Support attaching pre-existing volumes to node groups (#998)

* support attaching pre-existing volumes to node groups and output IDs to
inventory

* fix tf lint errors

Author: sjpb

environments/site/tofu/inventory.tpl

@@ -29,6 +29,7 @@ ${cluster_name}_${group_name}:
             networks: ${jsonencode({for n in node.network: n.name => {"fixed_ip_v4": n.fixed_ip_v4, "fixed_ip_v6": n.fixed_ip_v6}})}
             node_fqdn: ${login_groups[group_name]["fqdns"][nodename]}
             node_fip: ${login_groups[group_name]["nodegroup_fips"][nodename]}
+            volumes: ${jsonencode(try(login_groups[group_name]["volumes"][nodename], {}))}
 %{ endfor ~}
 
 ${group_name}:
@@ -53,6 +54,7 @@ ${cluster_name}_${group_name}:
             instance_id: ${ node.id }
             networks: ${jsonencode({for n in node.network: n.name => {"fixed_ip_v4": n.fixed_ip_v4, "fixed_ip_v6": n.fixed_ip_v6}})}
             node_fqdn: ${compute_groups[group_name]["fqdns"][nodename]}
+            volumes: ${jsonencode(try(compute_groups[group_name]["volumes"][nodename], {}))}
 %{ endfor ~}
     vars:
         # NB: this is the target image, not necessarily what is provisioned

environments/site/tofu/node_group/nodes.tf

@@ -9,6 +9,8 @@ locals {
   # this is a mapping with
   # keys "compute-0-vol-a", "compute-0-vol-b" ...
   # values which are a mapping e.g. {"node"="compute-0", "volume"="vol-a"}
+  all_compute_volume_ids = { for k, v in local.all_compute_volumes : k => try(openstack_blockstorage_volume_v3.compute[k].id, data.openstack_blockstorage_volume_v3.compute[k].id) }
+
 
   # Workaround for lifecycle meta-argument only taking static values
   compute_instances = var.ignore_image_changes ? openstack_compute_instance_v2.compute_fixed_image : openstack_compute_instance_v2.compute
@@ -34,9 +36,14 @@ locals {
   baremetal_az = var.availability_zone != null ? var.availability_zone : "nova"
 }
 
+data "openstack_blockstorage_volume_v3" "compute" {
+  for_each = { for k, v in local.all_compute_volumes : k => v if var.extra_volumes[v.volume].size == null }
+  name     = "${var.cluster_name}-${each.key}"
+}
+
 resource "openstack_blockstorage_volume_v3" "compute" {
 
-  for_each = local.all_compute_volumes
+  for_each = { for k, v in local.all_compute_volumes : k => v if var.extra_volumes[v.volume].size != null }
 
   name        = "${var.cluster_name}-${each.key}"
   description = "Compute node ${each.value.node} volume ${each.value.volume}"
@@ -49,7 +56,7 @@ resource "openstack_compute_volume_attach_v2" "compute" {
   for_each = local.all_compute_volumes
 
   instance_id = local.compute_instances[each.value.node].id
-  volume_id   = openstack_blockstorage_volume_v3.compute[each.key].id
+  volume_id   = local.all_compute_volume_ids[each.key]
 }
 
 resource "openstack_networking_port_v2" "compute" {
@@ -238,3 +245,7 @@ output "fqdns" {
 output "nodegroup_fips" {
   value = local.nodegroup_fips
 }
+
+output "volumes" {
+  value = { for nn in var.nodes : nn => { for vn, vv in var.extra_volumes : vn => local.all_compute_volume_ids["${nn}-${vn}"] } }
+}

environments/site/tofu/node_group/variables.tf

@@ -65,7 +65,7 @@ variable "extra_volumes" {
         EOF
   type = map(
     object({
-      size        = number
+      size        = optional(number)
       volume_type = optional(string)
     })
   )

environments/site/tofu/variables.tf

@@ -65,12 +65,15 @@ variable "login" {
       vnic_types: Overrides variable vnic_types
       volume_backed_instances: Overrides variable volume_backed_instances
       root_volume_size: Overrides variable root_volume_size
-      extra_volumes: Mapping defining additional volumes to create and attach
-                     Keys are unique volume name.
-                     Values are a mapping with:
-                          size: Size of volume in GB
-                          volume_type: Optional. Type of volume, or cloud default
-                     **NB**: The order in /dev is not guaranteed to match the mapping
+      extra_volumes: Mapping defining additional volumes. Keys are a unique volume
+                     name. Values are a mapping with:
+                      - size: Optional. Size of volume to create in GB.
+                      - volume_type: Optional. Type of volume, or cloud default.
+                     If size is not given then a volume `cluster_name-node-volume_key`
+                     must already exist, where `node` is an entry in this group's
+                     `nodes` parameter. Such volumes will not be managed by the
+                     appliance.
+                     **NB**: The order in /dev is not guaranteed to match the mapping.
       fip_addresses: List of addresses of floating IPs to associate with
                      nodes, in the same order as nodes parameter. The
                      floating IPs must already be allocated to the project.
@@ -136,12 +139,15 @@ variable "compute" {
       ignore_image_changes: Ignore changes to the image_id parameter (see docs/experimental/compute-init.md)
       volume_backed_instances: Overrides variable volume_backed_instances
       root_volume_size: Overrides variable root_volume_size
-      extra_volumes: Mapping defining additional volumes to create and attach
-                     Keys are unique volume name.
-                     Values are a mapping with:
-                          size: Size of volume in GB
-                          volume_type: Optional. Type of volume, or cloud default
-                     **NB**: The order in /dev is not guaranteed to match the mapping
+      extra_volumes: Mapping defining additional volumes. Keys are a unique volume
+                     name. Values are a mapping with:
+                      - size: Optional. Size of volume to create in GB.
+                      - volume_type: Optional. Type of volume, or cloud default.
+                     If size is not given then a volume `cluster_name-node-volume_key`
+                     must already exist, where `node` is an entry in this group's
+                     `nodes` parameter. Such volumes will not be managed by the
+                     appliance.
+                     **NB**: The order in /dev is not guaranteed to match the mapping.
       ip_addresses: Mapping of list of fixed IP addresses for nodes, keyed
                     by network name, in same order as nodes parameter.
                     For any networks not specified here the cloud will