Dynamic blocks involving data sources

Terraform
1

specifically using the vsphere provider as documented here:
was wondering how to implement multiple network stanzas when involving a datasource:

ref: https://www.terraform.io/docs/providers/vsphere/r/virtual_machine.html

specifically:

...
data "vsphere_network" "network" {
  name          = "var.networks.label"
  datacenter_id = "${data.vsphere_datacenter.dc.id}"
}
...
resource "vsphere_virtual_machine" "vm" {
...
  network_interface {
     network_id = "${data.vsphere_network.network.id}"
  }
}
...

I’d like to do replace network_interface with something like

  dynamic "network_interface" {
    for_each = [for s in var.networks: {
        networkid = networks.label
    }]
    content {
       networkid = network_interface.networkid
    }
}

But I need to somehow get the data source to work across the array of hashes -

variable "networks" { default = [
   {label = "foo"},
   {label = "bar"}
   ]
}

I hope this is a good explanation of what I am trying to do with my psuedo code attempt.

2

Hi @rismoney!

What you’ve shared so far seems to be on the right track, as far as I can tell. Did you get some specific error when you tried that? If you could share it, we can hopefully suggest how to address that error.

I think I am probably missing a detail here because it’s not clear to me how the second example relates to the data source in the first example. I think seeing how Terraform behaved when you tried this would help to understand what I’m missing.

3

It’s not a question of an error (yet). My question is with regard to the data source.
How can I have the datasource iterate through the list map.

In typing this up, I need to have the value for
network_id = "${data.vsphere_network.network.id}"
not the networks.label value.

4

If I’m understanding correctly what you want to achieve, I think the following should do it:

variable "networks" {
  type = list(object({
    label = string
  }))
}

data "vsphere_network" "network" {
  count = length(var.networks)

  name          = var.networks[count.index].label
  datacenter_id = data.vsphere_datacenter.dc.id
}

resource "vsphere_virtual_machine" "vm" {
  # ...

  dynamic "network_interface" {
    for_each = data.vsphere_network.network
    content {
      networkid = network_interface.value.id
    }
  }
}

The key is to use multiple instances of the data resource, with one instance per network you want to connect with, and then generate a network_interface block for each of those instances.

2 Likes
5

Yes that is absolutely what I was trying to achieve. I will give it a try. I didn’t realize I can do count on data source and peg it against the size of the list

6

This works great, but now I’m struggling to assign IPs and Netmasks to those networks inside the clone block. Say i have these 2 variable lists:

vsphere_virtual_machine_ipv4_address = [ "172.23.32.115", "172.23.64.200",]
vsphere_virtual_machine_ipv4_mask    = [ "20", "20" ]

And i want to dynamically assign it to the the N interfaces i created:

clone {
  template_uuid = data.vsphere_virtual_machine.template.id

    customize {
      linux_options {
        host_name = var.vsphere_virtual_machine_name
        domain    = var.vsphere_virtual_machine_domain
    }
    dynamic "network_interface" {
     for_each      =  var.vsphere_virtual_machine_ipv4_address
     content  {
      ipv4_address = var.vsphere_virtual_machine_ipv4_address
      ipv4_netmask = var. vsphere_virtual_machine_ipv4_mask
      }
    }

     ipv4_gateway    = var.vsphere_virtual_machine_ipv4_gateway
     dns_server_list = var.vsphere_virtual_machine_dns_list
     dns_suffix_list = var.vsphere_virtual_machine_suffix_list
   }
 }

But i’m not able to iterate over the “vsphere_virtual_machine_ipv4_address” list. I tried using indexes and attributes but it’s not working either.

7

Need some help on how to get the secrets from Azure key vault using dynamic blocks. Searched around and also saw the documentation, couldnt find my help.

I have the below code to retrieve secrets. But it is repeating for each secret to be retrieved and if a key vault has a different set of secrets to retrieve then i have to define them in a separate tf file. Rather i would like to pass the secret names as vars to a tf file which would iterate the list of vars and build the data blocks using dynamic blocks. Is there an option to do this in terraform 0.12 now?

main.tf

data “azurerm_key_vault_secret” “secret1” {
name = “secret1”
key_vault_id = “/subscriptions/{var.subscription_id}/resourceGroups/{var.kvsecrets_rg_name}/providers/Microsoft.KeyVault/vaults/{var.kv_name}" } data "azurerm_key_vault_secret" "secret2" { name = "secret2" key_vault_id = "/subscriptions/{var.subscription_id}/resourceGroups/{var.kvsecrets_rg_name}/providers/Microsoft.KeyVault/vaults/{var.kv_name}”
}

output.tf

output “secret1” {
sensitive = true
value = “${data.azurerm_key_vault_secret.secret1.value}”
}

output “secret2” {
sensitive = true
value = “${data.azurerm_key_vault_secret.secret2.value}”
}

8

Have you managed anything since then?
There’s a network_interface block also inside linux_options, but that cannot be solved through a dynamic block. Which renders the whole dynamic block for network_interfaces completely useless, because defining only one interface inside the clone will error out :slight_smile:

The number of network adapter settings in the customization specification: 1 does not match the number of network adapters present in the virtual machine: 2.