I'm trying to deploy two virtual machines within the same resource group to our Azure platform with Terraform. After successfully creating the first one Terraform then wants to destroy the first one to create the second one after I've changed the second VM name and Azure tag.
I've been following the Terraform guide: https://www.terraform.io/docs/providers/azurerm/r/virtual_machine.html
resource "azurerm_virtual_machine" "main" {
location = "${var.location}"
name = "${var.vm_name}"
network_interface_ids = ["${azurerm_network_interface.main.id}"]
resource_group_name = "${var.resourcegroup_vm}"
vm_size = "${var.vm_size}"
tags {
application = "${var.tag}"
}
I expected Terraform to just create the second VM after changing its variable name and tag. Not wanting to destory the first one because of the name and tag change.
Terraform is based on HCL (Hashicorp Configuration Language), which is the format *.tf files are written in. It is a declarative language (as opposed to imperative), which means that you describe the desired state you want your infrastructure to be and Terraform will figure out what changes are needed to take it to that point.
If you first create an instance and then change its name you are telling Terraform that you no longer want your instance to have the old name but the new one.
To deploy a number of instances you can use the count attribute. You could then use interpolation to get names and tags based in the counter, something similar to this:
resource "azurerm_virtual_machine" "main" {
location = "${var.location}"
name = "${var.vm_name}-${count.index + 1}"
network_interface_ids = ["${azurerm_network_interface.main.id}"]
resource_group_name = "${var.resourcegroup_vm}"
vm_size = "${var.vm_size}"
tags {
application = "${var.tag}-${count.index + 1}"
}
count = 2
}
Note the attached -${count.index + 1} to name and the application tag.
Related
Is it possible to skip 1 argument for 1 workspace in terraform?
resource "azurerm_application_gateway" "appgw" {
name = var.appgw
resource_group_name = var.resource_group
location = var.location
**zones = var.aks_zones**
sku {
name = var.app_gateway_sku
tier = var.app_gateway_tier
}
I am setting a DR environment in a region where availability zones are not supported, so for the script to pass the "Zones" argument needs to be skipped for one workspace only. Is this possible?
To fix this, I added an availability_zone = "No-Zone" argument to my AppGW IP address block.
Since the azurerm_application_gateway resource's zones variable is Optional (source), you can set the default value for your aks_zones variable to null:
variable "aks_zones" {
default = null
}
This way, you can skip specifying the aks_zones variable for your one workspace while setting a value for the other workspaces.
I need to get a list of all VM ids in an Azure subscription using Terraform then read them back one by one and feed one id at a time to a module to perform some tasks on it, how can i do this?
You can use the feature multiple instances of the data source to get the list of all the VM ids. See the data source azurerm_virtual_machine, it requires the name and the resource group name. So if the VMs in the same group, you just need to create a list variable for all the VM names, then the data block will be like this:
variable "vm_names" {
type = list(string)
default = [
...
]
}
data "azurerm_virtual_machine" "example" {
count = length(var.vm_names)
name = element(var.vm_names, count.index)
resource_group_name = var.resource_group_name
}
output "vm_ids" {
value = data.azurerm_virtual_machine.example.*.id
}
The output is all the VM ids.
I am new to Terraform, using Azure...I am trying to build a module "compute" where I can deploy a single vm or a vm set.
For a single VM I need a network interface, a security group association, and a azurerm_linux_virtual_machine. For a vm set I need to provision only azurerm_linux_virtual_machine_scale_set. Is it possible to pass a boolean variable to this module to select which resources get executed?
I've checked this post but apparently there is no such thing.
Should I simply divide the module into compute/vm and compute/scale_set and actually have two modules, one for single vms and one for vm sets? Not sure if this will be a pain to maintain in the future.
Yes, you can use a boolean to select what is built. Generally speaking, you can use the count control:
resource "azurerm_linux_virtual_machine" "vm" {
count = var.single_only ? 1 : 0
... (rest of config)
}
resource "azurerm_linux_virtual_machine_scale_set" "vm_set" {
count = var.single_only ? 0 : 1
... (rest of config)
}
(see the end of this section on count resources)
Yes, it's possible and you don't need to divide the module.
As the statements in the posted link:
You can accomplish the resource creating selection by using the count parameter and conditional expression.
In this case, you can declare two bool variables like this:
variable "create_vm" {
description = "If set to true, it will create vm"
type = bool
}
variable "create_vmss" {
description = "If set to true, it will create vmss"
type = bool
}
and define the resource azurerm_linux_virtual_machine and azurerm_linux_virtual_machine_scale_set in the same VM module.
resource "azurerm_linux_virtual_machine" "example" {
count = var.create_vm ? 1 : 0
name = "example-machine"
resource_group_name = azurerm_resource_group.example.name
location = azurerm_resource_group.example.location
size = "Standard_F2"
...
resource "azurerm_linux_virtual_machine_scale_set" "example" {
count = var.create_vmss ? 1 : 0
name = "example-vmss"
resource_group_name = azurerm_resource_group.example.name
location = azurerm_resource_group.example.location
sku = "Standard_F2"
instances = 1
admin_username = "adminuser"
....
Then call the submodule like this,
module "vm" {
source = "./modules/vm"
create_vm = true
create_vmss = false
...
}
Hope this helps.
In my terraform script, I have
resource "azuread_application" "main" {
count = "${length(var.sp_names)}"
name = "${sp_prefix}-${var.sp_names[count.index]}"
available_to_other_tenants = false
}
resource "azuread_service_principal" "main" {
count = "${length(var.sp_names)}"
application_id = "${azuread_application.main.["${sp_prefix}"-"${var.sp_names[count.index]}"].application_id}"
}
when I ran terraform init I get the following error:
An attribute name is required after a dot.
what is the right way to use nested variables and a list object?
In order for a resource to be represented as a map of instances rather than a list of instances, you need to use for_each instead of count:
resource "azuread_application" "main" {
for_each = { for n in var.sp_names : n => "${var.sp_prefix}-${n}" }
name = each.value
available_to_other_tenants = false
}
The for_each expression above is a for expression that transforms your list or set of names into a mapping from the given names to the prefixed names. In the other expressions in that block, each.key would therefore produce the original given name and each.value the prefixed name.
You can then similarly use for_each to declare the intent "create one service principal per application" by using the application resource's map itself as the for_each expression for the service principal resource:
resource "azuread_service_principal" "main" {
for_each = azuread_application.main
application_id = each.value.application_id
}
In this case, the azuread_application.main value is a map from unprefixed names to objects representing each of the declared applications. Therefore each.key in this block is the unprefixed name again, but each.value is the corresponding application object from which we can access the application_id value.
If your var.sp_names had a string "example" in it, then Terraform would interpret the above as a request to create two objects named azuread_application.main["example"] and azuread_service_principal.main["example"], identifying these instances by the var.sp_names values. This is different to count where the instances would have addresses like azuread_application.main[0] and azuread_service_principal.main[0]. By using for_each, we ensure that adding and removing items from var.sp_names will add and remove corresponding instances from those resources, rather than updating existing ones that happen to share the same numeric indices.
I am assuming you are using a version older that 0.12.x. If not the answer from Martin is the best one.
You need to leverage the splatting.
resource "azuread_service_principal" "main" {
count = "${length(var.sp_names)}"
application_id = "${azuread_application.main.*.application_id}"
}
In Terraform, I want to create a route table for an existing subnet. To achieve the desired end result, I need to pull the CIDR/Prefix for the VNET. The VNET CIDR value is not known beforehand, the only values I know before launch is the VNET's name and Resource Group.
I would like to take the VNET CIDR/Prefix and insert it as a destination in the route table.
data "azurerm_virtual_network" "vnet" {
name = "${var.vnet_name}"
resource_group_name = "${var.vnet_rg}"
}
module "routetable" {
source = "modules/routetable"
route_table_name = "${var.route_table_name}"
resource_group_name =
"${data.azurerm_resource_group.vnet.name}"
location = "eastus"
route_prefixes = ["0.0.0.0/0", "${EXISTING_VNET_CIDR_HERE}"]
route_nexthop_types = ["VirtualAppliance", "VirtualAppliance"]
route_names = ["route1", "route2"]
}
just use data you are getting from the vnet:
${data.azurerm_virtual_network.vnet.address_spaces}
the only issue - assress_spaces is an array (i think its called list in terraforms terms).