SOA-C03 practice question: Deployment strategies and third-party tools (1 of 2)

Deployment, Provisioning, and Automation A free question from our original SOA-C03 practice exam. Try it, then open the answer to see why each option is right or wrong.

A dental chain's booking application runs in an AWS Elastic Beanstalk environment with 12 instances. Rolling deployments reduce capacity during busy hours, and when a bad version was released last month, rolling back took 40 minutes. The chain wants deployments that keep full capacity, put no new code on existing instances, and allow a fast rollback by simply removing new instances. The environment's URL and DNS must not change. Which deployment policy should a CloudOps engineer choose?

Choose one answer.

A. All at once, so that the new version reaches every instance together and the deployment finishes as quickly as possible.
B. Rolling with additional batch, so that a new batch of instances is launched first and capacity stays full during deployment.
C. Immutable, so that the new version goes to new instances in a temporary Auto Scaling group.
D. Blue/green with a CNAME swap, so that the new version runs in a separate environment before traffic moves to it.

Show the answer and explanation

Answer: C

A. Wrong: All at once deploys to the existing instances at the same time, which causes a short outage. A bad version would also need a full redeployment to roll back. Learn more: Deployment policies and settings (opens in a new tab)
B. Wrong: This keeps full capacity, but it still deploys the new version onto existing instances batch by batch. A rollback means another rolling deployment. Learn more: Deployment policies and settings (opens in a new tab)
C. Right: Correct. Immutable deployments launch a full set of new instances alongside the old ones and move them in only when they pass health checks. Rolling back means terminating the new instances, and the environment's URL stays the same. Learn more: Deployment policies and settings (opens in a new tab)
D. Wrong: A CNAME swap keeps capacity and allows a quick swap back, but it changes which environment the DNS name points to. The chain requires the URL and DNS to stay unchanged. Learn more: Blue/Green deployments with Elastic Beanstalk (opens in a new tab)

Explanation

Elastic Beanstalk offers several deployment policies. Immutable deployments never change existing instances, keep full capacity and make rollback a matter of terminating the new instances, all inside the same environment. Blue/green also gives quick rollback, but it relies on swapping the environment's CNAME.

SOA-C03 practice question: Deployment strategies and third-party tools (1 of 2)

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