Configure provisioning script for multiple instance VM vSphere deployment - linux

Question

I can't quite work out how to add a provisioning "remote-exec" section to my module, where I would like it to copy configuration scripts from the project directory and execute them. But when I add this module I can't seem to have it target the VM instance and as it has multiple network cards, I would just like to target the primary card.
I have used this to deploy a Linux VM via Terraform on a on-premise vSphere instance.
provider "vsphere" {
user = var.vsphere_user
password = var.vsphere_password
vsphere_server = var.vsphere_server
# If you have a self-signed cert
allow_unverified_ssl = true
}
This is the sample Linux deployment script outlining the network part, which allows configuring of multiple network card to a VM
resource "vsphere_virtual_machine" "Linux" {
count = var.is_windows_image ? 0 : var.instances
depends_on = [var.vm_depends_on]
name = "%{if var.vmnameliteral != ""}${var.vmnameliteral}%{else}${var.vmname}${count.index + 1}${var.vmnamesuffix}%{endif}"
........
dynamic "network_interface" {
for_each = keys(var.network) #data.vsphere_network.network[*].id #other option
content {
network_id = data.vsphere_network.network[network_interface.key].id
adapter_type = var.network_type != null ? var.network_type[network_interface.key] : data.vsphere_virtual_machine.template.network_interface_types[0]
}
}
........
//Copy the file to execute
provisioner "file" {
source = var.provisioner_file_source // eg ./scripts/*
destination = var.provisioner_file_destination // eg /tmp/filename
connection {
type = "ssh" // for Linux its SSH
user = var.provisioner_ssh_username
password = var.provisioner_ssh_password
host = self.vsphere_virtual_machine.Linux.*.guest_ip_address
}
}
//Run the script
provisioner "remote-exec" {
inline = [
"chmod +x ${var.provisioner_file_destination}",
"${var.provisioner_file_destination} args",
]
connection {
type = "ssh" // for Linux its SSH
user = var.provisioner_ssh_username
password = var.provisioner_ssh_password
host = self.vsphere_virtual_machine.Linux.*.guest_ip_address
}
}
}
} // end of resource "vsphere_virtual_machine" "Linux"
So I have tried self. reference but thus far self.vsphere_virtual_machine.Linux.*.guest_ip_address this just shows the entire array of guest IPs?
Anyone able to point me in the right direction or even a good guide on terraform modules?

Answer 1

The first issue I notice is that the vsphere_virtual_machine resource doesn't have a property guest_ip_address, it is guest_ip_addresses. This does indeed return a list, so you would need to figure out how to select the IP you want from the list. I'm not sure if the ordering is predictable in vSphere. If I recall, it isn't.
The simplest approach, without knowing what you're trying to accomplish, would probably be to use the default_ip_address as this returns a single address and selects the ip for the "most likely" scenario.
It looks like you're also setting up the host to be multi-homed. This adds additional complexity. If default_ip_address doesn't give you what you want, you'll need to resort to using some more complex expression to find your IP. Perhaps you could use the sort function so the ordering is more predictable. You may also be able to "find" the IP using a for loop.
Regarding building modules, if the above code is in a module, the first thing I would recommend is avoiding the use of count. Reasoning for this is explained in the following texts. Hashicorp has a lot of good documentation directly on their site. Also, the folks over at gruntwork also have a blog series that they developed into a book called Terraform Up and Running. I recommend checking this out.