serverless-load-balancer

serverless framework sample that shows how to deploy a load balancer (with vpc/subnet configuration) connected to a lambda in aws.

• creates a LoadBalancer, HTTP Listener and Lambda
• links the Listener and Lambda
• stores the LoadBalancerDNSName (url) in ParameterStore

This feature has been introduced in v 1.45 and extended in 1.46 serverless framework

• see changelog

when to use load balancer instead of api gateway ?

• https://serverless-training.com/articles/save-money-by-replacing-api-gateway-with-application-load-balancer/
• https://serverless-training.com/articles/api-gateway-vs-application-load-balancer-technical-details/

Install Requirements

npm install serverless -g
npm install

Modify Config

Modify the file /config/serverless.config.yml

• VPC / Subnet configuration for load balancer
• Scheme for load balancer (see aws documentation)

    VPC_ID: 'vpc-xxxxxxxxx'
    SUBNET_ID_A: "subnet-xxxxxxxxx"
    SUBNET_ID_B: "subnet-xxxxxxxxx"
    SUBNET_ID_C: "subnet-xxxxxxxxx"
    SCHEME: "internet-facing" or "internal" # load balancer scheme - 

Deploy solution

sls deploy

Result:

1. Execute info to get load balancer url

sls info -v

you should get the full output containing the load balancer url.

Stack Outputs
LoadBalancerDNSName: serverless-load-balancer-258977035.eu-central-1.elb.amazonaws.com
HandlerLambdaFunctionQualifiedArn: arn:aws:lambda:eu-central-1:368555349508:function:serverless-load-balancer-dev-handler:1
ServerlessDeploymentBucketName: serverless-load-balancer-serverlessdeploymentbuck-16pgpyls1225e

2. Paste the LoadBalancerDNSName Value into your browser or execute postman to set a GET statement against the URL.

Expected Response:

    Successfully executed lambda call via loadbalancer

Additional things to know

• This sample does not care if the lambda and the load balancer are both in a vpc. It could be mixed in anyway dependent of the use case

• The load balancer url will be stored as Parameter in Parameter store. This helps to reference the loadbalancer url easily tool-independent in other stacks.