Force boot from volume

nova.patch

From: =?UTF-8?q?Mathieu=20Gagn=C3=A9?= <mgagne@iweb.com>
Date: Tue, 25 Feb 2014 13:38:00 -0500
Subject: Add FlavorDiskBackendMiddleware

Adds the ability to change default disk backend from flavor extra_specs by
setting 'disk:default_backend' to 'volume'.
---
 .../compute/plugins/v3/flavor_diskbackend.py       |  104 ++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 nova/api/openstack/compute/plugins/v3/flavor_diskbackend.py

diff --git a/nova/api/openstack/compute/plugins/v3/flavor_diskbackend.py b/nova/api/openstack/compute/plugins/v3/flavor_diskbackend.py
new file mode 100644
index 0000000..ed4fcef
--- /dev/null
+++ b/nova/api/openstack/compute/plugins/v3/flavor_diskbackend.py
@@ -0,0 +1,104 @@
+"""
+Flavor default disk backend Middleware plugin.
+
+Adds the ability to change default disk backend from flavor extra_specs by
+setting 'disk:default_backend' to 'volume'.
+
+This middleware plugin should be added to the openstack_compute_api_v2 pipeline
+defined in the paste config, /etc/nova/api-paste.ini
+
+The filter should be added to the pipeline just before the osapi_compute_app_v2:
+
+  [filter:flavor_diskbackend]
+  paste.filter_factory = nova.api.openstack.compute.plugins.v3.flavor_diskbackend:FlavorDiskBackendMiddleware.factory
+
+  [composite:openstack_compute_api_v2]
+  use = call:nova.api.auth:pipeline_factory
+  noauth = faultwrap sizelimit noauth ratelimit flavor_diskbackend osapi_compute_app_v2
+  keystone = faultwrap sizelimit authtoken keystonecontext ratelimit flavor_diskbackend osapi_compute_app_v2
+  keystone_nolimit = faultwrap sizelimit authtoken keystonecontext flavor_diskbackend osapi_compute_app_v2
+"""
+
+import json
+import posixpath
+
+from oslo_log import log as logging
+import webob.dec
+import webob.exc
+
+from nova.api.openstack import wsgi
+from nova import db
+from nova import exception
+from nova import wsgi as base_wsgi
+
+
+LOG = logging.getLogger(__name__)
+
+
+class FlavorDiskBackendMiddleware(base_wsgi.Middleware):
+
+    @webob.dec.wsgify(RequestClass=wsgi.Request)
+    def __call__(self, request):
+        method = request.method
+        path = posixpath.normpath(request.path)
+        path_tokens = path.split('/')[1:]
+        # path_tokens[0] == version
+        # path_tokens[1] == project_id
+        # path_tokens[2] == resource
+        if (len(path_tokens) < 3):
+            return self.application
+        resource = path_tokens[2]
+        LOG.debug("Resource=%s  Method=%s" % (resource, method))
+        if method == 'POST' and resource == 'servers':
+            self._create_server(request)
+        return self.application
+
+    def _create_server(self, request):
+        LOG.debug('Processing server create')
+        ctxt = request.environ.get("nova.context")
+        payload = json.loads(request.body)
+        server = payload.get('server')
+
+        if not server:
+            return
+        if 'block_device_mapping' in server:
+            return
+        if 'block_device_mapping_v2' in server:
+            return
+
+        flavor_id = server.get('flavorRef')
+        if not flavor_id:
+            return
+
+        try:
+            extra_specs = db.flavor_extra_specs_get(ctxt, flavor_id)
+        except exception.NotFound:
+            return
+
+        default_backend = extra_specs.get('disk:default_backend', 'local')
+        if default_backend != 'volume':
+            return
+
+        image_id = server.get('imageRef')
+        if not image_id:
+            return
+
+        # NOTE(mgagne) When using BFV, imageRef must be empty
+        server['imageRef'] = ''
+
+        flavor = db.flavor_get_by_flavor_id(ctxt, flavor_id)
+
+        # NOTE(mgagne) Use root_gb from flavor as volume size
+        server['block_device_mapping_v2'] = [{
+            'source_type': 'image',
+            'boot_index': '0',
+            'destination_type': 'volume',
+            'uuid': image_id,
+            'volume_size': flavor['root_gb'],
+            'delete_on_termination': True,
+        }]
+
+        payload['server'] = server
+        request.body = json.dumps(payload)
+        LOG.debug('Create payload rewritten for boot-from-volume')
+