Serverless Plugin Canary Deployments
npm i --save-dev serverless-plugin-canary-deployments
To enable gradual deployments for Lambda functions, your
serverless.yml should look like this:
service: canary-deployments provider: name: aws runtime: nodejs6.10 iamRoleStatements: - Effect: Allow Action: - codedeploy:* Resource: - "*" plugins: - serverless-plugin-canary-deployments functions: hello: handler: handler.hello events: - http: GET hello deploymentSettings: type: Linear10PercentEvery1Minute alias: Live preTrafficHook: preHook postTrafficHook: postHook alarms: - FooAlarm # When a string is provided, it expects the alarm Logical ID - name: BarAlarm # When an object is provided, it expects the alarm name in the name property preHook: handler: hooks.pre postHook: handler: hooks.post
You can see a working example in the example folder.
type: (required) defines how the traffic will be shifted between Lambda function versions. It must be one of the following:
Canary10Percent5Minutes: shifts 10 percent of traffic in the first increment. The remaining 90 percent is deployed five minutes later.
Canary10Percent10Minutes: shifts 10 percent of traffic in the first increment. The remaining 90 percent is deployed 10 minutes later.
Canary10Percent15Minutes: shifts 10 percent of traffic in the first increment. The remaining 90 percent is deployed 15 minutes later.
Canary10Percent30Minutes: shifts 10 percent of traffic in the first increment. The remaining 90 percent is deployed 30 minutes later.
Linear10PercentEvery1Minute: shifts 10 percent of traffic every minute until all traffic is shifted.
Linear10PercentEvery2Minutes: shifts 10 percent of traffic every two minutes until all traffic is shifted.
Linear10PercentEvery3Minutes: shifts 10 percent of traffic every three minutes until all traffic is shifted.
Linear10PercentEvery10Minutes: shifts 10 percent of traffic every 30 minutes until all traffic is shifted.
alias: (required) name that will be used to create the Lambda function alias.
preTrafficHook: (optional) validation Lambda function that runs before traffic shifting. It must use te CodeDeploy SDK to notify about this step's success or failure (more info here).
postTrafficHook: (optional) validation Lambda function that runs after traffic shifting. It must use te CodeDeploy SDK to notify about this step's success or failure (more info here)
alarms: (optional) list of CloudWatch alarms. If any of them is triggered duringt the deployment, the associated Lambda function will automatically roll back to the previous version.
You can set default values for all functions in a top-level custom deploymentSettings section. E.g.:
custom: deploymentSettings: codeDeployRole: some_arn_value stages: - dev - prod functions: ...
Some values are only available as top-level configurations. They are:
codeDeployRole: (optional) an ARN specifying an existing IAM role for CodeDeploy. If absent, one will be created for you. See the codeDeploy policy for an example of what is needed.
stages: (optional) list of stages where you want to deploy your functions gradually. If not present, it assumes that are all of them.
How it works
The plugin relies on the AWS Lambda traffic shifting feature to balance traffic between versions and AWS CodeDeploy to automatically update its weight. It modifies the
CloudFormation template generated by Serverless, so that:
- It creates a Lambda function Alias for each function with deployment settings.
- It creates a CodeDeploy Application and adds a CodeDeploy DeploymentGroup per Lambda function, according to the specified settings.
- It modifies events that trigger Lambda functions, so that they invoke the newly created alias.
For now, the plugin only works with Lambda functions invoked by API Gateway, Stream based (such as the triggered by Kinesis or DynamoDB Streams), SNS based events and S3 events. More events will be added soon.
ISC © David García