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Difficulty: HardDeployment Strategies

A developer is configuring an in-place deployment in AWS CodeDeploy for an application running on a fleet of 1212 Amazon EC2 instances. To prevent performance degradation during peak hours, the application must maintain at least 75%75\% of its serving capacity online and healthy at all times during the update. The developer wants to configure the deployment to update the maximum number of instances simultaneously while strictly adhering to this availability constraint. Which configuration should the developer use?

  1. Create a custom deployment configuration with Minimum Healthy Hosts defined as a type of FLEET_PERCENT with a value of 7575.Answer
  2. B
    Create a custom deployment configuration with Minimum Healthy Hosts defined as a type of HOST_COUNT with a value of 33.
  3. C
    Use the predefined CodeDeployDefault.HalfAtATime deployment configuration.
  4. D
    Use the predefined CodeDeployDefault.OneAtATime deployment configuration.

Answer

Create a custom deployment configuration with Minimum Healthy Hosts defined as a type of FLEET_PERCENT with a value of 7575.
The correct option ensures that 75%75\% of the instance capacity (99 instances) remains healthy and online during the deployment. This allows CodeDeploy to update the remaining 33 instances (25%25\%) in parallel, completing the deployment as quickly as possible without violating the availability threshold.

Step-by-Step Solution

1
Calculate the minimum number of healthy instances required.
At least 99 instances must remain online (12×0.75=912 \times 0.75 = 9).
This establishes the target capacity baseline that cannot be breached during the rolling update.
2
Evaluate the maximum number of instances that can be updated simultaneously.
A maximum of 33 instances can be updated at any given time (12−9=312 - 9 = 3).
To complete the deployment as fast as possible, CodeDeploy should update the maximum allowable instances (33) in each batch.
3
Determine the type and value for the Minimum Healthy Hosts parameter.
Set Minimum Healthy Hosts to a type of FLEET_PERCENT with a value of 7575 (or HOST_COUNT with a value of 99).
Using FLEET_PERCENT with 75%75\% ensures that 99 instances remain online. The predefined configurations (such as HalfAtATime) or setting HOST_COUNT to 33 would violate the constraint or deploy slower than necessary.

Key Concept

Custom deployment configurations in AWS CodeDeploy allow developers to define availability requirements using the Minimum Healthy Hosts parameter, specified as either a percentage or absolute host count.
Estimated Time:2m 0s
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Topics

Deployment Strategies

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