Commit multi-AZ Terraform configurations

Commit a set of Terraform configurations that support multi-AZ deployments

Signed-off-by: Scott Lowe <scott.lowe@scottlowe.org>

terraform/aws/vpc-all-azs/compute.tf

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+# Launch instances across subnets/AZs
+resource "aws_instance" "node" {
+    count                   = "${var.num_nodes}"
+    ami                     = "${data.aws_ami.node_ami.id}"
+    instance_type           = "${var.node_type}"
+    key_name                = "${var.key_pair}"
+    vpc_security_group_ids  = ["${aws_vpc.demo_vpc.default_security_group_id}"]
+    subnet_id               = "${element(aws_subnet.demo_subnet.*.id, count.index)}"
+    tags {
+        Name                = "node-${count.index}"
+        tool                = "terraform"
+        demo                = "terraform"
+        area                = "compute"
+    }
+}

terraform/aws/vpc-all-azs/data.tf

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+data "aws_availability_zones" "avail_zones" {
+    state                   = "available"
+}
+
+data "aws_ami" "node_ami" {
+    most_recent             = true
+    owners                  = ["099720109477"]
+    filter {
+        name                = "name"
+        values              = ["*ubuntu-xenial-16.04*"]
+    }
+    filter {
+        name                = "virtualization-type"
+        values              = ["hvm"]
+    }
+    filter {
+        name                = "root-device-type"
+        values              = ["ebs"]
+    }
+}

terraform/aws/vpc-all-azs/networking.tf

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+# Create a new VPC
+resource "aws_vpc" "demo_vpc" {
+    cidr_block              = "${var.assigned_cidr}"
+    enable_dns_hostnames    = "true"
+    enable_dns_support      = "true"
+    tags {
+        Name                = "multi_az_vpc"
+        tool                = "terraform"
+        demo                = "terraform"
+        area                = "networking"
+    }
+}
+
+# Modify default security group to allow inbound SSH
+resource "aws_security_group_rule" "allow_ssh" {
+    type                    = "ingress"
+    from_port               = 22
+    to_port                 = 22
+    protocol                = "tcp"
+    cidr_blocks             = ["0.0.0.0/0"]
+    security_group_id       = "${aws_vpc.demo_vpc.default_security_group_id}"
+}
+
+# Create a new Internet gateway
+resource "aws_internet_gateway" "demo_gw" {
+    vpc_id                  = "${aws_vpc.demo_vpc.id}"
+    tags {
+        Name                = "multi_az_gw"
+        tool                = "terraform"
+        demo                = "terraform"
+        area                = "networking"
+    }
+}
+
+# Add default route to VPC's main route table
+resource "aws_route" "default" {
+    route_table_id          = "${aws_vpc.demo_vpc.main_route_table_id}"
+    destination_cidr_block  = "0.0.0.0/0"
+    gateway_id              = "${aws_internet_gateway.demo_gw.id}"
+}
+
+# Create public subnet(s) in the new VPC
+resource "aws_subnet" "demo_subnet" {
+    count                   = "${length(data.aws_availability_zones.avail_zones.names)}"
+    vpc_id                  = "${aws_vpc.demo_vpc.id}"
+    cidr_block              = "${cidrsubnet(var.assigned_cidr, 8, count.index)}"
+    availability_zone       = "${element(data.aws_availability_zones.avail_zones.names, count.index)}"
+    map_public_ip_on_launch = "true"
+    tags {
+        Name                = "demo_subnet_${count.index}"
+        tool                = "terraform"
+        demo                = "terraform"
+        area                = "networking"
+    }
+}

terraform/aws/vpc-all-azs/provider.tf

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+provider "aws" {
+    region                  = "${var.user_region}"
+}

terraform/aws/vpc-all-azs/variables.tf

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+variable "user_region" {
+    type                    = "string"
+    description             = "AWS region to use for new resources"
+}
+
+variable "assigned_cidr" {
+    type                    = "string"
+    description             = "CIDR block to use for VPC and subnets"
+}
+
+variable "node_type" {
+    type                    = "string"
+    description             = "Type of instance to launch (such as t2.micro)"
+}
+
+variable "key_pair" {
+    type                    = "string"
+    description             = "SSH keypair to inject into launched instances"
+}
+
+variable "num_nodes" {
+    type                    = "string"
+    description             = "Number of nodes to launch"
+}