Terraform : count, for_each

Count :

resource "aws_instance" "www" {
  ami                         = "ami-8ee056f3"
  instance_type               = "t2.micro"
  key_name                    = "aws-ssh-key"
  count                       = 2
  tags = {
    Name = "www${count.index}"
  }
}

For_Each :

locals {
  volumes = toset([
    "data",
    "backup",
  ])
}

resource "aws_ebs_volume" "vol" {
  for_each          = local.volumes
  availability_zone = "us-west-2a"
  size              = 10
  tags = {
    Name = "Volume ${each.key}"
  }

}