RDS (Relational Database Service) quiz · Level 0

Question 1What does Amazon RDS do for Todo.io that running MySQL on its own EC2 instance would not?

AWS installs, patches and backs up the database for you.Correct. You still design tables and write SQL; RDS runs the database server.It removes the need for SQL.Not this one. RDS runs ordinary engines like MySQL and PostgreSQL; you still use SQL.It removes the need for security groups.Not this one. RDS runs in your VPC, and security groups still decide who can connect.It turns the database into HTTPS API calls with no connections.Not this one. That describes DynamoDB. With RDS you open normal database connections.

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Question 2Todo.io's app can't connect to its RDS MySQL database: the connection times out. The password is correct. What is the most likely cause?

The database's security group doesn't allow inbound TCP 3306 from the app.Correct. A silent timeout is what a security group does with traffic it doesn't allow.The app's IAM role lacks permission to run SQL.Not this one. Connections to MySQL on RDS use a database username and password, and a wrong one is refused, not timed out.CloudTrail is blocking the connection.Not this one. CloudTrail only records; it never blocks.The database needs a public IP.Not this one. The app is in the same VPC and uses the private IP.

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Question 3In Todo.io's Level 0 setup, how does the app prove who it is to its RDS MySQL database?

With a database username and password, over a normal connection on port 3306.Correct. RDS is connected to like any MySQL server. Keeping that password out of code is a Level 1 topic.Every SQL query is an HTTPS call signed with IAM, like DynamoDB.Not this one. That is how DynamoDB works, not MySQL.It doesn't; anything inside the VPC may connect.Not this one. The security group decides who may reach it, and the database still checks credentials.With the root user's access keys.Not this one. Root keys should never exist, and MySQL doesn't use them.

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Question 4Todo.io is creating a single-AZ RDS database, but its DB subnet group must include subnets in at least two Availability Zones. Why?

So a standby in another Availability Zone can be added later without rebuilding.Correct. RDS insists on two AZs up front, even if you only use one today.Because the data is split across both AZs.Not this one. A single-AZ database keeps its data in one AZ.Because it is cheaper.Not this one. The subnet group costs nothing either way.So the database gets a public IP.Not this one. Public access is a separate setting, and a bad idea here.

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Question 5Someone ran DELETE FROM todos on Todo.io's RDS database. Will CloudTrail show who did it?

No. CloudTrail records AWS API calls, not the SQL run inside a database. The database's own logs would show it.Correct. CloudTrail would show CreateDBInstance or DeleteDBInstance, never what happens inside.Yes. CloudTrail records every SQL statement.Not this one. It never sees inside the database.Yes, but only with AWS Config turned on.Not this one. Config records resource settings, not queries.Yes, in CloudWatch metrics.Not this one. Metrics are numbers, such as connections or CPU, not who ran what.

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Question 6Todo.io needs reports that join users, todos and tags with SQL. Which service fits?

Amazon RDS, a relational database.Correct. Joins across related tables are what relational databases are built for.Amazon DynamoDB.Not this one. DynamoDB finds items by key and has no SQL joins.Amazon S3.Not this one. S3 stores files, not related tables.Amazon SQS.Not this one. SQS holds messages waiting to be processed.

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Question 7Unlike DynamoDB, where does an Amazon RDS database run?

Inside your VPC, in your subnets, with security groups deciding who can connect.Correct. DynamoDB is reached through a public AWS endpoint instead.Outside the VPC, behind a public AWS endpoint.Not this one. That describes DynamoDB.Only in your own data centre.Not this one. RDS runs in AWS.Inside the Lambda function that uses it.Not this one. Databases run on their own; functions connect to them.

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Question 8What does "RDS (Relational Database Service)" mean?

A managed SQL database, like MySQL or PostgreSQL, that AWS runs for you.Correct. Think of it as: A filing cabinet with a librarian AWS employs.A fully managed NoSQL database you use through AWS API calls.Not this one. That describes DynamoDB.Unlimited storage for files ("objects") in containers called buckets.Not this one. That describes S3 (Simple Storage Service).The permission to hand an existing role to an AWS service.Not this one. That describes iam:PassRole.

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Question 9Which term is this? "A managed SQL database, like MySQL or PostgreSQL, that AWS runs for you."

RDS (Relational Database Service)Correct. Yes. Think of it as: A filing cabinet with a librarian AWS employs.DynamoDBNot this one. DynamoDB is: A fully managed NoSQL database you use through AWS API calls.S3 (Simple Storage Service)Not this one. S3 (Simple Storage Service) is: Unlimited storage for files ("objects") in containers called buckets.iam:PassRoleNot this one. iam:PassRole is: The permission to hand an existing role to an AWS service.

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Question 10Which AWS term is described by this analogy? "A filing cabinet with a librarian AWS employs."

RDS (Relational Database Service)Correct. Yes: A managed SQL database, like MySQL or PostgreSQL, that AWS runs for you.DynamoDBNot this one. DynamoDB is: A fully managed NoSQL database you use through AWS API calls. Its analogy: A giant labelled locker wall where you fetch lockers by their exact key.S3 (Simple Storage Service)Not this one. S3 (Simple Storage Service) is: Unlimited storage for files ("objects") in containers called buckets. Its analogy: A warehouse of labelled boxes you can reach from anywhere.iam:PassRoleNot this one. iam:PassRole is: The permission to hand an existing role to an AWS service. Its analogy: Being allowed to lend your colleague's key card to a contractor.

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