Amazon Web Services Updated SAA-C03 Exam Questions and Answers by aaryan

This option is the most efficient because it uses provisioned mode, which is a read/write capacity mode for processing reads and writes on your tables that lets you specify how much read and write throughput you expect your application to perform1. It also specifies the read capacity units (RCUs) and write capacity units (WCUs), which are the amount of data your application needs to read or write per second. It also meets the requirement of staying at or below its forecasted budget for DynamoDB, as provisioned mode has lower costs than on-demand mode for predictable workloads. This solution meets the requirement of collecting data from a large number of participants who use wearable devices with a constant and predictable data workload. Option A is less efficient because it uses provisioned mode and DynamoDB Standard-Infrequent Access (DynamoDB Standard-IA), which is a storage class for infrequently accessed items that require milliseconds latency2. However, this does not meet the requirement of collecting data from a large number of participants who use wearable devices with a constant and predictable data workload, as DynamoDB Standard-IA is more suitable for items that are accessed less frequently than once every 30 days. Option C is less efficient because it uses on-demand mode, which is a read/write capacity mode that lets you pay only for what you use by automatically adjusting your table’s capacity in response to changing demand3. However, this does not meet the requirement of staying at or below its forecasted budget for DynamoDB, as on-demand mode has higher costs than provisioned mode for predictable workloads. Option D is less efficient because it uses on-demand mode and specifies the RCUs and WCUs with reserved capacity, which is a way to reserve read and write capacity for your tables in exchange for discounted hourly rates. However, this does not meet the requirement of staying at or below its forecasted budget for DynamoDB, as on-demand mode has higher costs than provisioned mode for predictable workloads. Also, specifying RCUs and WCUs with reserved capacity is not possible with on-demand mode, as it only applies to provisioned mode.

Creating a peering connection between the two VPCs and configuring an inbound rule for the ElastiCache cluster's security group to allow inbound connection from the application's security group is the most cost-effective solution. Peering connections are free and you only incur the cost of configuring the security group rules. The Transit VPC solution requires additional VPCs and associated resources, which would incur additional costs.

Before Testing | AWS Certification Information and Policies | AWS

https://aws.amazon.com/certification/policies/before-testing/

This option is the most efficient because it uses a gateway VPC endpoint for Amazon S3, which provides reliable connectivity to Amazon S3 without requiring an internet gateway or a NAT device for the VPC1. A gateway VPC endpoint routes traffic from the VPC to Amazon S3 using a prefix list for the service and does not leave the AWS network2. This meets the requirement of not traversing the internet. Option A is less efficient because it uses a private hosted zone by using Amazon Route 53, which is a DNS service that allows you to create custom domain names for your resources within your VPC3. However, this does not provide connectivity to Amazon S3 without an internet gateway or a NAT device. Option C is less efficient because it uses a NAT gateway to access the S3 bucket, which is a highly available, managed Network Address Translation (NAT) service that enables instances in a private subnet to connect to the internet or other AWS services, but prevents the internet from initiating a connection with those instances4. However, this does not meet the requirement of not traversing the internet. Option D is less efficient because it uses an AWS Site-to-Site VPN connection between the VPC and the S3 bucket, which is a secure and encrypted network connection between your on-premises network and your VPC. However, this does not meet the requirement of not traversing the internet.

 Security groups are virtual firewalls that protect AWS instances and can be applied to EC2, ELB and RDS1. Security groups have rules for inbound and outbound traffic and are stateful, meaning that responses to allowed inbound traffic are allowed to flow out of the instance2. Network ACLs are different from security groups in several ways. They cover entire subnets, not individual instances, and are stateless, meaning that they require rules for both inbound and outbound traffic2. Network ACLs also support deny rules, while security groups only support allow rules2.

To meet the requirements of the scenario, the solutions architect should create two security groups: one for the DB instance and one for the web servers in the public subnet. The security group for the DB instance should allow traffic from the public subnet CIDR block on port 3306, which is the default port for MySQL3. This way, only the web servers in the public subnet can access the DB instance on that port. The security group for the web servers should allow traffic from 0 0 0 O’O on port 443, which is the default port for HTTPS4. This way, the web servers can accept secure connections from the internet on that port.