Lambda Versioning and Alias Traffic Shifting — CLI Sequence

• A.Run the update-function-code command again with the --publish flag.
• B.Run the delete-function command and then create-function with the updated code.
• ✓ C.Run the publish-version command to create a new version from the updated $LATEST.
• D.Run the update-function-configuration command to set the version number.

Why C: Option C is correct because the `update-function-code` command without the `--publish` flag only updates the `$LATEST` version of the Lambda function. To create an immutable, numbered version that preserves the previous code, the developer must explicitly run the `publish-version` command, which takes the current `$LATEST` code and publishes it as a new version (e.g., version 2). This ensures the previous version (version 1) remains unchanged and can be referenced via its version ARN.

• A.aws lambda publish-version --function-name my-function
• B.aws lambda create-function --function-name my-function --zip-file fileb://my-code.zip
• ✓ C.aws lambda update-alias --function-name my-function --name prod --function-version 2 --routing-config AdditionalVersionWeights={"1":0.9}
• D.aws lambda invoke --function-name my-function --payload '{}'

Why C: Option C is correct because the `update-alias` command with the `--routing-config` parameter allows you to implement canary deployments by assigning a percentage of traffic to a new Lambda function version. In this case, `AdditionalVersionWeights={"1":0.9}` routes 10% of traffic to version 2 (the new version) and 90% to version 1. However, note that this command only sets a static routing configuration; to gradually increase traffic to 100% over 10 minutes, you must update the alias multiple times (e.g., via a script) to adjust the weights progressively. The command shown is the correct initial step to start the canary deployment.

• ✓ A.aws lambda publish-version --function-name my-function
• B.aws lambda update-function-configuration --function-name my-function --handler new-handler
• C.aws lambda update-function-code --function-name my-function --zip-file fileb://my-code.zip
• D.aws lambda create-function --function-name my-function --zip-file fileb://my-code.zip

Why A: Option A is correct because the `aws lambda publish-version` command creates an immutable, versioned snapshot of the Lambda function's code and configuration, which is required for production-ready deployments. This ensures the old version remains available for rollback while the new version is published with a unique version number (e.g., $LATEST, 1, 2). The command explicitly publishes the current $LATEST version as a new numbered version, making it production-ready without affecting existing versions.

• A.Update the function code using update-function-code.
• ✓ B.Use a weighted alias to gradually shift traffic to a new version.
• ✓ C.Create a new version and update the alias to point to the new version.
• D.Create a new Lambda function and delete the old one.
• E.Update the function configuration to increase memory.

Why B: Option B is correct because a weighted alias allows you to route a small percentage of traffic to a new Lambda version while keeping the majority on the current version, enabling canary deployments with zero downtime. Option C is correct because creating a new version and updating the alias to point to it performs an instant, atomic switch, ensuring all traffic is served by the new version without any interruption.