Merge ~andreserl/maas:lp1642298 into maas:master

[Andres Rodriguez]

LP: #1642298 - Grub upgrades overwrites NVRAM, breaking MAAS boot order.

Grub2 package upgrades overwrite the NVRAM. This causes the MAAS written NVRAM to be overwritten, which causes machines to be unable to PXE boot in subsequent reboots.

[Blake Rouse (blake-rouse)]

Looks good.

review: Approve

[MAAS Lander (maas-lander)]

LANDING
-b lp1642298 lp:~andreserl/maas into -b master lp:~maas-committers/maas

STATUS: FAILED BUILD
LOG: http://maas-ci-jenkins.internal:8080/job/maas/job/branch-tester/322/consoleText

diff --git a/src/maasserver/preseed.py b/src/maasserver/preseed.py
index bee1ffe..3475dd0 100644
--- a/src/maasserver/preseed.py
+++ b/src/maasserver/preseed.py
@@ -524,6 +524,13 @@ def get_curtin_config(node):
     # must have this statement.
     if node.distro_series == "precise":
         config['power_state'] = {'mode': 'reboot'}
+    # Ensure we always set debconf_selections for grub to ensure it doesn't
+    # overwrite the config sent by MAAS. See LP: #1642298
+    grub2_debconf = {'grub2': 'grub2   grub2/update_nvram  boolean false'}
+    if 'debconf_selections' in config:
+        config['debconf_selections'].update(grub2_debconf)
+    else:
+        config['debconf_selections'] = grub2_debconf
     return yaml.safe_dump(config)
 
 
diff --git a/src/maasserver/tests/test_preseed.py b/src/maasserver/tests/test_preseed.py
index a6eb6ba..d78b267 100644
--- a/src/maasserver/tests/test_preseed.py
+++ b/src/maasserver/tests/test_preseed.py
@@ -1149,6 +1149,16 @@ class TestCurtinUtilities(
             yaml_conf['late_commands']['maas'][2])
         self.assertTrue('debconf_selections' in yaml_conf)
 
+    def test_get_curtin_config_has_grub2_debconf_selections(self):
+        node = factory.make_Node_with_Interface_on_Subnet(
+            primary_rack=self.rpc_rack_controller)
+        node.save()
+        self.configure_get_boot_images_for_node(node, 'xinstall')
+        config = get_curtin_config(node)
+        self.assertThat(
+            config,
+            Contains('grub2: grub2   grub2/update_nvram  boolean false'))
+
     def make_fastpath_node(self, main_arch=None):
         """Return a `Node`, with FPI enabled, and the given main architecture.