route53-register

This is a CloudFormation stack which includes a Lambda function and a CloudWatch event to create/delete A record when launching/terminating EC2 instance.

Required tools

You need to install following tools before develop and deploy this CloudFormation stack.

• aws-sam-cli
  • Run function locally, validate CloudFormation configuration and deploy.
• jq
• Jsonnet
  • CloudFormation configuration is written in Jsonnet for templating and make it simple.

Required environment variables

Common

• DLQ_NAME: A name of DLQ to send a message when an invocation of function is failed.
• DNS_SUFFIX: A suffix of DNS record.
  • If this value is .apne1.aws.example.com and launched instance name is foo-001, an A record foo-001.apne1.aws.example.com will be registered.
• HOSTED_ZONE_ID: A Hosted zone ID manipulated by this function.
• LAMBDA_ROLE: A role ARN to attach this function.
  • You should allow following IAM actions to the role.
    • route53:ChangeResourceRecordSets
    • ec2:DescribeInstances
    • sqs:SendMessage
      • Need to send a message to a dead letter queue.

Only development

• TEST_INSTANCE_ID: An instance ID for testing. This ID is used to emulate CloudWatch Events and an A record is determined by the instance Name tag. Therefore, you need to specify actual EC2 instance ID.

Only packaging and deploy

• SAM_ARTIFACT_BUCKET: A S3 bucket to put an artifact.
• STACK_NAME: A CloudFormation stack name you want to create.

Development

This project uses a Docker image provided by LambCI because make an environment building binary same as running environment.

Therefore, you should create a Docker image before develop and deploy.

make init

After changing code, you can build a debug binary and run the Lambda function locally with following make tasks.

make build
make run-create-record # Emulate launching an EC2 instance
make run-delete-record # Emulate terminating and EC2 instance

Package and deploy

You can build a release binary and package it with CloudFormation template. That is a simple wrapper to generate CloudFormation configuration from Jsonnet template and execute sam validate, sam package and sam deploy commands.

make release-build
make package
make plan # This task shows a changeset. It can fail when the CloudFormation stack is not created yet.
make deploy

Generated CloudFormation configuration will create a Lambda function and a CloudWatch event invoking the function.

License

MIT