AWS Certified Developer Associate

A company uses Elastic Beanstalk to manage its IT infrastructure on AWS Cloud and it would like to deploy the new application version to the EC2 instances. When the deployment is executed, some instances should serve requests with the old application version, while other instances should serve requests using the new application version until the deployment is completed. Which deployment meets this requirement without incurring additional costs?

Rolling Deployment will be used.The rolling deployment policy deploys the new version in batches. Each batch is taken out of service during the deployment phase, reducing your environment's capacity by the number of instances in a batch. The cost remains the same as the number of EC2 instances does not increase. This policy avoids downtime and minimises reduced availability, at a cost of a longer deployment time.

With Elastic Beanstalk, you can quickly deploy and manage applications in the AWS Cloud without having to learn about the infrastructure that runs those applications. Elastic Beanstalk reduces management complexity without restricting choice or control. You simply upload your application, and Elastic Beanstalk automatically handles the details of capacity provisioning, load balancing, scaling, and application health monitoring.

https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/Welcome.html

A developer is testing Amazon Simple Queue Service (SQS) queues in a development environment. The queue along with all its contents has to be deleted after testing.

Which SQS API should be used for this requirement?

DeleteQueue - Deletes the queue specified by the QueueUrl, regardless of the queue's contents. When you delete a queue, any messages in the queue are no longer available.

When you delete a queue, the deletion process takes up to 60 seconds. Requests you send involving that queue during the 60 seconds might succeed. For example, a SendMessage request might succeed, but after 60 seconds the queue and the message you sent no longer exist.

When you delete a queue, you must wait at least 60 seconds before creating a queue with the same name.

A developer has been asked to create a web application to be deployed on EC2 instances. The developer just wants to focus on writing application code without worrying about server provisioning, configuration and deployment. As a Developer Associate, which AWS service would you recommend for the given use-case?

Elastic Beanstalk - AWS Elastic Beanstalk provides an environment to easily deploy and run applications in the cloud. It is integrated with developer tools and provides a one-stop experience for you to manage the lifecycle of your applications.

AWS Elastic Beanstalk lets you manage all of the resources that run your application as environments where each environment runs only a single application version at a time. When an environment is being created, Elastic Beanstalk provisions all the required resources needed to run the application version. You don't need to worry about server provisioning, configuration, and deployment as that's taken care of by Beanstalk.

Your global organization has an IT infrastructure that is deployed using CloudFormation on AWS Cloud. One employee, in us-east-1 Region, has created a stack 'Application1' and made an exported output with the name 'ELBDNSName'. Another employee has created a stack for a different application 'Application2' in us-east-2 Region and also exported an output with the name 'ELBDNSName'. The first employee wanted to deploy the CloudFormation stack 'Application1' in us-east-2, but it got an error. What is the cause of the error?

"Exported Output Values in CloudFormation must have unique names within a single Region"

Using CloudFormation, you can create a template that describes all the AWS resources that you want (like Amazon EC2 instances or Amazon RDS DB instances), and AWS CloudFormation takes care of provisioning and configuring those resources for you.

A CloudFormation template has an optional Outputs section which declares output values that you can import into other stacks (to create cross-stack references), return in response (to describe stack calls), or view on the AWS CloudFormation console. For example, you can output the S3 bucket name for a stack to make the bucket easier to find.

You can use the Export Output Values to export the name of the resource output for a cross-stack reference. For each AWS account, export names must be unique within a region. In this case, we would have a conflict within us-east-2.

The development team has just configured and attached the IAM policy needed to access AWS Billing and Cost Management for all users under the Finance department. But, the users are unable to see AWS Billing and Cost Management service in the AWS console.

What could be the reason for this issue?

You need to activate IAM user access to the Billing and Cost Management console for all the users who need access - By default, IAM users do not have access to the AWS Billing and Cost Management console. You or your account administrator must grant users access. You can do this by activating IAM user access to the Billing and Cost Management console and attaching an IAM policy to your users. Then, you need to activate IAM user access for IAM policies to take effect. You only need to activate IAM user access once.

As part of his development work, an AWS Certified Developer Associate is creating policies and attaching them to IAM identities. After creating necessary Identity-based policies, he is now creating Resource-based policies. Which is the only resource-based policy that the IAM service supports?

Trust policy - Trust policies define which principal entities (accounts, users, roles, and federated users) can assume the role. An IAM role is both an identity and a resource that supports resource-based policies. For this reason, you must attach both a trust policy and an identity-based policy to an IAM role. The IAM service supports only one type of resource-based policy called a role trust policy, which is attached to an IAM role.

We manage access in AWS by creating policies and attaching them to IAM identities (users, groups of users, or roles) or AWS resources. A policy is an object in AWS that, when associated with an identity or resource, defines their permissions. Resource-based policies are JSON policy documents that you attach to a resource such as an Amazon S3 bucket. These policies grant the specified principal permission to perform specific actions on that resource and define under what conditions this applies.

When running a Rolling deployment in Elastic Beanstalk environment, only two batches completed the deployment successfully, while rest of the batches failed to deploy the updated version. Following this, the development team terminated the instances from the failed deployment.What will be the status of these failed instances post termination?

Elastic Beanstalk will replace them with instances running the application version from the most recent successful deployment

When processing a batch, Elastic Beanstalk detaches all instances in the batch from the load balancer, deploys the new application version, and then reattaches the instances. If you enable connection draining, Elastic Beanstalk drains existing connections from the Amazon EC2 instances in each batch before beginning the deployment.

If a deployment fails after one or more batches completed successfully, the completed batches run the new version of your application while any pending batches continue to run the old version. You can identify the version running on the instances in your environment on the health page in the console. This page displays the deployment ID of the most recent deployment that was executed on each instance in your environment. If you terminate instances from the failed deployment, Elastic Beanstalk replaces them with instances running the application version from the most recent successful deployment.

An application is hosted by a 3rd party and exposed at yourapp.3rdparty.com. You would like to have your users access your application using www.mydomain.com, which you own and manage under Route 53.What Route 53 record should you create?

Create a CNAME record

A CNAME record maps DNS queries for the name of the current record, such as acme.example.com, to another domain (example.com or example.net) or subdomain (acme.example.com or zenith.example.org).

CNAME records can be used to map one domain name to another. Although you should keep in mind that the DNS protocol does not allow you to create a CNAME record for the top node of a DNS namespace, also known as the zone apex. For example, if you register the DNS name example.com, the zone apex is example.com. You cannot create a CNAME record for example.com, but you can create CNAME records for www.example.com, newproduct.example.com, and so on.

You're a developer working on a large scale order processing application. After developing the features, you commit your code to AWS CodeCommit and begin building the project with AWS CodeBuild before it gets deployed to the server. The build is taking too long and the error points to an issue resolving dependencies from a third-party. You would like to prevent a build running this long in the future for similar underlying reasons.

Which of the following options represents the best solution to address this use-case?

Enable CodeBuild timeouts

A build represents a set of actions performed by AWS CodeBuild to create output artifacts (for example, a JAR file) based on a set of input artifacts (for example, a collection of Java class files).

The following rules apply when you run multiple builds:

When possible, builds run concurrently. The maximum number of concurrently running builds can vary.

Builds are queued if the number of concurrently running builds reaches its limit. The maximum number of builds in a queue is five times the concurrent build limit.

A build in a queue that does not start after the number of minutes specified in its time out value is removed from the queue. The default timeout value is eight hours. We can override the build queue timeout with a value between five minutes and eight hours when you run your build.By setting the timeout configuration, the build process will automatically terminate post the expiry of the configured timeout.

A firm runs its technology operations on a fleet of Amazon EC2 instances. The firm needs a certain software to be available on the instances to support their daily workflows. The developer team has been told to use the user data feature of EC2 instances.Which of the following are true about the user data EC2 configuration? 

User Data is generally used to perform common automated configuration tasks and even run scripts after the instance starts. When you launch an instance in Amazon EC2, you can pass two types of user data - shell scripts and cloud-init directives. You can also pass this data into the launch wizard as plain text or as a file.

By default, scripts entered as user data are executed with root user privileges - Scripts entered as user data are executed as the root user, hence do not need the sudo command in the script. Any files you create will be owned by root; if you need non-root users to have file access, you should modify the permissions accordingly in the script.

By default, user data runs only during the boot cycle when you first launch an instance - By default, user data scripts and cloud-init directives run only during the boot cycle when you first launch an instance. You can update your configuration to ensure that your user data scripts and cloud-init directives run every time you restart your instance.

A multi-national company has just moved to AWS Cloud and it has configured forecast-based AWS Budgets alerts for cost management. However, no alerts have been received even though the account and the budgets have been created almost three weeks ago.What could be the issue with the AWS Budgets configuration?

AWS Budgets lets customers set custom budgets and receive alerts if their costs or usage exceed (or are forecasted to exceed) their budgeted amount.

AWS requires approximately 5 weeks of usage data to generate budget forecasts - AWS requires approximately 5 weeks of usage data to generate budget forecasts. If you set a budget to alert based on a forecasted amount, this budget alert isn't triggered until you have enough historical usage information.