Merge "Use base image for rescue instance."

2 files changed, 34 insertions, 8 deletions

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index fed8b32d3..9011196b2 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -1484,6 +1484,27 @@ class ComputeManager(manager.SchedulerDependentManager):
                     instance=instance)
         self.driver.inject_file(instance, path, file_contents)
 
+    def _get_rescue_image_ref(self, context, instance):
+        """Determine what image should be used to boot the rescue VM. """
+        system_meta = self.db.instance_system_metadata_get(
+                context, instance['uuid'])
+
+        rescue_image_ref = system_meta.get('image_base_image_ref')
+
+        # 1. First try to use base image associated with instance's current
+        #    image.
+        #
+        # The idea here is to provide the customer with a rescue environment
+        # which they are familiar with. So, if they built their instance off of
+        # a Debian image, their rescue VM wil also be Debian.
+        if rescue_image_ref:
+            return rescue_image_ref
+
+        # 2. As a last resort, use instance's current image
+        LOG.warn(_('Unable to find a different image to use for rescue VM,'
+                   ' using instance\'s current image'))
+        return instance['image_ref']
+
     @exception.wrap_exception(notifier=notifier, publisher_id=publisher_id())
     @reverts_task_state
     @wrap_instance_fault
@@ -1499,12 +1520,16 @@ class ComputeManager(manager.SchedulerDependentManager):
                       utils.generate_password(CONF.password_length))
 
         network_info = self._get_instance_nw_info(context, instance)
-        image_meta = _get_image_meta(context, instance['image_ref'])
+
+        # Boot the instance using the 'base' image instead of the user's
+        # current (possibly broken) image
+        rescue_image_ref = self._get_rescue_image_ref(context, instance)
+        rescue_image_meta = _get_image_meta(context, rescue_image_ref)
 
         with self._error_out_instance_on_exception(context, instance['uuid']):
             self.driver.rescue(context, instance,
-                               self._legacy_nw_info(network_info), image_meta,
-                               admin_password)
+                               self._legacy_nw_info(network_info),
+                               rescue_image_meta, admin_password)
 
         current_power_state = self._get_power_state(context, instance)
         self._instance_update(context,
diff --git a/nova/virt/xenapi/vmops.py b/nova/virt/xenapi/vmops.py
index cc0d48d22..df25b9992 100644
--- a/nova/virt/xenapi/vmops.py
+++ b/nova/virt/xenapi/vmops.py
@@ -238,10 +238,10 @@ class VMOps(object):
                                   False, False)
 
     def _create_disks(self, context, instance, name_label, disk_image_type,
-                      block_device_info=None):
+                      image_meta, block_device_info=None):
         vdis = vm_utils.get_vdis_for_instance(context, self._session,
                                           instance, name_label,
-                                          instance['image_ref'],
+                                          image_meta['id'],
                                           disk_image_type,
                                           block_device_info=block_device_info)
         # Just get the VDI ref once
@@ -269,9 +269,10 @@ class VMOps(object):
             return vm_utils.determine_disk_image_type(image_meta)
 
         @step
-        def create_disks_step(undo_mgr, disk_image_type):
+        def create_disks_step(undo_mgr, disk_image_type, image_meta):
             vdis = self._create_disks(context, instance, name_label,
-                                      disk_image_type, block_device_info)
+                                      disk_image_type, image_meta,
+                                      block_device_info)
 
             def undo_create_disks():
                 vdi_refs = [vdi['ref'] for vdi in vdis.values()
@@ -387,7 +388,7 @@ class VMOps(object):
             bdev_set_default_root(undo_mgr)
             disk_image_type = determine_disk_image_type_step(undo_mgr)
 
-            vdis = create_disks_step(undo_mgr, disk_image_type)
+            vdis = create_disks_step(undo_mgr, disk_image_type, image_meta)
             kernel_file, ramdisk_file = create_kernel_ramdisk_step(undo_mgr)
             vm_ref = create_vm_record_step(undo_mgr, vdis, disk_image_type,
                     kernel_file, ramdisk_file)