A company plans to build a data analytics application in AWS which will be deployed in an Auto Scaling group of On-Demand EC2 instances and a MongoDB database. It is expected that the database will have high-throughput workloads performing small, random I/O operations. As the Solutions Architect, you are required to properly set up and launch the required resources in AWS.
Which of the following is the most suitable EBS type to use for your database?

• A.Provisioned IOPS SSD (io1)
• B.Throughput Optimized HDD (st1)
• C.General Purpose SSD (gp2)
• D.Cold HDD (sc1)

Correct Answer: A

On a given volume configuration, certain I/O characteristics drive the performance behavior for your EBS volumes. SSD-backed volumes, such as General Purpose SSD (gp2) and Provisioned IOPS SSD (io1), deliver consistent performance whether an I/O operation is random or sequential. HDD-backed volumes like Throughput Optimized HDD (st1) and Cold HDD (sc1) deliver optimal performance only when I/O operations are large and sequential.
In the exam, always consider the difference between SSD and HDD as shown on the table below. This will allow you to easily eliminate specific EBS-types in the options which are not SSD or not HDD, depending on whether the question asks for a storage type which has small, random I/O operations or large, sequential I/O operations.

Provisioned IOPS SSD (io1) volumes are designed to meet the needs of I/O-intensive workloads, particularly database workloads, that are sensitive to storage performance and consistency. Unlike gp2, which uses a bucket and credit model to calculate performance, an io1 volume allows you to specify a consistent IOPS rate when you create the volume, and Amazon EBS delivers within 10 percent of the provisioned IOPS performance 99.9 percent of the time over a given year.



General Purpose SSD (gp2) is incorrect because although General Purpose is a type of SSD that can handle small, random I/O operations, the Provisioned IOPS SSD volumes are much more suitable to meet the needs of I/O-intensive database workloads such as MongoDB, Oracle, MySQL, and many others.
Throughput Optimized HDD (st1) and Cold HDD (sc1) are incorrect because HDD volumes (such as Throughput Optimized HDD and Cold HDD volumes) are more suitable for workloads with large, sequential I/O operations instead of small, random I/O operations. References:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html#EBSVolumeTypes_pi ops
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-io-characteristics.html Amazon EBS Overview - SSD vs HDD:
https://youtu.be/LW7x8wyLFvw
Check out this Amazon EBS Cheat Sheet:
https://tutorialsdojo.com/amazon-ebs/

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A company has a web-based order processing system that is currently using a standard queue in Amazon SQS. The IT Manager noticed that there are a lot of cases where an order was processed twice.
This issue has caused a lot of trouble in processing and made the customers very unhappy. The manager has asked you to ensure that this issue will not recur.
What can you do to prevent this from happening again in the future? (Select TWO.)

• A.Use an Amazon SQS FIFO Queue instead.
• B.Change the message size in SQS.
• C.Replace Amazon SQS and instead, use Amazon Simple Workflow service.
• D.Alter the visibility timeout of SQS.
• E.Alter the retention period in Amazon SQS.

Correct Answer: A,C

Amazon SQS FIFO (First-In-First-Out) Queues have all the capabilities of the standard queue with additional capabilities designed to enhance messaging between applications when the order of operations and events is critical, or where duplicates can't be tolerated, for example:
- Ensure that user-entered commands are executed in the right order.
- Display the correct product price by sending price modifications in the right order.
- Prevent a student from enrolling in a course before registering for an account.



Amazon SWF provides useful guarantees around task assignments. It ensures that a task is never duplicated and is assigned only once. Thus, even though you may have multiple workers for a particular activity type (or a number of instances of a decider), Amazon SWF will give a specific task to only one worker (or one decider instance). Additionally, Amazon SWF keeps at most one decision task outstanding at a time for a workflow execution. Thus, you can run multiple decider instances without worrying about two instances operating on the same execution simultaneously. These facilities enable you to coordinate your workflow without worrying about duplicate, lost, or conflicting tasks.
The main issue in this scenario is that the order management system produces duplicate orders at times.
Since the company is using SQS, there is a possibility that a message can have a duplicate in case an EC2 instance failed to delete the already processed message. To prevent this issue from happening, you have to use Amazon Simple Workflow service instead of SQS. Therefore, the correct answers are:
- Replace Amazon SQS and instead, use Amazon Simple Workflow service.
- Use an Amazon SQS FIFO Queue instead.
Altering the retention period in Amazon SQS is incorrect because the retention period simply specifies if the Amazon SQS should delete the messages that have been in a queue for a certain period of time.
Altering the visibility timeout of SQS is incorrect because for standard queues, the visibility timeout isn't a guarantee against receiving a message twice. To avoid duplicate SQS messages, it is better to design your applications to be idempotent (they should not be affected adversely when processing the same message more than once).
Changing the message size in SQS is incorrect because this is not related at all in this scenario.
References:
https://aws.amazon.com/swf/faqs/
https://aws.amazon.com/swf/
https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-visibility-timeou t.html Check out this Amazon SWF Cheat Sheet:
https://tutorialsdojo.com/amazon-simple-workflow-amazon-swf/
Amazon Simple Workflow (SWF) vs AWS Step Functions vs Amazon SQS:
https://tutorialsdojo.com/amazon-simple-workflow-swf-vs-aws-step-functions-vs-amazon-sqs/

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A Solutions Architect is building a cloud infrastructure where EC2 instances require access to various AWS services such as S3 and Redshift. The Architect will also need to provide access to system administrators so they can deploy and test their changes.
Which configuration should be used to ensure that the access to the resources is secured and not compromised? (Select TWO.)

• A.Store the AWS Access Keys in the EC2 instance.
• B.Assign an IAM role to the Amazon EC2 instance.
• C.Store the AWS Access Keys in ACM.
• D.Enable Multi-Factor Authentication.
• E.Assign an IAM user for each Amazon EC2 Instance.

Correct Answer: B,D

In this scenario, the correct answers are:
- Enable Multi-Factor Authentication
- Assign an IAM role to the Amazon EC2 instance
Always remember that you should associate IAM roles to EC2 instances and not an IAM user, for the purpose of accessing other AWS services. IAM roles are designed so that your applications can securely make API requests from your instances, without requiring you to manage the security credentials that the applications use. Instead of creating and distributing your AWS credentials, you can delegate permission to make API requests using IAM roles.

AWS Multi-Factor Authentication (MFA) is a simple best practice that adds an extra layer of protection on top of your user name and password. With MFA enabled, when a user signs in to an AWS website, they will be prompted for their user name and password (the first factor-what they know), as well as for an authentication code from their AWS MFA device (the second factor-what they have). Taken together, these multiple factors provide increased security for your AWS account settings and resources. You can enable MFA for your AWS account and for individual IAM users you have created under your account.
MFA can also be used to control access to AWS service APIs.
Storing the AWS Access Keys in the EC2 instance is incorrect. This is not recommended by AWS as it can be compromised. Instead of storing access keys on an EC2 instance for use by applications that run on the instance and make AWS API requests, you can use an IAM role to provide temporary access keys for these applications.
Assigning an IAM user for each Amazon EC2 Instance is incorrect because there is no need to create an IAM user for this scenario since IAM roles already provide greater flexibility and easier management.
Storing the AWS Access Keys in ACM is incorrect because ACM is just a service that lets you easily provision, manage, and deploy public and private SSL/TLS certificates for use with AWS services and your internal connected resources. It is not used as a secure storage for your access keys. References:
https://aws.amazon.com/iam/details/mfa/
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html Check out this AWS IAM Cheat Sheet:
https://tutorialsdojo.com/aws-identity-and-access-management-iam/

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A Solutions Architect is designing a highly available environment for an application. She plans to host the application on EC2 instances within an Auto Scaling Group. One of the conditions requires data stored on root EBS volumes to be preserved if an instance terminates.
What should be done to satisfy the requirement?

• A.Enable the Termination Protection option for all EC2 instances.
• B.Configure ASG to suspend the health check process for each EC2 instance.
• C.Use AWS DataSync to replicate root volume data to Amazon S3.
• D.Set the value of DeleteOnTermination attribute of the EBS volumes to False.

Correct Answer: D

By default, Amazon EBS root device volumes are automatically deleted when the instance terminates.
However, by default, any additional EBS volumes that you attach at launch, or any EBS volumes that you attach to an existing instance persist even after the instance terminates. This behavior is controlled by the volume's DeleteOnTermination attribute, which you can modify.
To preserve the root volume when an instance terminates, change the DeleteOnTermination attribute for the root volume to False.

This EBS attribute can be changed through the AWS Console upon launching the instance or through CLI/API command.
Hence, the correct answer is the option that says: Set the value of DeleteOnTermination attribute of the EBS volumes to False.
The option that says: Use AWS DataSync to replicate root volume data to Amazon S3 is incorrect because AWS DataSync does not work with Amazon EBS volumes. DataSync can copy data between Network File System (NFS) shares, Server Message Block (SMB) shares, self-managed object storage, AWS Snowcone, Amazon Simple Storage Service (Amazon S3) buckets, Amazon Elastic File System (Amazon EFS) file systems, and Amazon FSx for Windows File Server file systems.
The option that says: Configure ASG to suspend the health check process for each EC2 instance is incorrect because suspending the health check process will prevent the ASG from replacing unhealthy EC2 instances. This can cause availability issues to the application.
The option that says: Enable the Termination Protection option for all EC2 instances is incorrect.
Termination Protection will just prevent your instance from being accidentally terminated using the Amazon EC2 console.
References:
https://aws.amazon.com/premiumsupport/knowledge-center/deleteontermination-ebs/
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/terminating-instances.html Check out this Amazon EBS Cheat Sheet:
https://tutorialsdojo.com/amazon-ebs/

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A company has an On-Demand EC2 instance with an attached EBS volume. There is a scheduled job that creates a snapshot of this EBS volume every midnight at 12 AM when the instance is not used.
One night, there has been a production incident where you need to perform a change on both the instance and on the EBS volume at the same time when the snapshot is currently taking place.
Which of the following scenario is true when it comes to the usage of an EBS volume while the snapshot is in progress?

• A.The EBS volume cannot be used until the snapshot completes.
• B.The EBS volume can be used in read-only mode while the snapshot is in progress.
• C.The EBS volume can be used while the snapshot is in progress.
• D.The EBS volume cannot be detached or attached to an EC2 instance until the snapshot completes

Correct Answer: C

Snapshots occur asynchronously; the point-in-time snapshot is created immediately, but the status of the snapshot is pending until the snapshot is complete (when all of the modified blocks have been transferred to Amazon S3), which can take several hours for large initial snapshots or subsequent snapshots where many blocks have changed.

While it is completing, an in-progress snapshot is not affected by ongoing reads and writes to the volume hence, you can still use the EBS volume normally.
When you create an EBS volume based on a snapshot, the new volume begins as an exact replica of the original volume that was used to create the snapshot. The replicated volume loads data lazily in the background so that you can begin using it immediately. If you access data that hasn't been loaded yet, the volume immediately downloads the requested data from Amazon S3, and then continues loading the rest of the volume's data in the background.
References:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-creating-snapshot.html
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSSnapshots.html
Check out this Amazon EBS Cheat Sheet:
https://tutorialsdojo.com/amazon-ebs/

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