kvm: Allow to use a device (/dev/...) as disk

software/kvm/instance-kvm.cfg.jinja2

@@ -91,6 +91,7 @@ tap-interface = ${slap-network-information:network-interface}
 disk-size = ${slap-parameter:disk-size}
 disk-type = ${slap-parameter:disk-type}
 disk-format = ${slap-parameter:disk-format}
+disk-device-path = ${slap-parameter:disk-device-path}
 disk-path = ${directory:srv}/virtual.${slap-parameter:disk-format}
 
 pid-file-path = ${kvm-controller-parameter-dict:pid-file}
@@ -565,6 +566,8 @@ ram-max-size = 51200
 ram-hotplug-slot-size = 512
 disk-size = 10
 disk-type = virtio
+disk-format = qcow2
+disk-device-path =
 
 cpu-count = 1
 cpu-max-count = 24

software/kvm/software.cfg

@@ -99,7 +99,7 @@ recipe = hexagonit.recipe.download
 ignore-existing = true
 url = ${:_profile_base_location_}/instance-kvm.cfg.jinja2
 mode = 644
-md5sum = 92e0723a2b474d9cc686ef7f0a91e36c
+md5sum = dbf43756c605144f0a3cd829b588d931 
 download-only = true
 on-update = true
 
@@ -186,7 +186,7 @@ ignore-existing = true
 url = ${:_profile_base_location_}/template/template-kvm-run.in
 mode = 644
 filename = template-kvm-run.in
-md5sum = 807e03a9ada561499adf447f79e9d2ec
+md5sum = 887585f23359d136093de42b1ad1d777
 download-only = true
 on-update = true
 

software/kvm/template/template-kvm-run.in

@@ -31,6 +31,7 @@ nbd_list = (('{{ parameter_dict.get("nbd-host") }}',
               {{ parameter_dict.get("nbd2-port") }}))
 default_cdrom_iso = '{{ parameter_dict.get("default-cdrom-iso") }}'
 disk_path = '{{ parameter_dict.get("disk-path") }}'
+
 virtual_hard_drive_url = '{{ parameter_dict.get("virtual-hard-drive-url") }}'.strip()
 virtual_hard_drive_md5sum = '{{ parameter_dict.get("virtual-hard-drive-md5sum") }}'.strip()
 virtual_hard_drive_gzipped = '{{ parameter_dict.get("virtual-hard-drive-gzipped") }}'.strip().lower()
@@ -74,6 +75,16 @@ disk_cache = disk_cache if disk_cache in ["none", "writeback", "unsafe",
               "directsync", "writethrough"] else "writeback"
 disk_aio = '{{ parameter_dict.get("disk-aio", "threads") }}'.strip()
 disk_aio = disk_aio if disk_aio in ["threads", "native"] else "threads"
+
+# If a device (ie.: /dev/sdb) is provided, use it instead 
+# the disk_path with disk_format
+disk_device_path = '{{ parameter_dict.get("disk-device-path", "") }}'
+if disk_device_path.startswith("/dev/"):
+  disk_path = disk_device_path 
+  disk_format = "raw" 
+  disk_aio = "native"
+  disk_cache = "none"
+
 smp_count = {{ parameter_dict.get("smp-count") }}
 smp_max_count = {{ parameter_dict.get("smp-max-count") }}
 machine_options = '{{ parameter_dict.get("machine-options", "") }}'.strip()
@@ -189,7 +200,7 @@ if not os.path.exists(disk_path) and virtual_hard_drive_url != '':
 
 # Create disk if doesn't exist
 # XXX: move to Buildout profile
-if not os.path.exists(disk_path):
+if not disk_device_path.startswith("/dev/") and not os.path.exists(disk_path):
   print('Creating virtual hard drive...')
   subprocess.check_call([qemu_img_path, 'create' ,'-f', disk_format,
       disk_path, '%sG' % disk_size])