Amazon DOP-C01 Practice Test - Questions Answers, Page 14
List of questions
Question 131
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A company requires its internal business teams to launch resources through pre-approved AWS CloudFormation templates only. The security team requires automated monitoring when resources drift from their expected state. Which strategy should be used to meet these requirements?
Explanation:
Reference: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-stack-drift.html
Question 132
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A company needs to introduce automatic DNS failover for a distributed web application to a disaster recovery or standby installation. The DevOps Engineer plans to configure Amazon Route 53 to provide DNS routing to alternate endpoint in the event of an application failure.
What steps should the Engineer take to accomplish this? (Choose two.)
Question 133
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A law firm is running a web application on AWS. The system manages legal documents uploaded by users, and stores the documents in Amazon S3. Users have complained that file uploads are taking too long and there are timeouts during peak usage. A DevOps engineer found that web servers are managing concurrent uploads and are overloaded. Which actions should be taken to troubleshoot the issue in the MOST cost-effective manner?
Explanation:
Reference: https://aws.amazon.com/premiumsupport/knowledge-center/s3-troubleshoot-slow-downloads-uploads/
Question 134
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A defect was discovered in production and a new sprint item has been created for deploying a hotfix. However, any code change must go through the following steps before going into production:
Scan the code for security breaches, such as password and access key leaks. Run the code through extensive, longrunning unit tests. Which source control strategy should a DevOps Engineer use in combination with AWS CodePipeline to complete this process?
Question 135
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A Development team is adding a new country to an e-commerce application. This addition requires that new application features be added to the shipping component of the application. The team has not decided if all new features should be added, as some will take approximately six weeks to build. While the final decision on the shipping component features is being made, other team members are continuing to work on other features of the application. Based on this situation, how should the application feature deployments be managed?
Question 136
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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?
Question 137
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You are creating a new API for video game scores. Reads are 100 times more common than writes, and the top 1% of scores are read 100 times more frequently than the rest of the scores. What's the best design for this system, using DynamoDB?
Explanation:
Because the 100x read ratio is mostly driven by a small subset, with caching, only a roughly equal number of reads to writes will miss the cache, since the supermajority will hit the top 1% scores. Knowing we need to set the values roughly equal when using caching, we select AWS ElastiCache, because CloudFront cannot directly cache DynamoDB queries, and ElastiCache is an excellent in-memory cache for database queries, rather than a distributed proxy cache for content delivery.
... One solution would be to cache these reads at the application layer. Caching is a technique that is used in many highthroughput applications, offloading read activity on hot items to the cache rather than to the database. Your application can cache the most popular items in memory, or use a product such as ElastiCache to do the same.
Reference:
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/bestpractices.html#%20Guideli%20nesForTables.CachePopularItem
Question 138
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A DevOps engineer needs to grant several external contractors access to a legacy application that runs on an Amazon Linux Amazon EC2 instance. The application server is available only in a private subnet. The contractors are not authorized for VPN access.
What should the DevOps engineer do to grant the contactors access to the application server?
Question 139
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You run operations for a company that processes digital wallet payments at a very high volume. One second of downtime, during which you drop payments or are otherwise unavailable, loses you on average USD 100. You balance the financials of the transaction system once per day.
Which database setup is best suited to address this business risk?
Explanation:
Only the multi-master, multi-region DynamoDB answer makes sense. Multi-AZ deployments do not provide sufficient availability when a business loses USD 360,000 per hour of unavailability. As RDS does not natively support multi-region, and ACID does not perform well/at all over large distances between regions, only the DynamoDB answer works.
Reference: http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Streams.CrossRegionRepl.html
Question 140
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For AWS CloudFormation, which stack state refuses UpdateStack calls?
Explanation:
When a stack is in the UPDATE_ROLLBACK_FAILED state, you can continue rolling it back to return it to a working state (to UPDATE_ROLLBACK_COMPLETE). You cannot update a stack that is in the UPDATE_ROLLBACK_FAILED state.
However, if you can continue to roll it back, you can return the stack to its original settings and try to update it again.
Reference: http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stackscontinueupdaterollback.html
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