Use a generic Xen hypervisor interface.

Abstract the parts of the Xen hypervisor interface shared by both PVM and
HVM into a generic interface, subclass the special case PVM from that.

Prepatch for adding HVM support.


Reviewed-by: iustinp

lib/constants.py

@@ -149,7 +149,7 @@ INSTANCE_REBOOT_HARD = "hard"
 INSTANCE_REBOOT_FULL = "full"
 
 # Hypervisor constants
-HT_XEN30 = "xen-3.0"
+HT_XEN_PVM30 = "xen-3.0"
 HT_FAKE = "fake"
 
-HYPER_TYPES = frozenset([HT_XEN30, HT_FAKE])
+HYPER_TYPES = frozenset([HT_XEN_PVM30, HT_FAKE])

lib/hypervisor.py

@@ -42,8 +42,8 @@ def GetHypervisor():
 
   """
   ht_kind = ssconf.SimpleStore().GetHypervisorType()
-  if ht_kind == constants.HT_XEN30:
-    cls = XenHypervisor
+  if ht_kind == constants.HT_XEN_PVM30:
+    cls = XenPvmHypervisor
   elif ht_kind == constants.HT_FAKE:
     cls = FakeHypervisor
   else:
@@ -124,48 +124,19 @@ class BaseHypervisor(object):
 
 
 class XenHypervisor(BaseHypervisor):
-  """Xen hypervisor interface"""
+  """Xen generic hypervisor interface
+
+  This is the Xen base class used for both Xen PVM and HVM. It contains
+  all the functionality that is identical for both.
+
+  """
 
   @staticmethod
   def _WriteConfigFile(instance, block_devices, extra_args):
-    """Create a Xen 3.0 config file.
+    """A Xen instance config file.
 
     """
-    config = StringIO()
-    config.write("# this is autogenerated by Ganeti, please do not edit\n#\n")
-    config.write("kernel = '%s'\n" % constants.XEN_KERNEL)
-    if os.path.exists(constants.XEN_INITRD):
-      config.write("ramdisk = '%s'\n" % constants.XEN_INITRD)
-    config.write("memory = %d\n" % instance.memory)
-    config.write("vcpus = %d\n" % instance.vcpus)
-    config.write("name = '%s'\n" % instance.name)
-
-    vif_data = []
-    for nic in instance.nics:
-      nic_str = "mac=%s, bridge=%s" % (nic.mac, nic.bridge)
-      ip = getattr(nic, "ip", None)
-      if ip is not None:
-        nic_str += ", ip=%s" % ip
-      vif_data.append("'%s'" % nic_str)
-
-    config.write("vif = [%s]\n" % ",".join(vif_data))
-
-    disk_data = ["'phy:%s,%s,w'" % (rldev.dev_path, cfdev.iv_name)
-                 for cfdev, rldev in block_devices]
-    config.write("disk = [%s]\n" % ",".join(disk_data))
-
-    config.write("root = '/dev/sda ro'\n")
-    config.write("on_poweroff = 'destroy'\n")
-    config.write("on_reboot = 'restart'\n")
-    config.write("on_crash = 'restart'\n")
-    if extra_args:
-      config.write("extra = '%s'\n" % extra_args)
-    # just in case it exists
-    utils.RemoveFile("/etc/xen/auto/%s" % instance.name)
-    f = open("/etc/xen/%s" % instance.name, "w")
-    f.write(config.getvalue())
-    f.close()
-    return True
+    raise NotImplementedError
 
   @staticmethod
   def _RemoveConfigFile(instance):
@@ -324,7 +295,7 @@ class XenHypervisor(BaseHypervisor):
     """Return a command for connecting to the console of an instance.
 
     """
-    return "xm console %s" % instance.name
+    raise NotImplementedError
 
 
   def Verify(self):
@@ -337,6 +308,58 @@ class XenHypervisor(BaseHypervisor):
       return "xend daemon is not running"
 
 
+class XenPvmHypervisor(XenHypervisor):
+  """Xen PVM hypervisor interface"""
+
+  @staticmethod
+  def _WriteConfigFile(instance, block_devices, extra_args):
+    """Create a Xen instance config file.
+
+    """
+    config = StringIO()
+    config.write("# this is autogenerated by Ganeti, please do not edit\n#\n")
+    config.write("kernel = '%s'\n" % constants.XEN_KERNEL)
+    if os.path.exists(constants.XEN_INITRD):
+      config.write("ramdisk = '%s'\n" % constants.XEN_INITRD)
+    config.write("memory = %d\n" % instance.memory)
+    config.write("vcpus = %d\n" % instance.vcpus)
+    config.write("name = '%s'\n" % instance.name)
+
+    vif_data = []
+    for nic in instance.nics:
+      nic_str = "mac=%s, bridge=%s" % (nic.mac, nic.bridge)
+      ip = getattr(nic, "ip", None)
+      if ip is not None:
+        nic_str += ", ip=%s" % ip
+      vif_data.append("'%s'" % nic_str)
+
+    config.write("vif = [%s]\n" % ",".join(vif_data))
+
+    disk_data = ["'phy:%s,%s,w'" % (rldev.dev_path, cfdev.iv_name)
+                 for cfdev, rldev in block_devices]
+    config.write("disk = [%s]\n" % ",".join(disk_data))
+
+    config.write("root = '/dev/sda ro'\n")
+    config.write("on_poweroff = 'destroy'\n")
+    config.write("on_reboot = 'restart'\n")
+    config.write("on_crash = 'restart'\n")
+    if extra_args:
+      config.write("extra = '%s'\n" % extra_args)
+    # just in case it exists
+    utils.RemoveFile("/etc/xen/auto/%s" % instance.name)
+    f = open("/etc/xen/%s" % instance.name, "w")
+    f.write(config.getvalue())
+    f.close()
+    return True
+
+  @staticmethod
+  def GetShellCommandForConsole(instance):
+    """Return a command for connecting to the console of an instance.
+
+    """
+    return "xm console %s" % instance.name
+
+
 class FakeHypervisor(BaseHypervisor):
   """Fake hypervisor interface.