Create instances

Version-able infrastructure with Terraform using AWS as the provider.

Installing terraform in your computer

Visit the downloads page and download the appropriate binary for your system. Unzip the download and place the binary in well known path like /usr/local/bin or$HOME/bin. Type the terraform command to check its working. For more specific instrucions, follow the official guide: Install Terraform

Getting started

We are going to create 3 instances. The first will be for the Consul, Zookeeper, Mesos, and Marathon master daemons. The remaining two will be used as Mesos agents to run our applications.

Lucky for you we've put together a code repository for this tutorial. Feel free to clone it; all the.tf extension files are related to Terraform.

When Terraform is run it first globs all the .tf files, creates a dependency graph of the resources declared, compares that against any state that might exist, and then offers you the ability to create, modify, or detroy the resources defined.

terraform plan will do a dry run of what will be changed to the state of infrastructure if we were to apply our current resource definitions. terraform apply will actually change the state of the infrastructure. Terraform asks for access_key_ and _secret_key when you run plan or apply

variables.tf

Variables like project name, ssh_public_key, instance type, ami (amazon machine image), region, availability_zone, cidr are specified

The AWS access_key _and secret_key _are filled by user for every command execution.

provider.aws is an inbuilt component is responsible for all aws related commands to get executed by terraform

vpc_and_networking.tf

Creates a virtual private network with cidr block

Creates an internet gateway for the vpc that is created earlier

Creates a subnet within the vpc with specified cidr block

Creates a routing table and routing table association for the vpc's gateway

Creates a security group which has all ingress and egress rules used for all instances.

instances.tf

Creates a key in aws ec2 for that region. The key name and ssh public key are from variables.tf

All the above components are used in creating these resources

Logs the public ip for instances created

terraform.tfstate and terraform.tfstate.backup

These are the json files used by terraform to stores the state of infrastructure and understands them too.

Check the AWS web console EC2 tab to see the changes reflected. Play around !