Amazon DOP-C01 Practice Test - Questions Answers, Page 30
List of questions
Question 291
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A DevOps engineer notices that all Amazon EC2 instances running behind an Application Load Balancer in an Auto Scaling group are failing to respond to user requests. The EC2 instances are also failing target group HTTP health checks. Upon inspection, the engineer notices the application process was not running in any EC2 instances. There are a significant number of out of memory messages in the system logs. The engineer needs to improve the resilience of the application to cope with a potential application memory leak. Monitoring and notifications should be enabled to alert when there is an issue. Which combination of actions will meet these requirements? (Choose two.)
Question 292
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How does Amazon RDS multi Availability Zone model work?
Explanation:
In a Multi-AZ deployment, Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone.
Reference: http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html
Question 293
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You have been tasked with deploying a scalable distributed system using AWS OpsWorks. Your distributed system is required to scale on demand. As it is distributed, each node must hold a configuration file that includes the hostnames of the other instances within the layer.
How should you configure AWS OpsWorks to manage scaling this application dynamically?
Question 294
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What flag would you use to limit a Docker container's memory usage to 128 megabytes?
Explanation:
Docker can enforce hard memory limits, which allow the container to use no more than a given amount of user or system memory, or soft limits, which allow the container to use as much memory as it needs unless certain conditions are met, such as when the kernel detects low memory or contention on the host machine. Some of these options have different effects when used alone or when more than one option is set. Most of these options take a positive integer, followed by a suffix of b, k, m, g, to indicate bytes, kilobytes, megabytes, or gigabytes.
Option -m or --memory=
Description The maximum amount of memory the container can use. If you set this option, the minimum allowed value is 4m (4 megabyte).
Reference: https://docs.docker.com/engine/admin/resource_constraints/#memory
Question 295
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You need to create an audit log of all changes to customer banking data. You use DynamoDB to store this customer banking data. It is important not to lose any information due to server failures. What is an elegant way to accomplish this?
Explanation:
All suggested periodic options are sensitive to server failure during or between periodic flushes. Streaming to Lambda and then logging to CloudWatch Logs will make the system resilient to instance and Availability Zone failures.
Reference: http://docs.aws.amazon.com/lambda/latest/dg/with-ddb.html
Question 296
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A developer is building an application that must allow users to upload images to an Amazon S3 bucket. Users need to be able to sign in to the application using Facebook to upload images. How can these requirements be met?
Explanation:
Reference: https://aws.amazon.com/blogs/mobile/store-your-photos-in-the-cloud-using-amazon-s3/
Question 297
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A DevOps Engineer is reviewing a system that uses Amazon EC2 instances in an Auto Scaling group. This system uses a configuration management tool that runs locally on each EC2 instance. Because of the volatility of the application load, new instances must be fully functional within 3 minutes of entering a running state. Current setup tasks include:
Installing the configuration management agent – 2 minutes
Installing the application framework – 15 minutes
Copying configuration data from Amazon S3 – 2 minutes
Running the configuration management agent to configure instances – 1 minute Deploying the application code from Amazon S3 – 2 minutes How should the Engineer set up the system so it meets the launch time requirement?
Question 298
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A company runs an application on one Amazon EC2 instance. Application metadata is stored in Amazon S3 and must be retrieved if the instance is restarted. The instance must restart or relaunch automatically if the instance becomes unresponsive.
Which solution will meet these requirements?
Explanation:
Reference: https://aws.amazon.com/premiumsupport/knowledge-center/opsworks-unexpected-start-instance/
Question 299
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Your CTO has asked you to make sure that you know what all users of your AWS account are doing to change resources at all times. She wants a report of who is doing what over time, reported to her once per week, for as broad a resource type group as possible. How should you do this?
Explanation:
This is the ideal use case for AWS CloudTrail. CloudTrail provides visibility into user activity by recording API calls made on your account. CloudTrail records important information about each API call, including the name of the API, the identity of the caller, the time of the API call, the request parameters, and the response elements returned by the AWS service. This information helps you to track changes made to your AWS resources and to troubleshoot operational issues. CloudTrail makes it easier to ensure compliance with internal policies and regulatory standards.
Reference:
https://aws.amazon.com/cloudtrail/faqs/
Question 300
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During metric analysis, your team has determined that the company's website is experiencing response times during peak hours that are higher than anticipated. You currently rely on Auto Scaling to make sure that you are scaling your environment during peak windows. How can you improve your Auto Scaling policy to reduce this high response time? (Choose two.)
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