SOA-C03 practice question: Deployment strategies and third-party tools (2 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 pet insurer releases new versions of its premium-calculation AWS Lambda function with AWS CodeDeploy. Last week, a faulty version reached all users at once and returned errors for 20 minutes before anyone noticed. The team wants each new version to receive a small share of traffic first, and the deployment to roll back automatically if errors rise, without human action. Which TWO changes should a CloudOps engineer make? (Choose two.)

Choose two answers.

A. Point a Route 53 weighted record at the old and new function versions, and adjust the weights by hand during each release.
B. Publish each new version and have clients call the version number directly, so that the team can change it back if errors appear.
C. Use the CodeDeployDefault.LambdaCanary10Percent5Minutes deployment configuration for the function's deployment group.
D. Use the CodeDeployDefault.LambdaAllAtOnce deployment configuration and lower the function's reserved concurrency during deployments.
E. Add a CloudWatch alarm on the function's error metric to the deployment group and turn on rollback when an alarm threshold is met.

Show the answer and explanation

Answers: C, E

A. Wrong: Lambda versions are not DNS endpoints, and manual weight changes need human action. Traffic shifting between Lambda versions is done with alias routing, which CodeDeploy manages. Learn more: Weighted routing (opens in a new tab)
B. Wrong: Calling versions directly moves all clients at once and makes rollback a manual change in every client. Aliases exist so that clients keep one stable name. Learn more: Lambda function aliases (opens in a new tab)
C. Right: Correct. This configuration shifts 10 percent of traffic on the alias to the new version, waits five minutes, then shifts the rest. A faulty version reaches only a small share of users first. Learn more: Working with deployment configurations in CodeDeploy (opens in a new tab)
D. Wrong: All at once sends every request to the new version immediately, which is what caused last week's outage. Reserved concurrency limits capacity rather than limiting exposure to a bad version. Learn more: Working with deployment configurations in CodeDeploy (opens in a new tab)
E. Right: Correct. CodeDeploy watches the alarms attached to a deployment group. If an alarm goes into ALARM during the deployment, CodeDeploy stops it and shifts traffic back to the previous version. Learn more: Monitoring deployments with CloudWatch alarms in CodeDeploy (opens in a new tab)

Explanation

CodeDeploy shifts traffic between Lambda versions through an alias. A canary configuration sends a small share of traffic to the new version first, and CloudWatch alarms attached to the deployment group trigger automatic rollback when errors rise. Together they limit the impact of a bad release without anyone watching.

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

Explanation

Study

Keep practicing