Rancher Server Terraform module

This is a terraform module to create a Rancher server on AWS. It is designed to work with host instances placed in autoscaling groups (see my hosts module) and handles (via a sidekick app) automatically deregistering hosts from the server on scale down.

The server is placed behind an Nginx proxy which is responsible for SSL termination.

Features

• Automatic SSL provided by Lets Encrypt
• Stateless server container through the use of an external database
• Includes a sidekick app for automatically removing hosts due to be terminated by an autoscaling group (via autoscaling lifecycle hooks)
• Mostly configurable with variables (happy to accept PRs for new vars)

TODO - jsamuel1

• Use ALB & CertificateManager for SSL Termination
• remove nginx
• Use Secrets Manager for DB connection passwords
• Use RDS Aurora MySQL Serverless

Example usage

Include the following in your Terraform config:

module "rancher_server" {

    # Import the module from Github
    # It's probably better to fork or clone this repo if you intend to use in production
    # so any future changes dont mess up your existing infrastructure.
    source = "github.com/greensheep/terraform-aws-rancher-server"

    # Set the details of the target VPC
    # Tip: this uses my VPC module: github.com/greensheep/terraform-aws-vpc
    vpc_id                 = "${module.vpc.vpc_id}"
    vpc_region             = "${module.vpc.vpc_region}"
    vpc_private_subnets    = "${module.vpc.vpc_private_subnets}"
    vpc_private_subnet_ids = "${module.vpc.vpc_private_subnet_ids}"

    # Server config
    server_name      = "rancher-server"
    server_hostname  = "rancher-server.yourdomain.tld"
    server_key       = "path/to/key.pub"
    server_subnet_id = "${element(split(",", module.vpc.vpc_public_subnet_ids), 0)}"
    server_version   = "v0.42.0"

    # SSL
    ssl_email = "example@domain.com"

    # Database
    database_address  = "dbhost"
    database_username = "dbuser"
    database_password = "dbpass"

}

Notes

• The rancher server takes a minute or so to start up and longer on initial bootstrap.. give it at least 10 mins after terraform has finished creating all the resources.
• On initial bootstrap, the server will be unprotected.. the first thing you should do is configure access control!
• The hostname should be routable to the server before creating hosts - the best way to do this is with Route53 and a terraform config (see example below).
• The rancher database should already be created (Rancher will bootstrap the tables but wont create the DB, see example below).

Example DNS config

resource "aws_route53_record" "server_hostname" {

    zone_id = "YOUR-HOSTED-ZONE-ID"
    name = "rancher-server.yourdomain.tld"
    type = "A"
    ttl = "30"
    records = [
        "${module.rancher_server.server_public_ip}"
    ]

    lifecycle {
        create_before_destroy = true
    }

}

Example RDS database config

# Subnet groups
resource "aws_db_subnet_group" "default" {
    
    name = "main"
    description = "Database VPC private subnets"
    subnet_ids = [
        "${split(",",module.vpc.vpc_private_subnet_ids)}"
    ]

    lifecycle {
        create_before_destroy = true
    }

}

# Security group
resource "aws_security_group" "db" {
    
    name = "Rancher-Database-SG"
    description = "Allow rancher server to access database server."
    vpc_id = "${module.vpc.vpc_id}"

    # Allow traffic from the rancher server security group
    ingress {
        from_port = 3306
        to_port = 3306
        protocol = "tcp"
        security_groups = [
            "${module.rancher_server.server_security_group_id}"
        ]
    }

    lifecycle {
        create_before_destroy = true
    }

}

# Database instance
resource "aws_db_instance" "default" {

    allocated_storage = 10
    engine = "mysql"
    engine_version = "5.6.23"
    identifier = "rancher-database"
    instance_class = "db.t2.micro"
    final_snapshot_identifier = "rancher-database-final"
    publicly_accessible = false
    db_subnet_group_name = "${aws_db_subnet_group.default.name}"
    vpc_security_group_ids = [
        "${aws_security_group.db.id}"
    ]

    # Database details
    name = "rancherserverdb"
    username = "root"
    password = "password01"

    lifecycle {
        create_before_destroy = true
    }

}