libvirt: Use custom storage pool

Don't assume `default` storage pool and create a new custom one.

Fixes openshift#1457.

data/data/libvirt/bootstrap/main.tf

@@ -1,11 +1,13 @@
 resource "libvirt_volume" "bootstrap" {
   name           = "${var.cluster_id}-bootstrap"
   base_volume_id = var.base_volume_id
+  pool           = var.pool
 }
 
 resource "libvirt_ignition" "bootstrap" {
   name    = "${var.cluster_id}-bootstrap.ign"
   content = var.ignition
+  pool    = var.pool
 }
 
 resource "libvirt_domain" "bootstrap" {

data/data/libvirt/bootstrap/variables.tf

@@ -24,3 +24,7 @@ variable "network_id" {
   description = "The ID of a network resource containing the bootstrap node's addresses."
 }
 
+variable "pool" {
+  type        = string
+  description = "The name of the storage pool."
+}

data/data/libvirt/main.tf

@@ -2,11 +2,18 @@ provider "libvirt" {
   uri = var.libvirt_uri
 }
 
+resource "libvirt_pool" "storage_pool" {
+  name = var.cluster_id
+  type = "dir"
+  path = "/var/lib/libvirt/images/${var.cluster_id}"
+}
+
 module "volume" {
   source = "./volume"
 
   cluster_id = var.cluster_id
   image      = var.os_image
+  pool       = libvirt_pool.storage_pool.name
 }
 
 module "bootstrap" {
@@ -17,17 +24,20 @@ module "bootstrap" {
   cluster_id     = var.cluster_id
   ignition       = var.ignition_bootstrap
   network_id     = libvirt_network.net.id
+  pool           = libvirt_pool.storage_pool.name
 }
 
 resource "libvirt_volume" "master" {
   count          = var.master_count
   name           = "${var.cluster_id}-master-${count.index}"
   base_volume_id = module.volume.coreos_base_volume_id
+  pool           = libvirt_pool.storage_pool.name
 }
 
 resource "libvirt_ignition" "master" {
   name    = "${var.cluster_id}-master.ign"
   content = var.ignition_master
+  pool    = libvirt_pool.storage_pool.name
 }
 
 resource "libvirt_network" "net" {

data/data/libvirt/volume/main.tf

@@ -1,5 +1,5 @@
 resource "libvirt_volume" "coreos_base" {
   name   = "${var.cluster_id}-base"
   source = var.image
+  pool   = var.pool
 }
-

data/data/libvirt/volume/variables.tf

@@ -8,3 +8,7 @@ variable "image" {
   type        = string
 }
 
+variable "pool" {
+  type        = string
+  description = "The name of the storage pool."
+}

pkg/asset/machines/libvirt/machines.go

@@ -69,7 +69,7 @@ func provider(clusterID string, networkInterfaceAddress string, platform *libvir
 			UserDataSecret: userDataSecret,
 		},
 		Volume: &libvirtprovider.Volume{
-			PoolName:     "default",
+			PoolName:     clusterID,
 			BaseVolumeID: fmt.Sprintf("%s-base", clusterID),
 		},
 		NetworkInterfaceName:    clusterID,