(2.13) kvm: Add migration capabilities as an hvparam

Latest QEMU versions support various migration capabilities.  Each
can be enabled/disabled with 'migrate_set_capability' monitor
command.

Version 1.7.0 defines x-rdma-pin-all, auto-converge, zero-blocks,
and xbzrle migration capabilities.

Since migration capabilities are more than one, and because hvparams
accept only strings/integers and not dicts we decide to provide the
capabilities that should be on via a ":" separated string.

In other words one can use the following to enable xbzrle and
auto-converge:

-H kvm:migration_caps=xbzrle:auto-converge

IMPORTANT: xbzrle may result to BSOD for instances running Windows
2008r8 on drbd.

Update man page of gnt-instance to include the new hvparam.

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>

diff --git a/lib/constants.py b/lib/constants.py
index d72afc8..f5c0659 100644 (file)
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -948,6 +948,7 @@ HV_MIGRATION_PORT = "migration_port"
 HV_MIGRATION_BANDWIDTH = "migration_bandwidth"
 HV_MIGRATION_DOWNTIME = "migration_downtime"
 HV_MIGRATION_MODE = "migration_mode"
+HV_KVM_MIGRATION_CAPS = "migration_caps"
 HV_USE_LOCALTIME = "use_localtime"
 HV_DISK_CACHE = "disk_cache"
 HV_SECURITY_MODEL = "security_model"
@@ -1021,6 +1022,7 @@ HVS_PARAMETER_TYPES = {
   HV_MIGRATION_BANDWIDTH: VTYPE_INT,
   HV_MIGRATION_DOWNTIME: VTYPE_INT,
   HV_MIGRATION_MODE: VTYPE_STRING,
+  HV_KVM_MIGRATION_CAPS: VTYPE_STRING,
   HV_USE_LOCALTIME: VTYPE_BOOL,
   HV_DISK_CACHE: VTYPE_STRING,
   HV_SECURITY_MODEL: VTYPE_STRING,
@@ -2124,6 +2126,7 @@ HVC_DEFAULTS = {
     HV_MIGRATION_BANDWIDTH: 32, # MiB/s
     HV_MIGRATION_DOWNTIME: 30,  # ms
     HV_MIGRATION_MODE: HT_MIGRATION_LIVE,
+    HV_KVM_MIGRATION_CAPS: "",
     HV_USE_LOCALTIME: False,
     HV_DISK_CACHE: HT_CACHE_DEFAULT,
     HV_SECURITY_MODEL: HT_SM_NONE,

diff --git a/lib/hypervisor/hv_kvm.py b/lib/hypervisor/hv_kvm.py
index a38943a..b1e93da 100644 (file)
--- a/lib/hypervisor/hv_kvm.py
+++ b/lib/hypervisor/hv_kvm.py
@@ -114,6 +114,8 @@ _RUNTIME_ENTRY = {
   constants.HOTPLUG_TARGET_DISK: lambda d, e: (d, e)
   }
 
+_MIGRATION_CAPS_DELIM = ":"
+
 
 def _GenerateDeviceKVMId(dev_type, dev, idx=None):
   """Helper function to generate a unique device name used by KVM
@@ -702,6 +704,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     constants.HV_MIGRATION_BANDWIDTH: hv_base.REQ_NONNEGATIVE_INT_CHECK,
     constants.HV_MIGRATION_DOWNTIME: hv_base.REQ_NONNEGATIVE_INT_CHECK,
     constants.HV_MIGRATION_MODE: hv_base.MIGRATION_MODE_CHECK,
+    constants.HV_KVM_MIGRATION_CAPS: hv_base.NO_CHECK,
     constants.HV_USE_LOCALTIME: hv_base.NO_CHECK,
     constants.HV_DISK_CACHE:
       hv_base.ParamInSet(True, constants.HT_VALID_CACHE_TYPES),
@@ -2520,6 +2523,17 @@ class KVMHypervisor(hv_base.BaseHypervisor):
                        instance.hvparams[constants.HV_MIGRATION_DOWNTIME])
     self._CallMonitorCommand(instance_name, migrate_command)
 
+    # These commands are supported in latest qemu versions.
+    # Since _CallMonitorCommand does not catch monitor errors
+    # this does not raise an exception in case command is not supported
+    # TODO: either parse output of command or see if the command supported
+    # via info help (see hotplug)
+    migration_caps = instance.hvparams[constants.HV_KVM_MIGRATION_CAPS]
+    if migration_caps:
+      for c in migration_caps.split(_MIGRATION_CAPS_DELIM):
+        migrate_command = ("migrate_set_capability %s on" % c)
+        self._CallMonitorCommand(instance_name, migrate_command)
+
     migrate_command = "migrate -d tcp:%s:%s" % (target, port)
     self._CallMonitorCommand(instance_name, migrate_command)
 

diff --git a/man/gnt-instance.rst b/man/gnt-instance.rst
index 7f4bdec..c97e14c 100644 (file)
--- a/man/gnt-instance.rst
+++ b/man/gnt-instance.rst
@@ -762,6 +762,16 @@ machine\_version
     machine version (due to e.g. outdated drivers). In case it's not set
     the default version supported by your version of kvm is used.
 
+migration\_caps
+    Valid for the KVM hypervisor.
+
+    Enable specific migration capabilities by providing a ":" separated
+    list of supported capabilites. QEMU version 1.7.0 defines
+    x-rdma-pin-all, auto-converge, zero-blocks, and xbzrle. Please note
+    that while a combination of xbzrle and auto-converge might speed up
+    the migration process significantly, the first may cause BSOD on
+    Windows8r2 instances running on drbd.
+
 kvm\_path
     Valid for the KVM hypervisor.