWatch to monitor usage and create alarms for threshold breaches. Using AWS Trusted Advisor, I would identify cost-saving opportunities such as unused resources, underutilized instances, and potential Reserved Instance purchases.
7. How would you configure an Amazon S3 bucket for cross-region replication?
Answer:
To configure cross-region replication (CRR), I would enable S3 replication on the source bucket and specify the destination region. I would also configure an IAM role with permissions to allow S3 to replicate objects. If needed, I would enable versioning on both the source and destination buckets to ensure all object versions are replicated.
8. How would you implement CI/CD pipelines in AWS using AWS CodePipeline?
Answer:
I would use AWS CodePipeline to create a CI/CD pipeline that integrates with AWS CodeCommit (for source control), AWS CodeBuild (for build automation), and AWS CodeDeploy (for deployment). The pipeline would trigger automatically when a change is pushed to CodeCommit, run unit tests in CodeBuild, and deploy the application to EC2 instances or Lambda functions.
9. How do you ensure secure access to AWS resources with IAM?
Answer:
I would use IAM roles to provide temporary credentials to services and users, adhering to the principle of least privilege. I would enforce MFA (Multi-Factor Authentication) for all users with access to the AWS console. Additionally, I would implement IAM policies to restrict access to specific resources, services, or actions. AWS Organizations can be used to centrally manage and apply policies across multiple accounts.
10. How would you use Amazon CloudWatch to monitor your application’s health?
Answer:
I would set up CloudWatch metrics for EC2 instances, RDS databases, Lambda functions, and other AWS resources to monitor their performance. I would configure CloudWatch Alarms to alert when a metric breaches a threshold, such as high CPU utilization or low disk space. I would also set up CloudWatch Logs to collect and analyze log data from EC2 instances and applications.
11. How do you ensure the security of EC2 instances in AWS?
Answer:
I would follow security best practices such as:
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Using Security Groups and Network ACLs to control inbound and outbound traffic to the EC2 instances.
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Ensuring that only required ports are open and using SSH keys for secure access.
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Installing and configuring AWS Systems Manager for patch management and security updates.
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Enabling CloudTrail to monitor API activity and implement IAM roles with the least privilege.
12. How would you secure a REST API hosted on AWS API Gateway?
Answer:
I would secure the API using AWS IAM roles and policies to restrict access to authorized users. Additionally, I would implement AWS WAF (Web Application Firewall) to protect against common web exploits and configure API keys or Cognito User Pools for user authentication. I could also integrate Lambda authorizers for custom authentication and authorization logic.
13. How do you handle logging and auditing in AWS?
Answer:
For logging, I would use AWS CloudTrail to capture all API calls and Amazon CloudWatch Logs to collect logs from EC2 instances, Lambda functions, and other AWS services. I would ensure that CloudTrail is enabled across all regions and integrate it with Amazon S3 for long-term storage. For auditing, I would periodically review the logs for unusual activity and integrate AWS Config to track changes to AWS resources.
14. How would you implement fault tolerance and disaster recovery in AWS?
Answer:
I would use AWS Multi-AZ deployments for critical services like RDS to ensure automatic failover in case of an AZ failure. For S3, I would enable cross-region replication to replicate data between regions. In addition, I would configure AWS Elastic Load Balancers and Auto Scaling Groups to ensure the application is highly available and can recover from instance failures.
15. How would you automate the deployment of infrastructure using AWS CloudFormation?
Answer:
In AWS CloudFormation, I would define resources such as VPCs, EC2 instances, S3 buckets, and RDS databases in a CloudFormation template (YAML or JSON). This template would be version-controlled and deployed automatically through CI/CD pipelines using AWS CodePipeline or Jenkins. I would also use CloudFormation StackSets to deploy resources across multiple regions or accounts.
16. How do you configure VPC peering between two VPCs in different AWS accounts?
Answer:
To configure VPC peering, I would create a peering connection request from one VPC and accept the request in the other VPC. I would update the route tables in both VPCs to route traffic to the peered VPC. Additionally, I would modify Security Groups and Network ACLs to allow communication between instances in the two VPCs.
17. How do you handle session management and scaling for a web application in AWS?
Answer:
I would use Amazon Elastic Load Balancer (ELB) to distribute traffic across multiple EC2 instances, ensuring high availability. For session management, I would store session data in Amazon DynamoDB or Amazon ElastiCache to ensure sessions are maintained across multiple instances. Additionally, I would enable Auto Scaling to automatically scale the instances based on traffic.
18. How would you use Amazon S3 for data archiving and long-term storage?
Answer:
I would configure S3 buckets with versioning to retain multiple versions of objects. To lower storage costs, I would use S3 Lifecycle Policies to automatically move data to S3 Glacier or S3 Glacier Deep Archive for long-term storage. Additionally, I would configure S3 Object Locking to prevent accidental deletion of archived data.
19. How do you set up cross-account access in AWS using IAM roles?
Answer:
To set up cross-account access, I would create an IAM role in the target account with the necessary permissions. In the source account, I would create an IAM policy allowing users or services to assume the role in the target account using the sts:AssumeRole action. The user or service in the source account would use AWS CLI or SDKs to assume the role.
20. How do you scale an Amazon RDS database to handle increased traffic?
Answer:
I would use Amazon RDS Read Replicas to offload read traffic from the primary database. Additionally, I would use Amazon RDS Multi-AZ deployments for automatic failover and high availability. If more storage is needed, I would resize the RDS instance to a larger type or scale horizontally by adding more read replicas.