Terraform v0.12.0 Using variables dynamically in resources hack until we get for_each. Only works for sets of 2 as implemented.

0.12.0.tf

variable "nodes" {
  type = map(object({
    size  = string
    count = number
  }))
  default = {
    manager = {
      size  = "s-1vcpu-1gb"
      count = 1
    }
    worker = {
      size  = "s-1vcpu-1gb"
      count = 1
    }
  }
}

locals {
  node_keys = keys(var.nodes)
}

resource "digitalocean_droplet" "node" {
  count = var.nodes.manager.count + var.nodes.worker.count

  name = format("%s-node-%s-%s-%02d", var.project,
    (count.index < var.nodes.manager.count ? node_keys[0] : node_keys[1]),
    var.region,
    count.index + 1 - (count.index < var.nodes.manager.count ? 0 : var.nodes.manager.count),
  )

  size = (count.index < var.nodes.manager.count ? var.nodes.manager.size : var.nodes.worker.size)
  # ...
}

future.tf

variable "nodes" {
  type = map(object({
    size  = string
    count = number
  }))
  default = {
    manager = {
      count = 1
      size  = "s-1vcpu-1gb"
    }
    worker = {
      count = 1
      size  = "s-1vcpu-1gb"
    }
  }
}

resource "digitalocean_droplet" "node" {
  for_each = var.nodes
  count    = each.value.count
  name     = format("%s-node-%s-%s-%02d", var.project, each.key, var.region, count.index + 1)
  size     = each.value.size
  # ...
}