I’m currently trying to create several instances under Openstack with Terraform. Afterwards I want to attach more of them. But I’m not getting anywhere with the last point. Does anyone have an idea how I can solve it?
variable "instances" {
description = "The Instances to be deployed"
type = map(object({
name = string
image = string
flavor = string
volume_size = number
security_groups = list(string)
network = string
keypair_name = string
floating_ip_pool = string
tags = list(string)
additional_disks = list(object({
disk = string
volume_size = number
}))
}))
}
instances = {
"Websrv01" = {
name = "websrv01"
image = "Ubuntu 22.04"
flavor = "SCS-2V-4-20s"
volume_size = 20
security_groups = ["default"]
network = "test-intern"
keypair_name = "ssh-pub"
floating_ip_pool = "public"
tags = ["general", "webserver"]
additional_disks = []
},
"dbsrv01" = {
name = "dbsrv01"
image = "Ubuntu 22.04"
flavor = "SCS-2V-4-20s"
volume_size = 20
security_groups = ["default"]
network = "test-intern"
keypair_name = "ssh-pub"
floating_ip_pool = "public"
tags = ["general", "dbserver"]
additional_disks = [
{ disk = "db_data", volume_size = 30 },
{ disk = "db_log", volume_size = 10 }
]
}
}
resource "openstack_compute_instance_v2" "instances" {
for_each = var.instances
name = each.value.name
flavor_id = data.openstack_compute_flavor_v2.flavor[each.key].id
key_pair = each.value.keypair_name
security_groups = each.value.security_groups
## Boot Disk
block_device {
uuid = data.openstack_images_image_v2.image[each.key].id
source_type = "image"
volume_size = each.value.volume_size
boot_index = 0
destination_type = "volume"
delete_on_termination = true
}
lifecycle {
prevent_destroy = true
network {
name = each.value.network
}
tags = each.value.tags
}
## Get floating IP if needed
resource "openstack_networking_floatingip_v2" "floating_ip" {
for_each = { for k, v in var.instances : k => v if v.floating_ip_pool != "" }
pool = each.value.floating_ip_pool
}
## Associate floating ip to Instances
resource "openstack_compute_floatingip_associate_v2" "associate" {
for_each = openstack_networking_floatingip_v2.floating_ip
instance_id = openstack_compute_instance_v2.instances[each.key].id
floating_ip = each.value.address
}
## Additional Disks
resource "openstack_blockstorage_volume_v3" "additional_disks" {
for_each = {
for instance, disks in var.instances : instance => disks.additional_disks
if length(disks.additional_disks) > 0
}
name = "${each.key}-${each.value[0].disk}"
size = each.value[0].volume_size
enable_online_resize = true
}
## Attach additional disks to instances
resource "openstack_compute_volume_attach_v2" "attach_additional_disks" {
for_each = {
for instance, disks in var.instances : instance => disks.additional_disks
if length(disks.additional_disks) > 0
}
instance_id = openstack_compute_instance_v2.instances[each.key].id
volume_id = openstack_blockstorage_volume_v3.additional_disks[each.key].id
}
Only the first hard disk is taken into account here. Ich i try to loop truth the list, with [*] it fails.
regards Eddi
with single addition Disk it works:
resource "openstack_blockstorage_volume_v3" "additional_disks" {
for_each = {
for instance, disks in var.instances : instance => disks.additional_disks
if length(disks.additional_disks) > 0
}
name = "${each.key}-${each.value[0].disk}"
size = each.value[0].volume_size
enable_online_resize = true
}
resource "openstack_compute_volume_attach_v2" "attach_additional_disks" {
for_each = {
for instance, disks in var.instances : instance => disks.additional_disks
if length(disks.additional_disks) > 0
}
instance_id = openstack_compute_instance_v2.instances[each.key].id
volume_id = openstack_blockstorage_volume_v3.additional_disks[each.key].id
}
I had already tried to solve it with ChatGPT. And he was already on the right track. But had not suggested a solution with locals. Had tried it in the for_each loop using flatten. I am not yet familiar with flatten and locals. Now I have changed the solution a bit, in a simpler notation, after ChatGPT had suggested to convert to a map(object).
This is what my solution looks like now:
variable "instances" {
description = "The Instances to be deployed"
type = map(object({
name = string
image = string
flavor = string
volume_size = number
security_groups = list(string)
network = string
keypair_name = string
floating_ip_pool = string
tags = list(string)
additional_disks = map(object({
volume_size = number
}))
}))
}
instances = {
"Websrv01" = {
name = "websrv01"
image = "Ubuntu 22.04"
flavor = "SCS-2V-4-20s"
volume_size = 20
security_groups = ["default"]
network = "test-intern"
keypair_name = "ssh_general"
floating_ip_pool = "public"
tags = ["general", "webserver"]
additional_disks = {}
},
"Websrv02" = {
name = "websrv02"
image = "Ubuntu 22.04"
flavor = "SCS-2V-4-20s"
volume_size = 20
security_groups = ["default"]
network = "test-intern"
keypair_name = "ssh_general"
floating_ip_pool = "public"
tags = ["general", "webserver"]
additional_disks = {}
},
"dbsrv01" = {
name = "dbsrv01"
image = "Ubuntu 22.04"
flavor = "SCS-2V-4-20s"
volume_size = 20
security_groups = ["default"]
network = "test-intern"
keypair_name = "ssh_general"
floating_ip_pool = "public"
tags = ["general", "dbserver"]
additional_disks = {
db_data = { volume_size = 30 },
db_log = { volume_size = 10 }
}
}
}
## create a flatten structure vom var.instances
locals {
additional_disks = flatten([
for instance_key, instance in var.instances : [
for disk_name, disk in instance.additional_disks : {
instance_key = instance_key
disk_name = disk_name
disk_values = disk
}
]
])
}
## Create Additional Disks for Instances
resource "openstack_blockstorage_volume_v3" "additional_disks" {
for_each = {
for disk in local.additional_disks : "${disk.instance_key}-${disk.disk_name}" => disk
}
name = each.key
size = each.value.disk_values.volume_size
enable_online_resize = true
}
## Attach additional disks to instances
resource "openstack_compute_volume_attach_v2" "attach_additional_disks" {
for_each = {
for disk in local.additional_disks : "${disk.instance_key}-${disk.disk_name}" => disk
}
instance_id = openstack_compute_instance_v2.instances[each.value.instance_key].id
volume_id = openstack_blockstorage_volume_v3.additional_disks[each.key].id
}
I will also implement the tip with enable_online_resize.
Another question. I would like to use the code in several environments, so it will certainly make sense to create a module from it? Then I'll give it a try now.
And finally, I would like to generate a dynamic inventory in INI format for Ansible and group it with the tags. Are there any easy ways to do this?