1

I'm using terraform with the libvirt provider and generate 4 guests (index: 0,1,2,3) using this snippet:

[...]
resource "libvirt_domain" "worker" {
    count   = var.worker["count"]
    name    = "${var.cluster_id}-worker-${count.index}"
    memory  = var.worker.memory
    vcpu    = var.worker.vcpu

    coreos_ignition = libvirt_ignition.worker[count.index].id

    disk {
        volume_id = libvirt_volume.worker[count.index].id
    }
    console {
        type        = "pty"
        target_port = 0
    }
    cpu = {
        mode = var.cpu_mode
    }
    network_interface {
        network_id  = var.network_id
        hostname    = "worker-${count.index}.${var.cluster_id}.${var.cluster_domain}"
        mac         = var.worker_macs[count.index]
    }
}
[...]

Now I want to add a conditional statement, that the first two workers get GPUs assigned. So in python pseudo code sth. like

if ${count.index} == 0:
    # Add GPU 0 to worker ${count.index} (--> worker0)
elif ${count.index} == 1:
    # Add GPU 1 to worker ${count.index} (--> worker1)
else:
    # Don't assign a GPU to a worker

From the libvirt provider documentation I saw that I have to use XML and xslt which I already checked with a simpler script and that works.

Now I tried it in this more complex setup with conditional statements as well as dynamic blocks but I cannot get it working. Currently it looks like this:

resource "libvirt_domain" "worker" {
    count   = var.worker["count"]
    name    = "${var.cluster_id}-worker-${count.index}"
    memory  = var.worker.memory
    vcpu    = var.worker.vcpu

    coreos_ignition = libvirt_ignition.worker[count.index].id

    disk {
        volume_id = libvirt_volume.worker[count.index].id
    }
    console {
        type        = "pty"
        target_port = 0
    }
    cpu = {
        mode = var.cpu_mode
    }
    network_interface {
        network_id  = var.network_id
        hostname    = "worker-${count.index}.${var.cluster_id}.${var.cluster_domain}"
        mac         = var.worker_macs[count.index]
    }

    dynamic "xml" {
        for_each = var.worker
        content {
            xslt = file("add_gpu_w${count.index}.xsl")
        }
    }
}

I feel like dynamic blocks might be the wrong approach because it is looping through all workers, but I also didn't get it working with the conditional statement appraoch.

Any help is appreciated - thanks!

4

1 回答 1

1

这当然是一个有趣的案例，是的，我认为动态块可以做你需要的，我们只需要一个条件，比如：

  dynamic "xml" {
    for_each = count.index < 2 ? ["1"]: []
    content {
      xslt = file("add_gpu_w${count.index}.xsl")
    }
  }

该代码的关键是：
count.index < 2 ? ["1"]: []

只是索引上的一个条件，对于 0 和 1，我们给出一个包含一个元素的数组，其他所有内容都得到一个空数组，这应该绕过 GPU 的分配。

于 2021-12-01T14:41:31.837 回答