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Difficulty: MediumAWS Elastic Beanstalk

An e-commerce company runs a production web application on AWS Elastic Beanstalk. The application is deployed across 1010 Amazon EC2 instances inside an Auto Scaling group behind an Application Load Balancer. A developer needs to configure a deployment strategy for a minor application update. The deployment must satisfy the following constraints:

* The environment must maintain exactly 100%100\% of its capacity (1010 instances) to handle traffic at all times during the update.
* The temporary cost overhead during the deployment process must be kept to a minimum.
* The update must be performed within the existing environment without creating a new environment or swapping CNAMEs.

Which Elastic Beanstalk deployment policy should the developer select?

  1. A
    All at once
  2. B
    Rolling
  3. Rolling with additional batchAnswer
  4. D
    Immutable

Answer

Rolling with additional batch
The deployment policy that meets all criteria is the one that adds an additional batch of instances before taking any offline, thereby maintaining the full environment capacity of ten instances during deployment. Since only one batch is provisioned at a time, the temporary cost overhead is minimized. Furthermore, the deployment is executed entirely within the existing environment.

Step-by-Step Solution

1
Evaluate the capacity constraint.
Since the application must maintain 100%100\% capacity (1010 instances) during the update, the policies 'All at once' and 'Rolling' are ruled out because they take instances out of service.
Eliminating options that reduce capacity helps narrow down choices to policies that add temporary instances.
2
Evaluate the cost overhead constraint.
Between 'Immutable' and 'Rolling with additional batch', the 'Rolling with additional batch' policy is more cost-efficient because it only launches a small, configurable batch of extra instances (e.g., 11 or 22), whereas 'Immutable' launches a duplicate set of 1010 instances (doubling the cost).
Comparing temporary cost resource provisioning determines the most cost-effective solution.
3
Evaluate the environment constraint.
The 'Rolling with additional batch' policy performs the update in-place within the existing Auto Scaling group and environment, avoiding CNAME swapping.
Ensures alignment with all environmental limits.

Key Concept

AWS Elastic Beanstalk deployment policies and their tradeoffs regarding capacity, deployment speed, rollback, and cost.
Estimated Time:1m 30s
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Topics

AWS Elastic Beanstalk

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