Terraform Provision

Provision in Terraform

If you need to do some initial setup on your instances, then provisioners let you upload files, run shell scripts, or install and trigger other software like configuration management tools, etc.

Defining a Provisioner

provider "aws" {
 access_key = "AXXXXX"
 secret_key = "XXXXXX"
 region = "us-east-2"
}

resource "aws_instance" "Feenix_test" {
 ami = "ami-0cd3dfa4e37921605"
 instance_type = "t2.micro"
  tags {
    name = "feenix_web"
    }
  provisioner "local-exec" {
   command = "echo ${aws_instance.Feenix_test.public_ip} > public-ip.txt"
  }
 }

This adds a provisioner block within the resource block. Multiple provisioner blocks can be added to define multiple provisioning steps.
Terraform supports multiple provisioners, but for this example, we are using the local-exec provisioner.

Running Provisioners

C:\Users\bnarayan\terraform>terraform apply

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  + aws_instance.Feenix_test
      id:                           <computed>
      ami:                          "ami-0cd3dfa4e37921605"
      arn:                          <computed>
.
.

aws_instance.Feenix_test: Provisioning with 'local-exec'...
aws_instance.Feenix_test (local-exec): Executing: ["cmd" "/C" "echo 3.19.30.122 > public-ip.txt"]
aws_instance.Feenix_test: Creation complete after 59s (ID: i-01b6a6e957358ecf1)

we can see IP address stored in the file.

C:\Users\bnarayan\terraform>type public-ip.txt
3.19.30.122