[virt-tools-list] [RFC PATCH 1/4] virtManager: object: domain: Set time on resume

[Michael Weiser]

Use a potentially available agent inside the domain to update guest time
after resume. Based on the same function in Nova[1].

[1] https://github.com/openstack/nova/commit/414df1e56ea9df700756a1732125e06c5d97d792

Signed-off-by: Michael Weiser <michael.weiser at gmx.de>

https://bugzilla.redhat.com/show_bug.cgi?id=1222069
---
 virtManager/object/domain.py | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/virtManager/object/domain.py b/virtManager/object/domain.py
index 272c96b4..d720dca5 100644
--- a/virtManager/object/domain.py
+++ b/virtManager/object/domain.py
@@ -1137,6 +1137,34 @@ class vmmDomain(vmmLibvirtObject):
     def refresh_snapshots(self):
         self._snapshot_list = None
 
+    def _set_time(self):
+        """
+        Try to set VM time to the current value. This is typically useful when
+        clock wasn't running on the VM for some time (e.g. during suspension or
+        migration), especially if the time delay exceeds NTP tolerance.
+        It is not guaranteed that the time is actually set (it depends on guest
+        environment, especially QEMU agent presence) or that the set time is
+        very precise (NTP in the guest should take care of it if needed).
+
+        Heavily based on
+        https://github.com/openstack/nova/commit/414df1e56ea9df700756a1732125e06c5d97d792.
+        """
+        # retry an arbitrary number of times to give the agent some time to
+        # come back online after e.g. resuming the domain
+        attempt = 1
+        while attempt < 5:
+            t = time.time()
+            seconds = int(t)
+            nseconds = int((t - seconds) * 10 ** 9)
+            try:
+                self._backend.setTime(time={'seconds': seconds,
+                                            'nseconds': nseconds})
+                log.debug('Successfully set guest time')
+            except Exception as e:
+                log.debug('Failed to set time: %s', e)
+
+            attempt += 1
+
 
     ########################
     # XML Parsing routines #
@@ -1274,7 +1302,10 @@ class vmmDomain(vmmLibvirtObject):
 
     @vmmLibvirtObject.lifecycle_action
     def startup(self):
+        sync_time = self.has_managed_save()
         self._backend.create()
+        if sync_time:
+            self._set_time()
 
     @vmmLibvirtObject.lifecycle_action
     def suspend(self):
-- 
2.24.0