serverless-multi-regions

This plugin will add the resources to configure API Gateway regional endpoints and a global endpoint with CloudFront.

This plugin will:

Set up API Gateways for your lambdas in each region
Set up a custom domain in each region for the API Gateway and specify the appropriate base path
Set up a basic HTTPS healthcheck for the API in each region
Set up Route 53 for failover based routing with failover between regions based on the healthcheck created
Set up CloudFormation in front of Route 53 failover with TLS 1.2 specified
Set up Route 53 with the desired domain name in front of CloudFront

Install plugin:

npm install serverless-multi-regions --save-dev

Create your hosted zone and certificates

Using the diagram above as an example the hosted zone would be for example.com and the certificate would be for *.example.com. Create the same certificate in each region to support the regional endpoints. The global endpoint requires a certificate in the us-east-1 region.

serverless.yml:

plugins:
  - serverless-multi-regions

# Add this to the standard SLS "custom" region
custom:
  # The API Gateway method CloudFormation LogicalID to await. Defaults to ApiGatewayMethodProxyVarAny.
  # Aspects of the templates must await this completion to be created properly.
  gatewayMethodDependency: ApiGatewayMethodProxyVarAny

  # Settings used for API Gateway and Route 53
  dns:
    domainName: ${self:service}.example.com
    # Explicity specify the regional domain name.
    # This must be unique per stage but must be the same in each region for failover to function properly
    regionalDomainName: ${self:custom.dns.domainName}-${opt:stage}
    # Specify the resource path for the healthcheck (only applicable if you don't specify a healthcheckId below)
    # the default is /${opt:stage}/healthcheck
    healthCheckResourcePath: /${opt:stage}/healthcheck
    # Settings per region for API Gateway and Route 53
    us-east-1:
      # Specify a certificate by its ARN
      acmCertificateArn: arn:aws:acm:us-east-1:870671212434:certificate/55555555-5555-5555-5555-5555555555555555
      # Use your own healthcheck by it's ID
      healthCheckId: 44444444-4444-4444-4444-444444444444
      # Failover type (if not present, defaults to Latency based failover)
      failover: PRIMARY
    ap-northeast-1:
      acmCertificateArn: arn:aws:acm:ap-northeast-1:111111111111:certificate/55555555-5555-5555-5555-5555555555555555
      healthCheckId: 33333333-3333-3333-3333-333333333333
      failover: SECONDARY

  # Settings used for CloudFront
  cdn:
    # Indicates which CloudFormation region deployment used to provision CloudFront (because you only need to provision CloudFront once)
    region: us-east-1
    # Aliases registered in CloudFront
    # If aliases is not present, the domain name is set up as an alias by default.
    # If *no* aliases are desired, leave an empty aliases section here.
    aliases:
      - ${self:custom.dns.domainName}
    # Add any headers your CloudFront requires here
    headers:
      - Accept
      - Accept-Encoding
      - Authorization
      - User-Agent
      - X-Forwarded-For
    # Specify a price class, PriceClass_100 is the default
    priceClass: PriceClass_100
    # Specify your certificate explicitly by the ARN
    # If the certificate is not specified, the best match certificate to the domain name is used by default
    acmCertificateArn: ${self:custom.dns.us-east-1.acmCertificateArn}
    # Set up logging for CloudFront
    logging:
      bucket: example-auditing.s3.amazonaws.com
      prefix: aws-cloudfront/api/${opt:stage}/${self:service}
    # Add the webACLId to your CloudFront
    webACLId: id-for-your-webacl

Deploy to each region

You've got your configuration all set.

Now perform a serverless deployment to each region you want your Lambda to operate in. The items you have specified above are set up appropriately for each region and non-regional resources such as CloudFront and Route 53 are also set up via CloudFormation in your primary region.

You now have a Lambda API with cross-region failover!!!