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Difficulty: HardDeployment Strategies and Execution

A company hosts a high-traffic web application on AWS Elastic Beanstalk. A SysOps Administrator must configure a deployment strategy for an upcoming application update that satisfies the following operational requirements:

1. The application must maintain 100%100\% of its serving capacity throughout the deployment process.
2. The rollback process must be immediate and automated if the new version fails post-deployment health checks.
3. The strategy must not rely on DNS routing changes or CNAME swaps, as downstream client applications cache DNS records with long Time to Live (TTL) values.

Which deployment strategy should the SysOps Administrator select to meet these requirements?

  1. Immutable deploymentAnswer
  2. B
    Rolling with additional batch deployment
  3. C
    Blue/Green deployment
  4. D
    Rolling deployment

Answer

Immutable deployment
The correct option is the one specifying an Immutable deployment. An Immutable deployment launches a temporary Auto Scaling group with the new version alongside the existing one. This satisfies the 100%100\% capacity requirement because the old instances remain fully operational. Traffic is shifted to the new instances within the same environment, avoiding any DNS or CNAME modifications. If post-deployment health checks fail, Elastic Beanstalk terminates the temporary Auto Scaling group, immediately returning the environment to its original state.

Step-by-Step Solution

1
Evaluate the capacity requirement.
Standard rolling deployments are eliminated because they reduce active instance capacity during updates. Rolling with additional batch, Immutable, and Blue/Green deployments all preserve capacity.
The scenario requires maintaining 100%100\% serving capacity at all times.
2
Evaluate the rollback and DNS requirements.
Blue/Green deployments are eliminated because they rely on DNS CNAME swaps, which violate the constraint against DNS routing changes due to long client-side TTL caching.
DNS-based switchovers are slow to propagate if clients cache old records.
3
Compare the remaining strategies (Immutable vs. Rolling with additional batch) on rollback performance.
Immutable deployments are selected. Rolling with additional batch updates existing instances in-place, which requires a slow batch-by-batch redeployment of the old version to roll back. Immutable deployments run on a temporary Auto Scaling group that can be instantly terminated if health checks fail, resulting in an immediate rollback.
Only Immutable deployments offer clean, immediate rollbacks without in-place modification of existing resources.

Key Concept

Selecting and configuring AWS Elastic Beanstalk deployment policies to meet capacity, rollback speed, and DNS routing constraints.
Estimated Time:2m 0s
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Topics

Deployment Strategies and Execution

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