Here you have the best Amazon AWS Certified Database - Specialty practice exam questions
A company has deployed an e-commerce web application in a new AWS account. An Amazon RDS for MySQL Multi-AZ DB instance is part of this deployment with a database-1.xxxxxxxxxxxx.us-east-1.rds.amazonaws.com endpoint listening on port 3306. The company's Database Specialist is able to log in to MySQL and run queries from the bastion host using these details.
When users try to utilize the application hosted in the AWS account, they are presented with a generic error message. The application servers are logging a `could not connect to server: Connection times out` error message to Amazon CloudWatch Logs.
What is the cause of this error?
The error message 'could not connect to server: Connection times out' commonly indicates an issue with network connectivity or firewalls. In the context of AWS, security groups act as virtual firewalls to control inbound and outbound traffic to instances. Since the application servers cannot connect to the database, it is likely that the security group associated with the DB instance does not have a rule allowing inbound connections on the MySQL default port (3306) from the application servers. Ensuring the correct security group rules are in place would resolve this connectivity issue.
An AWS CloudFormation stack that included an Amazon RDS DB instance was accidentally deleted and recent data was lost. A Database Specialist needs to add
RDS settings to the CloudFormation template to reduce the chance of accidental instance data loss in the future.
Which settings will meet this requirement? (Choose three.)
To prevent accidental data loss of an Amazon RDS DB instance in an AWS CloudFormation stack, certain settings need to be configured. Setting DeletionProtection to True ensures that the RDS instance cannot be deleted accidentally. Setting DeleteAutomatedBackups to False prevents the deletion of automated backups, thus aiding in data recovery in case of accidental deletion. Setting DeletionPolicy to Retain ensures that the resources are retained even if the CloudFormation stack is deleted, rather than being deleted themselves. These measures collectively help in safeguarding against accidental data loss.
A Database Specialist is troubleshooting an application connection failure on an Amazon Aurora DB cluster with multiple Aurora Replicas that had been running with no issues for the past 2 months. The connection failure lasted for 5 minutes and corrected itself after that. The Database Specialist reviewed the Amazon
RDS events and determined a failover event occurred at that time. The failover process took around 15 seconds to complete.
What is the MOST likely cause of the 5-minute connection outage?
The 5-minute connection outage is most likely caused by the client-side application caching the DNS data with a time-to-live (TTL) set too high. After a failover, the underlying IP address of a DB instance can change. If the application continues to use a cached DNS entry with the old IP address, it will fail to connect to the new instance. Setting a shorter TTL for the DNS cache would ensure that the client application updates its DNS information quickly after a failover.
A company is deploying a solution in Amazon Aurora by migrating from an on-premises system. The IT department has established an AWS Direct Connect link from the company's data center. The company's Database Specialist has selected the option to require SSL/TLS for connectivity to prevent plaintext data from being set over the network. The migration appears to be working successfully, and the data can be queried from a desktop machine.
Two Data Analysts have been asked to query and validate the data in the new Aurora DB cluster. Both Analysts are unable to connect to Aurora. Their user names and passwords have been verified as valid and the Database Specialist can connect to the DB cluster using their accounts. The Database Specialist also verified that the security group configuration allows network from all corporate IP addresses.
What should the Database Specialist do to correct the Data Analysts' inability to connect?
The Data Analysts are unable to connect to the Aurora DB cluster likely because the connection requires SSL/TLS and they have not configured their connections to use the SSL certificate. To connect using SSL/TLS, the Analysts need to download the root certificate provided by AWS and include it in their connection string. This ensures that the connection is secure, as required by the Database Specialist's settings. Restarting the DB cluster, modifying firewalls, or adding IP address mappings wouldn't address this SSL requirement directly.
A company is concerned about the cost of a large-scale, transactional application using Amazon DynamoDB that only needs to store data for 2 days before it is deleted. In looking at the tables, a Database Specialist notices that much of the data is months old, and goes back to when the application was first deployed.
What can the Database Specialist do to reduce the overall cost?
To reduce the overall cost, the Database Specialist should create a new attribute in each table to track the expiration time and enable time to live (TTL) on each table. TTL automatically deletes expired items from the table without requiring manual intervention, effectively managing storage costs by ensuring that only necessary data is retained. Unlike complex solutions involving AWS Glue transformations or data pipelines, TTL is a native feature of DynamoDB designed specifically for this purpose and does not incur additional costs.