Switch reboot default

In light of recent issues reported with soft reboot we are chaning the
reboot method to a full reboot. This is intended to reduce the number of
requests we receive to investigate boot issues.

Author: rjschwei

doc/adoc/user_guide.adoc

@@ -171,20 +171,24 @@ tux > sudo zypper in SLES15-Migration
 ----
 +
 The `run_migration` uses `kexec` to boot into the kernel delivered with the
-upgrade image delivered by the SLES15-Migration package. Once this system
-is live after the `kexec` the distribution migration process is automatically
-started. However, `kexec` is not supported and does not function in certain
-conditions. For example, the `run_migration` utility does not work in Xen
-based environments or when kernel keys change.
+upgrade image delivered by the SLES{$VERSION}-Migration package.
 +
-If kexec causes a kernel panic this can cause the system to hang and the
-distribution migration to fail. In that case refer to this TID:
-https://www.suse.com/support/kb/doc/?id=000019733
-And set the "soft_reboot" customization option:
+On the s390x architecture this is the only package available and the
+the `run_migration` method is the only option to start the migration process.
+The migration process starts automatically once the `run_migration` command
+is issued.
++
+On all other architectures the `kexec`, i.e. use of `run_migration` is not
+supported. This path does not work in certain conditions, for example
+on Xen based environments or when kernel keys change.
++
+By default this method is disabled. Enabling soft reboot behavior via kexec
+requires an explicit configuration change on all architectures except s390x
+by setting the "soft_reboot" customization option:
 +
 [listing]
 ----
-echo "soft_reboot: false" >> /etc/sle-migration-service.yml
+echo "soft_reboot: true" >> /etc/sle-migration-service.yml
 ----
 
 Option 2 - Trigger via reboot::
@@ -303,9 +307,10 @@ debug: true|false
 ----
 
 Configure Reboot Method::
-By default, the migration system uses `kexec` to boot back into the host
-system once migration is complete.  If this is in any way problematic,
-a regular `reboot` can be requested by setting `soft_reboot: false`.
+By default, the migration system uses a full reboot to boot back into the
+host system once migration is complete. It is possible to configure the
+migration system to use `kexec`, i.e. use a soft reboot by setting
+`soft_reboot: true` in the configuration. A soft reboot may trigger issues.
 +
 [listing]
 ----

suse_migration_services/migration_config.py

@@ -180,7 +180,7 @@ def is_zypper_migration_plugin_requested(self):
         return self.config_data.get('use_zypper_migration', True)
 
     def is_soft_reboot_requested(self):
-        return self.config_data.get('soft_reboot', True)
+        return self.config_data.get('soft_reboot', False)
 
     def is_host_independent_initd_requested(self):
         return self.config_data.get('build_host_independent_initrd', False)

test/data/migration-config.yml

@@ -1,3 +1,4 @@
+soft_reboot: true
 preserve:
   rules:
   - /etc/udev/rules.d/*.rules

test/unit/units/reboot_test.py

@@ -37,6 +37,7 @@ def test_main_skip_reboot_due_to_debug_file_set(
     @patch.object(Defaults, 'get_migration_config_file')
     @patch.object(Defaults, 'get_system_migration_custom_config_file')
     @patch('suse_migration_services.units.reboot.Fstab')
+    @patch('suse_migration_services.migration_config.is_soft_reboot_requested')
     def test_main_kexec_reboot(
         self,
         mock_Fstab,
@@ -45,12 +46,14 @@ def test_main_kexec_reboot(
         mock_logger_setup,
         mock_Command_run,
         mock_os_path_exists,
+        mock_soft_reboot_state,
     ):
         def skip_device(device):
             if '/dev/mynode' in device:
                 return False
             return True
 
+        mock_soft_reboot_state.return_value = True
         mock_os_path_exists.side_effect = skip_device
         fstab = Fstab()
         fstab_mock = Mock()