AWS Question EP6

• AWS Certified Solutions Architect Associate

• RDS & DynamoDB

You are working as a Cloud Architect in a big IT Firm. To ensure high availability of both the web servers and your web application database, you deployed your auto-scaled EC2 instances in multiple Availability Zones with an Application Load Balancer in front. You configured Multi-Availability Zone to your RDS instance. There is a spike in incoming requests in the past few hours, and the performance of the primary database is starting to go down. What would happen to the database if the primary DB instance fails?

• A. The IP address of the primary DB instance is switched to the standby DB instance.

• B. The RDS DB instance will automatically reboot.

• C. A new DB instance will be created and immediately replace the primary database.

• D. The canonical name record will be changed from the primary database to the standby database.

Answer explanation

Answer: D

• Option A is incorrect because IP Address is associated with A Records in DNS, but for Database, you need to change the CNAME record.

• Option B is incorrect because RDS Instance is pointed to standby RDS.

• Option C  is incorrect because this option is not reliable in real-time.

• Option D is correct because the failover mechanism automatically changes the DNS CNAME record of the DB instance to point to the standby DB instance.

• AWS Certified Solutions Architect Associate

• RDS & DynamoDB

A company is planning to migrate an on-premise 15 TB MySQL database cluster onto AWS. The replication lag needs to be less than 100 ms for the cluster, and the size is expected to double in the next couple of months. Which of the following would be the ideal data store that should be chosen in AWS?

• A. AWS RDS MySQL

• B. AWS Aurora

• C. AWS DynamoDB

• D. AWS Redshift

Answer explanation

Answer: B

• Option B is correct because all Aurora Replicas return query results with minimal replica lag—usually much less than 100 milliseconds after the primary instance has written an update. For Scaling, this is the best among all the options. The minimum storage is for AWS Aurora is 10GB. Based on your database usage, your Amazon Aurora storage will automatically grow, up to 128 TB, in 10GB increments with no impact on database performance. There is no need to provision storage in advance. Amazon Aurora is a compatible MySQL database that can take on tremendous growth in terms of data size.

• AWS Certified Solutions Architect Associate

• RDS & DynamoDB

You are working as an AWS Architect for a multinational bank with hybrid cloud architecture. The bank is running a currency exchange website that uses a MySQL Server RDS instance as its database. As part of the company's business continuity plan, there is a need to keep a read replica of the production RDS instance to the bank's on-premise data center. In this scenario, what is the most secure and effective way to meet this requirement?

• A. Change the MySQL Server RDS instance as the master node and then enable replication over the public Internet using a secure SSL endpoint to a server on the on-premise data center.

• B. Configure the MySQL Server RDS instance to replicate to an EC2 instance with core MySQL and then enable Replication over a secure VPN connection.

• C. Use native backup and restore for MySQL Server databases using full backup files by storing it on Amazon S3, and then restore the backup file onto an on-premises server.

• D. Create an IPsec VPN connection from AWS to the On-Premise datacenter through the Virtual Private Cloud service and configure replication in MySQL Server.

Answer explanation

Answer: D

• Option A is incorrect as it is feasible. You could put your RDS DB in a public subnet and configure SSL for it. But you have been asked for the most secure way.

• Option B is incorrect because Even EC2 is external to RDS, and it won’t be a secure option.

• Option C is incorrect because it describes a backup-restore solution.

• Option D is correct because it provides the most secure direct connection from the RDS MySQL Server instance to the On-Premise data center, and replication can be configured within the MySQL Server service since it can't be done from the RDS service to the On-Premise data center.

• AWS Certified Solutions Architect Associate

• RDS & DynamoDB

Your team has developed an online feedback application for the best image competition in AWS using CloudFormation. The application accepts high-quality images of each participant and stores them in S3. Then it records the information about the image as well as the participant’s profile in RDS. After the competition, the CloudFormation stack is not used anymore and should be terminated to save the cost. Your manager instructed you to back up the RDS database and the S3 bucket so the data can still be used even after the CloudFormation template is deleted. Which of the following options will fulfill this requirement?

• A. Set the DeletionPolicy for the RDS instance to snapshot and then enable S3 bucket replication on the source bucket to a destination bucket to maintain a copy of all the S3 objects.

• B. Set the DeletionPolicy to retain on both the RDS and S3 resource types on the CloudFormation template.

• C. Set the DeletionPolicy on the S3 bucket to snapshot

• D. Set the DeletionPolicy on the RDS resource to snapshot and set the S3 bucket to retain.

Answer explanation

Answer: D

• Option A is incorrect because a replica of the S3 bucket is not required. We can directly retain it.

• Option B is incorrect because for RDS the DeletionPolicy should be Snapshot and for S3 it should be Retain.

• Option C is incorrect because RDS also needs to be backed up.

• Option D is correct because the Retain option keeps the resource in the event of a stack deletion. The Snapshot option creates a snapshot of the resource before that resource is deleted. The Delete option deletes the resource along with the stack.

• AWS Certified Solutions Architect Associate

• RDS & DynamoDB

You are working as a Cloud Engineer for a startup company that is planning to develop a web application with a ReactJS frontend in EC2 and DynamoDB with provisioned throughput (1000 Writes/Sec) as its database. They are expecting a high number of writes on the database during peak hours (3000 Writes/Sec). How could you ensure the scalability and cost-effectiveness of the application to reduce the load on the DynamoDB database?

• A. Add more DynamoDB databases to handle the load.

• B. Use DynamoDB Auto Scaling.

• C. Increase write capacity of DynamoDB to meet the peak loads.

• D. Configure an Application Load Balancer in front of the EC2 Auto Scaling group.

Answer explanation

Answer - B

• Option A is incorrect because this option is neither Cost-effective nor reliable.

• Option B is correct because if your application can handle some throttling from DynamoDB when there’s a sudden increase in traffic, you should use DynamoDB Auto Scaling.

• Option C is incorrect because you have to do the same thing manually again and again in the future.

• Option D is incorrect this option does not help to reduce the load on the DynamoDB. When there are a high number of writes on the database, we should adjust the write throughput by DynamoDB Auto Scaling.