Amazon DOP-C01 Practice Test - Questions Answers, Page 19
List of questions
Question 181
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A company is using AWS Organizations to create separate AWS accounts for each of its departments. It needs to automate the following tasks:
Updating the Linux AMIs with new patches periodically and generating a golden image Installing a new version of Chef agents in the golden image, if available Enforcing the use of the newly generated golden AMIs in the department's account Which option requires the LEAST management overhead?
Question 182
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You work for a company that automatically tags photographs using artificial neural networks (ANNs), which run on GPUs using C++. You receive millions of images at a time, but only 3 times per day on average. These images are loaded into an AWS S3 bucket you control for you in a batch, and then the customer publishes a JSON-formatted manifest into another S3 bucket you control as well. Each image takes 10 milliseconds to process using a full GPU. Your neural network software requires 5 minutes to bootstrap. Image tags are JSON objects, and you must publish them to an S3 bucket. Which of these is the best system architectures for this system?
Explanation:
The Elastic Beanstalk option is incorrect because it requires a constantly-polling instance, which may break and costs money. The Lambda fleet option is incorrect because AWS Lambda does not support GPU usage. The OpsWorks stack option both requires a constantly-polling instance, and also requires complex timing and capacity planning logic. The CloudFormation option requires no polling, has no always-on instances, and allows arbitrarily fast processing by simply setting the instance count as high as needed.
Reference: http://docs.aws.amazon.com/lambda/latest/dg/current-supported-versions.html
Question 183
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Your application uses CloudFormation to orchestrate your application's resources. During your testing phase before the application went live, your Amazon RDS instance type was changed and caused the instance to be re-created, resulting In the loss of test data. How should you prevent this from occurring in the future?
Question 184
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A company uses Amazon S3 to store proprietary information. The Development team creates buckets for new projects on a daily basis. The Security team wants to ensure that all existing and future buckets have encryption, logging, and versioning enabled. Additionally, no buckets should ever be publicly read or write accessible.
What should a DevOps Engineer do to meet these requirements?
Explanation:
Reference: https://aws.amazon.com/blogs/aws/aws-config-update-new-managed-rules-to-secure-s3-buckets/
Question 185
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Using the AWS CLI, which command retrieves CloudTrail trail settings, including the status of the trail itself?
Explanation:
You can retrieve trail settings and status using the cloudtrail describe-trails command. It will generate output similar to the example below.
Reference: http://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudtrail-create-and-update-a-trailby-using-the-aws-cli.htm
Question 186
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You are designing a system which needs, at minumum, 8 m4.large instances operating to service traffic. When designing a system for high availability in the us-east-1 region, which has 6 Availability Zones, you company needs to be able to handle death of a full availability zone. How should you distribute the servers, to save as much cost as possible, assuming all of the EC2 nodes are properly linked to an ELB? Your VPC account can utilize us-east-1's AZ's a through f, inclusive.
Explanation:
You need to design for N+1 redundancy on Availability Zones. ZONE_COUNT = (REQUIRED_INSTANCES / INSTANCE_COUNT_PER_ZONE) + 1. To minimize cost, spread the instances across as many possible zones as you can. By using a though e, you are allocating 5 zones. Using 2 instances, you have 10 total instances. If a single zone fails, you have 4 zones left, with 2 instances each, for a total of 8 instances. By spreading out as much as possible, you have increased cost by only 25% and significantly de-risked an availability zone failure. Reference:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts.html
Question 187
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Your company operates an application consisting of an AWS CloudFormation stack that contains a load balancer, an Auto Scaling group of web servers, and an Amazon RDS instance. To save time and costs, you update the current test stack when testing minor changes, and create a new stack for major changes. As part of the testing procedure of your application, each version needs to be registered once and only once with a Configuration Management Database (CMDB).
What cost-effective solution should you choose to perform this registration?
Question 188
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What is a circular dependency in AWS CloudFormation?
Explanation:
To resolve a dependency error, add a DependsOn attribute to resources that depend on other resources in your template. In some cases, you must explicitly declare dependencies so that AWS CloudFormation can create or delete resources in the correct order. For example, if you create an Elastic IP and a VPC with an Internet gateway in the same stack, the Elastic IP must depend on the Internet gateway attachment. For additional information, see DependsOn Attribute.
Reference:
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/troubleshooting.html#trouble%20shootin%20g-errorsdependence-error
Question 189
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Your application uses Amazon SQS and Auto Scaling to process background jobs. The Auto Scaling policy is based on the number of messages in the queue, with a maximum Instance count of 100. Since the application was launched, the group has never scaled above 50. The Auto Scaling group has now scaled to 100, the queue size is increasing, and very few Jobs are being completed. The number of messages being sent to the queue is at normal levels. What should you do to identify why the queue size is unusually high, and to reduce it?
Question 190
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An application that runs on Amazon EC2 instances behind an Application Load Balancer is deployed using AWS Elastic Beanstalk. During a recent rolling deployment, users experienced application errors even though application health checks were passing on all instances. A log analysis shows that the errors were caused by user requests being processed by two different versions of the application behind the same load balancer. The analysis also shows a recent change made the responses backward incompatible.
Which deployment method will address these issues?
Explanation:
Reference: https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.rolling-version-deploy.html
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