DBS-C01 Workload-Specific Database Design Practice Question
Exhibit
Consider the following IAM policy attached to an RDS DB instance:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "rds-db:connect",
"Resource": "arn:aws:rds-db:us-east-1:123456789012:dbuser:db-ABCDEFGHIJKL01234/db_user1"
}
]
}Refer to the exhibit. A database specialist is troubleshooting an issue where an application cannot connect to an RDS for MySQL instance using IAM database authentication. The application uses the database user 'db_user1'. The IAM policy shown is attached to the IAM role used by the application. What is the most likely reason for the connection failure?
⚠ Common exam trap
A common mix-up: candidates confuse the DB instance name or endpoint with the RDS resource ID, or assume the database user must be 'admin' for IAM authentication, when in fact the resource ID is a separate identifier and the user name must match the database user exactly.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The resource ARN in the policy uses an incorrect RDS resource ID.
IAM database authentication for RDS MySQL requires the resource ARN in the IAM policy to include the correct RDS resource ID (the 'db-xxxxx' identifier from the RDS console), not the DB instance name or endpoint. If the ARN uses an incorrect resource ID, the policy will not match the target RDS instance, causing the authentication to fail even if the user name and action are correct.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The action 'rds-db:connect' is not allowed for RDS MySQL.
Why it's wrong here
The action is correct for IAM database authentication.
- ✗
The policy should have 'Deny' effect instead of 'Allow'.
Why it's wrong here
Allow is correct for granting access.
- ✓
The resource ARN in the policy uses an incorrect RDS resource ID.
Why this is correct
The RDS resource ID must be exactly 14 alphanumeric characters. The example has 18.
- ✗
The database user name in the ARN must be 'admin', not 'db_user1'.
Why it's wrong here
The user name should match the database user.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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