AWS Lambda Canary Deploy

Publish a new Lambda function version and create a weighted alias to begin routing canary traffic alongside the stable version.

The AWS Lambda Canary Deploy step publishes a new version of your Lambda function and creates or updates a weighted alias to begin splitting traffic between the previous version and the new one. Use it as the first step in a canary stage, followed by one or more Traffic Shift steps to gradually increase traffic to the new version.

---

Before you begin

• A Lambda service with an AwsLambdaFunctionDefinition manifest and an artifact source. Whether you also need an AwsLambdaFunctionAliasDefinition manifest depends on your artifact type:

  • ZIP artifact (S3, Artifactory, Nexus): Alias definition is required. The step reads the alias manifest to determine the alias name and fails without one.

  • ECR container image: Alias definition is not required. The step manages the alias automatically.

  • Go to Lambda services.

• A Lambda infrastructure with an AWS connector and region. Go to Lambda infrastructure.

---

Step YAML

- name: AWS Lambda Canary Deploy
  id: awsLambdaCanaryDeployStep
  template:
    uses: awsLambdaCanaryDeployStep

The step uses no explicit with: inputs — service configuration and infrastructure are resolved automatically from the stage context at runtime.

---

Configure the step

When you add the step to a canary stage, the following sections appear. All values are derived automatically from your service and infrastructure configuration.

Service Configuration

Field	Value	Description
Function Definition	${{serviceOutput.manifests.awsLambdaFunction.paths}}	Path to the function definition manifest resolved from the service. Defines the function name, handler, runtime, memory, and timeout.
Function Alias	${{serviceOutput.manifests.awsLambdaAlias.paths}}	Path to the alias definition manifest. Populated when your service includes an AwsLambdaFunctionAliasDefinition manifest. Required for ZIP artifact canary; empty and unused for ECR image canary.

Infrastructure Configuration

Field	Value	Description
AWS Connector	${{infra.connectorRef}}	The AWS connector resolved from the infrastructure definition. Used to authenticate to Lambda and publish the new version.
AWS Region	${{infra.region}}	The AWS region resolved from the infrastructure definition.

ECR image functions

When your artifact is a container image from ECR, the function definition uses packageType: Image — there is no handler or runtime field. Define functionName and role as service variables. The Function Alias field will be empty; this is expected and the canary deploy step handles alias management automatically.

When your artifact is a ZIP file, define functionName and runtime as service variables and add an alias definition manifest so the step can create the named alias.

---

Step outputs

The following output variables are available for use in downstream Traffic Shift steps.

Output variable	Expression	Description
functionName	<+stage.steps.awsLambdaCanaryDeployStep.output.outputVariables.functionName>	The name of the Lambda function that was deployed. Auto-populates the function_name input on Traffic Shift steps.
version	<+stage.steps.awsLambdaCanaryDeployStep.output.outputVariables.version>	The published version number of the new function. Auto-populates the function_version input on Traffic Shift steps.

---

Advanced settings

• Timeout duration: Maximum time the step is allowed to run before being terminated.

• On failure: Define what happens if the step fails — retry, mark as success, or abort.

• Strategy: Configure a looping strategy to run this step over a list of values.

• Conditional execution: Run this step only when a specified condition is true.

---

Next steps

• Go to AWS Lambda Traffic Shift to configure the step that routes traffic to the new version.

• Go to Lambda canary deployment for the full canary flow walkthrough.