Amazon DOP-C01 Online Practice Questions and Exam Preparation

Amazon DOP-C01 Online Questions & Answers

• Question 461:

  When using Amazon SQS how much data can you store in a message?

  A. 8 KB
  B. 2 KB
  C. 16 KB
  D. 4 KB
  A. 8 KB

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  With Amazon SQS version 2008-01-01, the maximum message size for both SOAP and Query requests is 8KB. If you need to send messages to the queue that are larger than 8 KB, AWS recommends that you split the information into separate messages. Alternatively, you could use Amazon S3 or Amazon SimpleDB to hold the information and include the pointer to that information in the Amazon SQS message. If you send a message that is larger than 8KB to the queue, you will receive a MessageTooLong error with HTTP code 400.

• Question 462:

  A new zero-day vulnerability was found in OpenSSL requiring the immediate patching of a production web fleet running on Amazon Linux. Currently, OS updates are performed manually on a monthly basis and deployed using updates to the production Auto Scaling Group's launch configuration. Which method should a DevOps Engineer use to update packages in-place without downtime?

  A. Use AWS CodePipline and AWS CodeBuild to generate new copies of these packages, and update the Auto Scaling group's launch configuration.
  B. Use AWS Inspector to run "yum upgrade" on all running production instances, and manually update the AMI for the next maintenance window.
  C. Use Amazon EC2 Run Command to issue a package update command to all running production instances, and update the AMI for future deployments.
  D. Define a new AWS OpsWorks layer to match the running production instances, and use a recipe to issue a package update command to all running production instances.
  C. Use Amazon EC2 Run Command to issue a package update command to all running production instances, and update the AMI for future deployments.

• Question 463:

  You are using Elastic Beanstalk to manage your e-commerce store. The store is based on an open source e- commerce platform and is deployed across multiple instances in an Auto Scaling group. Your development team often creates new "extensions" for the e-commerce store. These extensions include PHP source code as well as an SQL upgrade script used to make any necessary updates to the database schema. You have noticed that some extension deployments fail due to an error when running the SQL upgrade script. After further investigation, you realize that this is because the SQL script is being executed on all of your Amazon EC2 instances.

  How would you ensure that the SQL script is only executed once per deployment regardless of how many Amazon EC2 instances are running at the time?

  A. Use a "Container command" within an Elastic Beanstalk configuration file to execute the script, ensuring that the "leader only" flag is set to true.
  B. Make use of the Amazon EC2 metadata service to query whether the instance is marked as the leader" in the Auto Scaling group. Only execute the script if "true" is returned.
  C. Use a "Solo Command" within an Elastic Beanstalk configuration file to execute the script. The Elastic Beanstalk service will ensure that the command is only executed once.
  D. Update the Amazon RDS security group to only allow write access from a single instance in the Auto Scaling group; that way, only one instance will successfully execute the script on the database.
  A. Use a "Container command" within an Elastic Beanstalk configuration file to execute the script, ensuring that the "leader only" flag is set to true.

• Question 464:

  A DevOps Engineer is working with an application deployed to 12 Amazon EC2 instances across 3 Availability Zones. New instances can be started from an AMI image. On a typical day, each EC2 instance has 30% utilization during business hours and 10% utilization after business hours. The CPU utilization has an immediate spike in the first few minutes of business hours. Other increases in CPU utilization rise gradually.

  The Engineer has been asked to reduce costs while retaining the same or higher reliability. Which solution meets these requirements?

  A. Create two Amazon CloudWatch Events rules with schedules before and after business hours begin and end. Create two AWS Lambda functions, one invoked by each rule. The first function should stop nine instances after business hours end, the second function should restart the nine instances before the business day begins.
  B. Create an Amazon EC2 Auto Scaling group using the AMI image, with a scaling action based on the Auto Scaling group's CPU Utilization average with a target of 75%. Create a scheduled action for the group to adjust the minimum number of instances to three after business hours end and reset to six before business hours begin.
  C. Create two Amazon CloudWatch Events rules with schedules before and after business hours begin and end. Create an AWS CloudFormation stack, which creates an EC2 Auto Scaling group, with a parameter for the number of instances. Invoke the stack from each rule, passing a parameter value of three in the morning, and six in the evening.
  D. Create an EC2 Auto Scaling group using the AMI image, with a scaling action based on the Auto Scaling group's CPU Utilization average with a target of 75%. Create a scheduled action to terminate nine instances each evening after the close of business.
  B. Create an Amazon EC2 Auto Scaling group using the AMI image, with a scaling action based on the Auto Scaling group's CPU Utilization average with a target of 75%. Create a scheduled action for the group to adjust the minimum number of instances to three after business hours end and reset to six before business hours begin.

• Question 465:

  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.)

  A. Change the Auto Scaling configuration to replace the instances when they fail the load balancer's health checks.
  B. Change the target group health check HealthCheckIntervalSeconds parameter to reduce the interval between health checks.
  C. Change the target group health checks from HTTP to TCP to check if the port where the application is listening is reachable.
  D. Enable the available memory consumption metric within the Amazon CloudWatch dashboard for the entire Auto Scaling group. Create an alarm when the memory utilization is high. Associate an Amazon SNS topic to the alarm to receive notifications when the alarm goes off.
  E. Use the Amazon CloudWatch agent to collect the memory utilization of the EC2 instances in the Auto Scaling group. Create an alarm when the memory utilization is high and associate an Amazon SNS topic to receive a notification.
  D. Enable the available memory consumption metric within the Amazon CloudWatch dashboard for the entire Auto Scaling group. Create an alarm when the memory utilization is high. Associate an Amazon SNS topic to the alarm to receive notifications when the alarm goes off.
  E. Use the Amazon CloudWatch agent to collect the memory utilization of the EC2 instances in the Auto Scaling group. Create an alarm when the memory utilization is high and associate an Amazon SNS topic to receive a notification.

• Question 466:

  A developer has written an application that writes data to Amazon DynamoDB. The DynamoDB table has been configured to use conditional writes. During peak usage times, writes are failing due to a ConditionalCheckFailedException error. How can the developer increase the application's reliability when multiple clients are attempting to write to the same record?

  A. Write the data to an Amazon SNS topic.
  B. Increase the amount of write capacity for the table to anticipate short-term spikes or bursts in write operations.
  C. Implement a caching solution, such as DynamoDB Accelerator or Amazon ElastiCache.
  D. Implement error retries and exponential backoff with jitter.
  D. Implement error retries and exponential backoff with jitter.

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  Reference: https://aws.amazon.com/premiumsupport/knowledge-center/dynamodb-table-throttled/

• Question 467:

  You are using AWS Elastic Beanstalk to deploy your application and must make data stored on an Amazon Elastic Block Store (EBS) volume snapshot available to the Amazon Elastic Compute Cloud (EC2) instances. How can you modify your Elastic Beanstalk environment so that the data is added to the Amazon EC2 instances every time you deploy your application?

  A. Add commands to a configuration file in the .ebextensions folder of your deployable archive that mount an additional Amazon EBS volume on launch. Also add a "BlockDeviceMappings" option, and specify the snapshot to use for the block device in the Auto Scaling launch configuration.
  B. Add commands to a configuration file in the .ebextensions folder of your deployable archive that uses the create-volume Amazon EC2 API or CLI to create a new ephemeral volume based on the specified snapshot and then mounts the volume on launch.
  C. Add commands to the Amazon EC2 user data that will be executed by eb-init, which uses the create- volume Amazon EC2 API or CLI to create a new Amazon EBS volume based on the specified snapshot, and then mounts the volume on launch.
  D. Add commands to the Chef recipe associated with your environment, use the create-volume Amazon EC2 API or CLI to create a new Amazon EBS volume based on the specified snapshot, and then mount the volume on launch.
  A. Add commands to a configuration file in the .ebextensions folder of your deployable archive that mount an additional Amazon EBS volume on launch. Also add a "BlockDeviceMappings" option, and specify the snapshot to use for the block device in the Auto Scaling launch configuration.

• Question 468:

  What storage driver does Docker generally recommend that you use if it is available?

  A. zfs
  B. btrfs
  C. aufs
  D. overlay
  C. aufs

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  After you have read the storage driver overview, the next step is to choose the best storage driver for your workloads. In making this decision, there are three high-level factors to consider: If multiple storage drivers are supported in your kernel, Docker has a prioritized list of which storage driver to use if no storage driver is explicitly configured, assuming that the prerequisites for that storage driver are met: If aufs is available, default to it, because it is the oldest storage driver. However, it is not universally available.

  Reference: https://docs.docker.com/engine/userguide/storagedriver/selectadriver/

• Question 469:

  You recently encountered a major bug in your Windows-based web application during a deployment cycle. During this failed deployment, it took the team four hours to roll back to a previously working state, which left customers with a poor user experience. During the post-mortem, your team discussed the need to provide a quicker way to roll back failed deployments. You currently run your web application on Amazon EC2 using Windows 2012R2 and use Elastic Load Balancing for your load balancing needs. Which technique should you use to solve this problem?

  A. Create deployable versioned bundles of your application. Store the bundles on Amazon S3. Re-deploy your web application on Elastic Beanstalk, and enable the Elastic Beanstalk autorollback feature tied to CloudWatch metrics that define failure.
  B. Re-deploy your web application using an AWS OpsWorks stack, and use the AWS OpsWorks auto- rollback feature to initiate a rollback during failures.
  C. Create deployable versioned bundles of your application. Store the bundle on Amazon S3. Re-deploy your web application using an AWS OpsWorks stack, and use AWS OpsWorks application versioning to initiate a rollback during failures.
  D. Re-deploy your web application using Elastic Beanstalk, and use the Elastic Beanstalk application versions when deploying. During failures, re-deploy the previous version to the Elastic Beanstalk environment.
  E. Re-deploy your web application using Elastic Beanstalk, and use the Elastic Beanstalk API to trigger a FailedDeployment API call to initiate a rollback to the previous version.
  B. Re-deploy your web application using an AWS OpsWorks stack, and use the AWS OpsWorks auto- rollback feature to initiate a rollback during failures.

• Question 470:

  What is the proper (best practice) way to begin a playbook?

  A. - hosts: all
  B. ...
  C. ###
  D. --
  D. --

  ---

  All YAML files can begin with `---' and end with `...' to indicate where YAML starts and ends. While this is optional, it is considered best practice.

  Reference: http://docs.ansible.com/ansible/YAMLSyntax.html