Amazon SOA-C03 Exam Questions

For Amazon RDS for MySQL, a Multi-AZ DB instance deployment provides synchronous standby replication to another Availability Zone and supports automatic failover if the primary DB instance or Availability Zone fails. This directly meets the requirement for failover while minimizing application downtime. A read replica in the same Availability Zone does not provide the same automatic high-availability failover path and is mainly used for read scaling. Auto Scaling groups apply to EC2 instances, not RDS DB instances. RDS Proxy can improve application connection handling and failover behavior, but it does not by itself create a standby database for a Single-AZ instance. The database must first have a high-availability deployment. Therefore, modifying the DB instance to Multi-AZ is the correct reliability solution.

The PrivateDnsName attribute of an EC2 instance is automatically assigned by AWS at launch time and is a read-only property. CloudFormation does not allow users to specify this value manually.

Including PrivateDnsName in the EC2 instance properties causes validation to fail during stack creation. Outputs and Parameters sections are optional, and the VPC is implicitly defined through the subnet ID.

Therefore, attempting to set PrivateDnsName results in stack creation failure.

Cluster placement groups are specifically designed for workloads that require extremely low latency and high network throughput, such as HPC applications. Instances are placed physically close together within the same Availability Zone, enabling high-bandwidth, low-latency networking.

Partition placement groups are optimized for fault isolation, not network performance. Spread placement groups prioritize availability by distributing instances across distinct hardware, which increases latency.

Because the requirement is performance rather than fault isolation or high availability, a cluster placement group is the optimal choice.

According to the AWS Cloud Operations and Identity Management documentation, when configuring federation between IAM Identity Center (formerly AWS SSO) and an external SAML 2.0 identity provider, two key prerequisites are required:

The IAM Identity Center SAML metadata file --- This is uploaded to the external IdP to establish trust, define SAML endpoints, and enable identity federation.

The IdP metadata (including the public X.509 certificate) --- This information is imported into IAM Identity Center to validate authentication assertions and encryption signatures.

IAM Identity Center and the IdP exchange this metadata to mutually establish secure, bidirectional federation.

Network-level details such as IP addresses (Option C) are unnecessary. Root access (Option D) or permissions to member accounts (Option E) are not required; only Control Tower or IAM administrative permissions in the management account are needed for setup.

Thus, the correct answer is A and B --- the SAML metadata from both sides is required for federation.

By default, when AWS CloudFormation encounters a failure during stack creation, it automatically rolls back and deletes any resources that were successfully created. This behavior makes troubleshooting difficult because the failed and partially created resources are no longer available for inspection.

CloudFormation provides the OnFailure parameter to control this behavior. Setting the parameter to DO_NOTHING instructs CloudFormation to stop stack creation when a failure occurs and retain all successfully created resources. This allows the CloudOps engineer to inspect the environment, review logs, and identify the root cause without redeploying resources.

The DisableRollback parameter controls rollback behavior but does not provide the same explicit behavior control during failure scenarios. Rollback triggers are used for monitoring-based rollback, not for preserving resources on failure. Setting OnFailure to ROLLBACK explicitly enforces deletion, which is the opposite of the requirement.

Therefore, setting the OnFailure parameter to DO_NOTHING is the correct solution.