Monitoring your resources and ensuring your application can scale automatically are key to a resilient cloud architecture. Module 10 of the AWS Academy Cloud Architecting curriculum focuses on these areas.
Here is your comprehensive guide to the Module 10 Knowledge Check, including all questions, options, and the reasoning behind each answer.
1. Accuracy of Amazon EC2 Auto Scaling
Question: Which statement about Amazon EC2 Auto Scaling is accurate?
- Options:
- It can launch new Amazon EC2 instances based on a schedule.
- It can launch Amazon EC2 instances in multiple Availability Zones.
- It requires the customer to use Reserved Instances only.
- It can launch Amazon EC2 instances, but customers must terminate instances after they are no longer needed.
- Correct Answer: It can launch Amazon EC2 instances in multiple Availability Zones.
- Why: Amazon EC2 Auto Scaling can launch instances in multiple Availability Zones, which increases overall reliability for an implementation. This ensures that even if one Availability Zone experiences an outage, your application can remain operational in others.
2. Appropriate Scaling for Weekend Demand
Question: A devops engineer detected that the demand on a fleet of Amazon EC2 instances in an Auto Scaling group increases by a set amount on weekend days. Which type of scaling is the MOST appropriate in this case?
- Options:
- Scheduled
- Predictive
- Manual
- Dynamic
- Correct Answer: Scheduled
- Why: Scheduled scaling is most appropriate when there is a well-established pattern of demand, such as increased traffic on specific days like weekends. You can set up Amazon EC2 Auto Scaling to launch or terminate instances at specific times to meet these known changes in load.
3. CPU Utilization and Scaling
Question: A devops engineer launches a fleet of Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer. The EC2 instances must maintain 50 percent average CPU utilization. Which type of scaling is appropriate to use based on CPU utilization usage?
- Options:
- Step scaling
- Manual scaling
- Target tracking scaling
- Simple scaling
- Correct Answer: Target tracking scaling
- Why: Target tracking scaling provides the average CPU utilization as a standard target metric. A user can specify the target value (like 50 percent) and let Amazon EC2 Auto Scaling handle the rest by adding or removing instances to keep the metric as close to the target as possible.
4. Vertically Scaling an Amazon RDS Database
Question: How can a user vertically scale an Amazon RDS database?
- Options:
- By changing the instance class or size
- By creating dedicated read and write nodes
- By sharding the database
- By adding read replicas
- Correct Answer: By changing the instance class or size
- Why: Changing to instance types with greater capacity is an example of vertical scaling. This increases the resources (like CPU or memory) available to a single instance.
5. Horizontally Scaling an Amazon Aurora Database
Question: How can an AWS customer horizontally scale an Amazon Aurora database?
- Options:
- By adding Aurora Replica instances by using Aurora Auto Scaling
- By changing the instance type
- By creating Amazon CloudWatch alarms
- By creating a scaling policy
- Correct Answer: By adding Aurora Replica instances by using Aurora Auto Scaling
- Why: An Aurora cluster consists of a primary Aurora DB instance and one or more Aurora Replicas. It is possible to scale horizontally by adding read replicas using Aurora Auto Scaling, which helps handle more read traffic.
6. Amazon DynamoDB and Automatic Scaling
Question: How does Amazon DynamoDB perform automatic scaling?
- Options:
- It adds read replicas in response to increased read demand.
- It adjusts the provisioned throughput capacity in response to traffic patterns.
- It adds and removes database instances in response to changes in traffic.
- It changes the instance type in response to changes in processing load.
- Correct Answer: It adjusts the provisioned throughput capacity in response to traffic patterns.
- Why: DynamoDB provisioned mode uses Amazon CloudWatch and AWS Application Auto Scaling to adjust the provisioned throughput capacity of a table within minimum and maximum limits. In addition, DynamoDB on-demand mode scales a table based on actual reads and writes without any limits.
7. Load Balancing for a Custom Protocol
Question: A fleet of Amazon EC2 instances is launched in an Amazon EC2 Auto Scaling group. The instances run an application that uses a custom protocol on TCP port 42000. Connections from client systems on the internet must balance across the instances. Which load balancing solution is the best solution?
- Options:
- Classic Load Balancer
- Application Load Balancer
- Network Load Balancer
- Gateway Load Balancer
- Correct Answer: Network Load Balancer
- Why: A Network Load Balancer can handle TCP, UDP, and TLS network traffic protocols. As a feature of Elastic Load Balancing (ELB), a Network Load Balancer is highly available and is the best choice for high-performance and non-HTTP protocols.
8. Highest Availability for Least Cost and Complexity
Question: A company must build a highly available website that uses server-side scripts to serve dynamic HTML. Which solution provides the HIGHEST availability for the LEAST cost and complexity?
- Options:
- The customer deploys a second web server in another Region. Amazon Route 53 uses failover routing for disaster recovery (DR).
- An Auto Scaling group launches Amazon EC2 instances, which are served by a Network Load Balancer. Amazon Route 53 uses latency-based routing.
- Amazon S3 hosts the website. DNS name resolution points to the S3 bucket.
- An Auto Scaling group launches Amazon EC2 instances, which are served by an Application Load Balancer. DNS name resolution points to the load balancer.
- Correct Answer: An Auto Scaling group launches Amazon EC2 instances, which are served by an Application Load Balancer. DNS name resolution points to the load balancer.
- Why: The Auto Scaling group can automatically launch instances to handle increased load and can terminate instances when they become unhealthy or when the load decreases. The Application Load Balancer is highly available and distributes the load across the instances, providing a resilient and cost-effective architecture for dynamic websites.
9. Redirecting Traffic Based on Health
Question: Users in location A connect to an application in Region A. Users in location B connect to the same application in Region B. If the application in Region A becomes unhealthy, traffic for location A must be redirected to the application in Region B. Which solution meets this requirement?
- Options:
- Use latency-based routing in Amazon Route 53 with Amazon CloudWatch alarms.
- Use geoproximity routing and a Network Load Balancer that is attached to both Regions.
- Use an Application Load Balancer with Amazon CloudWatch alarms.
- Use geolocation routing with failover records in Amazon Route 53.
- Correct Answer: Use geolocation routing with failover records in Amazon Route 53.
- Why: Geolocation routing enables the separation of traffic based on location. A failover record that points to the application in Region B enables failover if the application in Region A becomes unhealthy.
10. Managing a Free Tier Account with Least Effort
Question: A software engineer has created an AWS account for their own personal development and testing. They want the account to stay within the AWS Free Tier and to not generate unexpected costs. Which approach will work and will require the LEAST effort?
- Options:
- Create a service control policy (SCP) to restrict all services that are not included in the AWS Free Tier.
- Create an Amazon CloudWatch alarm to send an email message when the account billing exceeds $0.
- Create an Amazon CloudWatch metric to monitor account billing and limit it to $0.
- Sign in to the AWS Management Console each month and check the billing dashboard.
- Correct Answer: Create an Amazon CloudWatch alarm to send an email message when the account billing exceeds $0.
- Why: Creating an alarm for the estimated charges and receiving a notification when the estimated charges exceed the AWS Free Tier limit is the simplest way to stay informed about potential costs with minimal effort.
Summary Checklist
| Topic | Best AWS Service/Feature |
| Multi-AZ Scaling | Amazon EC2 Auto Scaling |
| Scaling for Known Patterns | Scheduled Scaling |
| Scaling for a Target Metric | Target Tracking Scaling |
| Vertical Database Scaling | Changing Instance Class/Size |
| High Performance/TCP Protocols | Network Load Balancer |
| Managing Free Tier Costs | CloudWatch Billing Alarms |
Check out the full video walkthrough here: YouTube Link
Er. Bikash Subedi
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