Notes on: Linux Academy: AWS CSAA: 21) How to Prepare for the Exam

Just a place to put some notes on the “AWS Certified Solutions Architect - Associate (New!)” course from https://linuxacademy.com

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Image: The Certified Solutions Architect Exam

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Quiz: Final Exam

Q: A colleague would like a new subnet configured in AWS for a database cluster she is building. She expects that the subnet will never need more than six IP addresses. Which of the following will likely be the most appropriate choice for this subnet?
A: A /28 private subnet
E: Databases generally do not require public access from the Internet, so a private subnet is likely the better choice from a security perspective. /28 is the smallest possible subnet in an AWS VPC.

Q: Company B provides an online image recognition service and utilizes SQS to decouple system components for scalability. The SQS consumer's readers poll the image queue as often as possible to keep end-to-end throughput as high as possible. However, Company B is realizing that polling in tight loops is burning CPU cycles and increasing costs with empty responses. How can company B reduce the number of empty responses?
A: Enable long polling by setting the ReceiveMessageWaitTimeSeconds to a number > 0

Q: The KPL is an easy-to-use, highly-configurable library that helps you write to an Amazon Kinesis stream. It acts as an intermediary between your producer application code and the stream's API actions. One of its key concepts is aggregation. Which of the following best describes aggregation as it relates to the KPL?
A: It refers to the storage of multiple records in a stream's record and allows customers to increase the number of records sent per API call, which effectively increases producer throughput.

Q: While implementing a disaster recovery strategy in another region, you are attempting to move the data from one EBS volume to another in a separate region. What is the best way to do this? Keep in mind this is not a live production replication copy.
A: Take a snapshot of the EBS volume and copy it to the desired region

Q: Elasticity is a fundamental property of the cloud. What best describes elasticity?
A: Power to scale computing resources up and down easily with minimal friction

Q: If an instance that belongs to an Elastic Load Balancer's health check fails, what occurs to the instance that fails?
A: The ELB will de-register the instance and stop sending traffic to the unhealthy instance

Q: Your company is posting a big article on the front page of your website tomorrow. It is expected that the demand could potentially overwhelm your infrastructure. In the event of a load failure, how can you set up DNS failover to a static website?
A: Use Route 53 and the failover option to failover to a static S3 website bucket or CloudFront distribution in the event of an issue

Q: As part of your application architecture requirements, the company you are working for has requested the ability to run analytics against all combined log files from the Elastic Load Balancer. Which services are used together to collect logs and process log file analysis in an AWS environment?
A: Amazon S3 for storing ELB log files and Amazon EMR for processing the log files in analysis

Q: You recently purchased and deployed four reserved EC2 instances in the US-East-1 region’s Availability Zone 1 for a new project. Your supervisor just informed you that this project only requires two EC2 instances. Rather than selling the reserved instances, she asked you to terminate the extra instances and convert two of the on-demand instances already running in Availability Zone 1 to reserved instances. Can this be done?
A: Yes, you can terminate the reserved instances and AWS will automatically begin billing the two on-demand instances as reserved instances
E: If you own three Reserved Instances with the same instance type and Availability Zone, the billing system checks each hour to see how many total instances you have running that match those parameters. If it is three or less, you will be charged the Reserved Instance rate for each instance running that hour.

Q: Your supervisor asks you to create a highly available, decoupled web application. Which of the following does not help you accomplish this goal?
A: IAM user credentials on EC2 instances to grant permissions to modify an SQS queue
E: Elastic Load Balancers, Auto Scaling, and SQS can all play a part in a highly available, decoupled web application. IAM user credentials should not be stored on a EC2 instance.

Q: While implementing a disaster recovery strategy in another region, you attempt to move the data from one EBS volume to another in a separate region. What is the best way to do this? Keep in mind this is not a live production replication copy.
A: Take a snapshot of the EBS volume and copy it to the desired region

Q: Your AWS environment contains several on-demand EC2 instances dedicated to a project that has just been cancelled. Your supervisor does not want to incur charges for these on-demand instances but also does not want to lose the data just yet because there is a chance the project may be revived in the next few days. What should you do to minimize charges for these instances in the meantime?
A: Stop the instances as soon as possible
E: You should not terminate an instance that you may need to place back into production in a few days. The best way to minimize charges is to stop the instances to avoid any data transfer charges that the instance might incur if left running.

Q: Your company is posting a big article on the front page of your website tomorrow. It is expected that the demand could potentially overwhelm your infrastructure. In the event of a load failure, how can you set up DNS failover to a static website?
A: Use Route 53 and the failover option to failover to a static S3 website bucket or CloudFront distribution in the event of an issue

Q: When designing a cloud service based on AWS and you choose to use RRS on S3 instead of S3 standard storage type, what type of trade offs do you have to build your application around?
A: RRS only has 99.99% durability and you have to design automation around replacing lost objects

Q: One of your more important clients is a Telecom business who needs to process some real-time data in a distributed manner. They suggest to you that they think they should use either Amazon SQS or Amazon Kinesis to achieve this and they want you to tell them what would be the difference between the two. After some research, you decide that they should use Kinesis and are trying to put together some reasons for this. One of the below statements is INCORRECT, regarding this. Which one?
A: Kinesis cannot route related data records to the same record processor (as in streaming MapReduce).
E: Kinesis can route related data records to the same record processor

Q: Which of the following best describes what "bastion hosts" are?
A: Bastion hosts are instances that sit within your public subnet and are typically accessed using SSH or RDP. Once remote connectivity has been established with a bastion host, it then acts as a ‘jump’ server, allowing you to use SSH or RDP to log in to other instances (within private subnets) deeper within your network.

Q: You and a colleague create an SQS queue and create several messages in it. You both test your ability to manually poll the queue by using the command-line API calls. After testing, you find that your colleague’s polling attempt retrieved messages 1, 3, and 5. Your polling attempt retrieved messages 4, 6, and 8. Nether of your attempts retrieved messages 2 or 7. What is a possible cause for this behavior?
A1: You and your colleague did not see the same messages because of the visibility timeout
A2: You and your colleague used short polling
E: When a message is retrieved, that message is hidden from other polling attempts until the message is deleted or the visibility timeout expires. Short polling does not query all the servers that the SQS messages can reside on, so multiple queries of the queue may be needed to retrieve all messages in the queue.

T: The AMI ID used in an Auto Scaling policy is configured in the Launch configuration

Q: When reviewing the Auto Scaling events, it is noticed that an application is scaling up and down multiple times within the hour. What design change could you make to optimize cost while preserving elasticity?
A: Change the scale down CloudWatch metric to a higher threshold

T: You cannot deny the AWS root account to EC2 instances via IAM policy.

Q: By default, is data in S3 encrypted?
A: No, but it can be when the right APIs are called for SSE

Q: You are working for a startup company that is building an application that receives large amounts of data. Unfortunately, current funding has left the startup short on cash, unable to afford thousands of dollars of storage hardware. The company has opted to use AWS. Which services would you implement to store a virtually unlimited amount of data without any effort to scale when demand unexpectedly increases?
A: Amazon S3, because it provides unlimited amounts of storage data, scales automatically, is highly available, and durable

T: Amazon SQS (Simple Queue Service) guarantees delivery of AT LEAST 1 message but cannot guarantee it will not create duplicates.

Q: You are consulting for a healthcare company that has strict compliance and auditing requirements. When architecting the application environment on AWS, which services or service features might you enable to take advantage of monitoring to ensure auditing the environment for compliance is easy and follows the strict healthcare compliance requirements?
A: CloudTrail for security logs

Q: If your organization is concerned about storing sensitive data in the cloud, you should:
A1: Encrypt the file system on an EBS volume using Linux tools
A2: Enable EBS Encyption
A3: Enable S3 Encryption

Q: You are designing a global application that takes advantage of multiple regions. As part of your application, the need to synchronize from one region to another is required to ensure your application is serving the same data when employing latency-based Route 53 DNS records. To ensure this happens, you have determined that using the AWS CLI to sync files from the primary storage servers to S3 is the best method. How might you implement AWS CLI authentication against the S3 service?
A: Create an EC2 IAM role and assign it to each EC2 instance that utilizes the AWS CLI to sync the data

Q: What is the difference between an Availability Zone and an edge location?
A: An Availability Zone is an Amazon resource within an AWS region, whereas an edge location will deliver cached content to the closest location to reduce latency

Q: Currently, you're helping design and architect a highly-available application. After building the initial environment, you've found that part of your application does not work correctly until port 443 is added to the security group. After adding port 443 to the appropriate security group, how much time will it take before the changes are applied and the application begins working correctly?
A: Changes apply instantly to the security group, and the application should be able to imediately respond to 443 requests

Q: Your supervisor asks you to create a highly available website which serves static content from EC2 instances. Which of the following is not a requirement to accomplish this goal?
A: An SQS queue
E: While an SQS queue can be an important part of a multi-step decoupled web application, it is not necessary to host a highly-available static website on EC2. An Auto Scaling group configured to deploy EC2 instances in multiple subnets located in multiple Availability Zones allows an application to remain online despite an instance or AZ failure.

Q: Your company wants to back up the onsite file server to AWS but does not want to serve the files from S3 to your office network when files need to be accessed. Which service and setup would you use to accomplish this task?
A: Use Amazon Storage Gateway and gateway-stored volumes to store the data locally and asynchronously backup point-in-time snapshots to S3

Q: A user needs access to Elastic Load Balancing. This is the first and possibly only time that they will require this access. Which of the following choices would be the best way to allow this access?
A: Delegate access to the ELB using an IAM role

Q: You own an image manipulation application. Your users take a picture, upload it to your app, and request filters to be added to the image. You need to decouple the application so your users are not waiting for the image processing to take place. How would you go about doing this?
A: Use Amazon SQS to store the requests using metadata and JSON in the message, use S3 to store the image, and Auto Scaling to determine when to fire off more worker instances based on queue size

Q: You have 5 Cloudformation templates. Each template is for a different application architecture. These architectures vary between your blog apps and your gaming apps. What determines the cost of using the Cloudformation templates?
A: CloudFormation does not have a cost but you are charged for the underlying resources it builds

Q: Your application's usage peaks at 90% during the hours of 9 AM and 10 AM everyday. All other hours require only 10% of the peak resources. What is the best way to scale your application so you're only paying for max resources during peak hours?
A: Proactive Cycle Scaling

Q: You are asked to review a plan that your company has made to create a new application that makes use of SQS, EC2, Auto Scaling, and CloudWatch. Which of the following action items should you advise your company not to implement?
A: Utilize short polling with a wait time of 20 seconds to reduce the number of empty responses from the SQS queue
E: Polling executed with a wait time of greater than 0 seconds is called long polling.

FALSE: When a snapshot is being taken against an EBS volume, the volume becomes unavailable and the instance no longer has the ability to communicate with the EBS volume until the snapshot is complete.

Q: Your EC2 instances are configured to run behind an Amazon VPC. You have assigned two web servers instances to an Elastic Load Balancer. However, the instances and the ELB are not reachable via URL to the elastic load balancer serving the web app data from the EC2 instances. How might you resolve the issue so that your instances are serving the web app data to the public Internet?
A: Attach an internet gateway to the VPC and route it to the subnet

Q: You create an SQS queue with the default settings for a new application your company is deploying. While new messages are added to the queue throughout the week, management has indicated that the application which retrieves the messages should only be run during your company’s weekly Sunday evening maintenance window. It is quickly noticed on Monday morning that several messages were not processed the previous evening and the messages are no longer in the queue. What is a likely cause for this issue?
A: The messages surpassed the retention period for the queue
E: The default message retention period for an SQS queue is four days, so messages older than four days would have been deleted.

Q: Your company has an application that requires access to a NoSQL database. Your IT department has no desire to manage the NoSQL servers. Which Amazon service provides a fully-managed and highly available NoSQL service?
A: DynamoDB

Q: An AWS VPC (Virtual Private Cloud) allows you to…
A: …connect your cloud resources to your own encrypted IPSec VPN connections

Q: In order to establish a successful site-to-site VPN connection from your on-premises network to the VPC (Virtual Private Cloud), which of the following needs to be configured inside of the VPC?
A: A public IP address on the customer gateway for the on-premise network
E: When you configure a VPN, you're configuring it from the VPC and from the on-premises network. You are taking information (the public IP) from the on-premises network and configuring it inside of the VPC.

T: Auto Scaling is a tool used for creating elastic and self-healing applications.

Q: For basic monitoring on AWS, which metrics are not included as part of the basic monitoring package?
A1: Free memory
A2: Free swap

T: Amazon Auto Scaling is not meant to handle instant load spikes but is built to grow with a gradual increase in usage over a short time period.

Q: Your AWS environment contains several reserved EC2 instances dedicated to a project that has just been cancelled. Your supervisor wants to stop incurring charges for these reserved instances immediately and recuperate as much of the reserved instance cost as possible. What can you do to avoid being charged for them?
A: Terminate the instances as soon as possible, Sell the reserved instances on the AWS Reserved Instance Marketplace
E: You should terminate the instance to avoid any data transfer charges that the instance might incur if left running and sell the reserved instance in the AWS Reserved Instance Marketplace to recuperate cost.

Q: In AWS, when a request is made, the AWS service decides whether a given request should be allowed or denied. The distinction between a request being denied or allowed by default and an explicit deny in a policy is important. Which of the following statements best describes this distinction?
A: By default, a request is denied, but this can be overridden by an allow. In contrast, if a policy explicitly denies a request, that deny can't be overridden.

T: US-East-1 supports Multi-AZ RDS deployments.

Q: Your supervisor asks you to create a decoupled application whose process includes dependencies on EC2 instances and servers located in your company’s on-premises datacenter. Which of these are you least likely to recommend as part of that process?
A: SQS polling from an EC2 instance using IAM user credentials
E: An EC2 IAM role should be used when deploying EC2 instances to grant permissions rather than storing IAM user credentials in EC2 instances

Q: You manage an application that uses EC2 instances and SQS to process requests from end users. Your application is working great, but your supervisor is concerned about the cost of the AWS resources it uses. Which of the following would not help address that concern?
A: Increase the visibility timeout for messages in the SQS queue

Q: Your company has moved a legacy application from an on-premises data center to the cloud. The legacy application requires a static IP address hard-coded into the backend, which prevents you from deploying the application with high availability and fault tolerance using the ELB. Which steps would you take to apply high availability and fault tolerance to this application?
A1: Ensure that the instance it's using has an elastic IP address assigned to it
A2: Write a custom script that pings the health of the instance, and, if the instance stops responding, switches the elastic IP address to a standby instance

Q: Which statement is true about Amazon SQS?
A1: Amazon SQS (Simple Queue Service) guarantees delivery of AT LEAST 1 message but cannot guarantee it will not create duplicates.
A2: Amazon SQS guarantees delivery of AT LEAST 1 message but cannot guarantee message order, although does attempt to.

Q: Your company is moving their entire 20 TB data warehouse to the cloud. With your current bandwidth it would take 2 months to transfer the data. Which service would allow you to quickly get your data into AWS?
A: Amazon Import/Export

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