Clarify direct migration

When --direct is used when migrating a domain running on a hypervisor
that does not support direct migration (such as QEMU), the caller would
get the following error message:

    this function is not supported by the connection driver:
    virDomainMigrateToURI2

which is a complete nonsense since qemu driver implements
virDomainMigrateToURI2. This patch would emit a more sensible error in
this case:

    Requested operation is not valid: direct migration is not supported
    by the connection driver

diff --git a/src/libvirt.c b/src/libvirt.c
index db6ba15e1b7f133bcd1dc91c39475762b89f823c..df78e8aca70413c699536f306996ace287041a4a 100644 (file)
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -5562,7 +5562,9 @@ virDomainMigrateToURI (virDomainPtr domain,
                 goto error;
         } else {
             /* Cannot do a migration with only the perform step */
-            virLibConnError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
+            virLibConnError(VIR_ERR_OPERATION_INVALID, "%s",
+                            _("direct migration is not supported by the"
+                              " connection driver"));
             goto error;
         }
     }
@@ -5696,7 +5698,9 @@ virDomainMigrateToURI2(virDomainPtr domain,
                 goto error;
         } else {
             /* Cannot do a migration with only the perform step */
-            virLibConnError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
+            virLibConnError(VIR_ERR_OPERATION_INVALID, "%s",
+                            _("direct migration is not supported by the"
+                              " connection driver"));
             goto error;
         }
     }

diff --git a/tools/virsh.pod b/tools/virsh.pod
index ae00622ad28c9992dd7bf196f679a736e0f84620..4bddf15fff0c427c2702fa1832e4298f2a9029a2 100644 (file)
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -990,6 +990,9 @@ is implicitly enabled when supported by the hypervisor, but can be explicitly
 used to reject the migration if the hypervisor lacks change protection
 support.  I<--verbose> displays the progress of migration.
 
+B<Note>: Individual hypervisors usually do not support all possible types of
+migration. For example, QEMU does not support direct migration.
+
 In some cases libvirt may refuse to migrate the domain because doing so may
 lead to potential problems such as data corruption, and thus the migration is
 considered unsafe. For QEMU domain, this may happen if the domain uses disks