Ansible with Terraform run playbook against one of multiple hosts-CodePudding

My end goal is to create a 3 node kubeadm kubernetes cluster with terraform and/or ansible. As of now I am provisioning three identical instances with terraform. Then with remote-exec and inline installing packages that all instances share between themselves. Now I want to install specific packages only on one of those three instances. Trying to achieve this using local-exec.

I am struggling with connecting only to 1 instance with local-exec. I know how to connect to all of them and execute playbook against three instances. But the end goal is to connect to one instance only.

the code snipped:

resource "aws_instance" "r100c96" {
  count              = 3
  ami                = "ami-0b9064170e32bde34" 
  instance_type      = "t2.micro"
  key_name           = local.key_name

  tags = {
    Name = "terra-ans${count.index}"
  }

  provisioner "remote-exec" {
    connection {
      host        = "${self.public_ip}"
      type        = "ssh"
      user        = local.ssh_user
      private_key = file(local.private_key_path)  
    }
    inline = ["sudo hostnamectl set-hostname test"]
  }


  provisioner "local-exec" {
   
    command = "ansible-playbook  -i ${element((aws_instance.r100c96.*.public_ip),0)}, --private-key ${local.private_key_path} helm.yaml"

  }
...
}

Thanks,

CodePudding user response：

I think instead of * use the count.index, on every loop run it will pass the specific VM IP.

Also, there are multiple ways to provision a VM using Ansible. Consider if you can dynamically build your Hosts file and provision them in parallel instead one at a time.

CodePudding user response：

You can use null_resource, and and run your remote-exec for selected instance only, once all three instances in aws_instance.r100c96 are provisioned.