DevOps Classroom Series – 30/May/2020

Terraform Provisioning

• Scenario: You are asked to create a VM in the cloud with the latest version of the application installed gameoflife

• Steps:

  • Create a VM using terraform template
  • Now login into the vm and execute the commands

• As of now we dont know how to login into resources and execute commands and that is what a Terraform Provisioner does.

• For Docs Refer Here

• Workflow of Provisioining in Terraform

  1. Create a resource
  2. Estabish a Connection
  3. Execute Provisioning:

• Steps: Installing game of life on AWS EC2

  • Create an EC2 instance and once ec2 is ready
  • Login and execute the following commands

  # Ubuntu VM is ready
  sudo apt-get update
  sudo apt-get install openjdk-8-jdk -y
  sudo apt-get install tomcat8 -y
  cd /tmp
  wget https://war-jar-files.s3-us-west-2.amazonaws.com/gameoflife.war
  sudo cp /tmp/gameoflife.war /var/lib/tomcat8/webapps
  

  • Navigate to http://<publicip>:8080/gameoflife

• Thinking in Terraform:

  • Terraform can create resources and to provision terraform relies on Built-in Provisioners
    • Chef Provisioner
    • file Provisioner
    • local-exec Provisioner
    • remote-exec Provisioner

Solution for Gameoflife in AWS Ec2

• Create a new directory gameoflife and create
  • provider.tf

  provider "aws" {
  
  }
  

  • main.tf

  resource "aws_instance" "gameoflifeprimary" {
  ami                         = var.ubuntuami
  instance_type               = "t2.micro"
  key_name                    = var.keyname
  security_groups             = var.securitygroups
  associate_public_ip_address = true
  
  
  
  
  provisioner "remote-exec" {
      inline                  = [
          "sudo apt-get update",
          "sleep 5",
          "sudo apt-get install openjdk-8-jdk -y",
          "sleep 5",
          "sudo apt-get install tomcat8 -y",
          "sleep 5",
          "cd /var/lib/tomcat8/webapps",
          "sudo wget https://github.com/GitPracticeRepo/game-of-life/blob/master/gameoflife.war",
          "sleep 5",
          "sudo service tomcat8 restart"
      ]
  
      connection {
          type                = "ssh"
          user                = "ubuntu"
          private_key         = file("./sample.pem")
          host                = aws_instance.gameoflifeprimary.public_ip
      }
      
  }
  
  

}

```
* outputs.tf
```
output "publicip" {
value = aws_instance.gameoflifeprimary.public_ip
}
```

• Now apply terraform to create aws ec2 instance with game of life installed