Building an Autodiscovering Apache Zookeeper Cluster in AWS using Packer, Ansible and Terraform

Following my pattern of building AMIs for applications, I create my Apache Zookeeper cluster with Packer for my AMI and Terraform for the infrastructure. This Zookeeper cluster is auto-discovering of the other nodes that are determined to be in the cluster ###Building Zookeeper AMIs with Packer The packer template looks as follows: { "variables": { "ami_id": "", "private_subnet_id": "", "security_group_id": "", "packer_build_number": "", }, "description": "Zookeeper Image", "builders": [ { "ami_name": "zookeeper-{{user `packer_build_number`}}", "availability_zone": "eu-west-1a", "iam_instance_profile": "app-server", "instance_type": "t2.