Merge ~newell-jensen/maas:lp1702690 into maas:master

[Newell Jensen]

Set the machine's min_hwe_kernel to the setting's default_min_hwe_kernel when commissioning.

[Andres Rodriguez (andreserl)]

lgtm! But before you land, please add a new test (see inline)

review: Approve

[Mike Pontillo (mpontillo)]

Why do we have a min_hwe_kernel in the node model if we're just using the global config every time? Should it be removed, or is there another use case for it? Should we instead only set it to the global config during commissioning if the global configured minimum is greater than the current setting (if set)?

review: Needs Information

[Andres Rodriguez (andreserl)]

This is for commissioning only. Commissioning should always use whatever is the global setting. (this doesn't affect deployment).

For example, say we set the kernel in settings to ga-16.04. The machine boots fine, maas sets that min_hwe_kernel for the node, but the node fail because it cannot work on ga-16.04. So, we need hwe-16.04, and so we change it in the settings. As it stands today, when we try to commission again it will use 'ga-16.04' because that's the min, completely ignoring the fact that hwe-16.04 is set, hence always preventing the machine from booting because it will always try to boot ga-16.04.

That said, with the fix, it will always ensure we boot what's set on the global setting.

2fff8e0... by Newell Jensen on 2017-07-14

Add back unit test where node is in NEW state and the min_hwe_kernel is not set. Update new unit test to be in a READY state.

diff --git a/src/maasserver/models/node.py b/src/maasserver/models/node.py
index 74028a2..0b92fb1 100644
--- a/src/maasserver/models/node.py
+++ b/src/maasserver/models/node.py
@@ -1806,12 +1806,11 @@ class Node(CleanSave, TimestampedModel):
         old_status = self.status
         self.status = NODE_STATUS.COMMISSIONING
         self.owner = user
-        # Set min_hwe_kernel to min_hwe_kernel if it isn't set incase
-        # commissioning failed and the user set the min globally and is
-        # retrying.
-        if not self.min_hwe_kernel:
-            self.min_hwe_kernel = Config.objects.get_config(
-                'default_min_hwe_kernel')
+        # Set min_hwe_kernel to default_min_hwe_kernel.
+        # This makes sure that the min_hwe_kernel is up to date
+        # with what is stored in the settings.
+        self.min_hwe_kernel = Config.objects.get_config(
+            'default_min_hwe_kernel')
         self.save()
 
         try:
diff --git a/src/maasserver/models/tests/test_node.py b/src/maasserver/models/tests/test_node.py
index bbd7915..60d82db 100644
--- a/src/maasserver/models/tests/test_node.py
+++ b/src/maasserver/models/tests/test_node.py
@@ -2465,7 +2465,7 @@ class TestNode(MAASServerTestCase):
         self.assertThat(node_start, MockCalledOnceWith(
             admin, user_data, NODE_STATUS.NEW, allow_power_cycle=True))
 
-    def test_start_commissioning_sets_min_hwe_kernel(self):
+    def test_start_commissioning_sets_min_hwe_kernel_when_not_set(self):
         node = factory.make_Node(status=NODE_STATUS.NEW)
         node_start = self.patch(node, '_start')
         node_start.side_effect = (
@@ -2476,10 +2476,27 @@ class TestNode(MAASServerTestCase):
             node_module, 'generate_user_data_for_status')
         generate_user_data_for_status.return_value = user_data
         admin = factory.make_admin()
-        Config.objects.set_config('default_min_hwe_kernel', 'hwe-v')
+        Config.objects.set_config('default_min_hwe_kernel', 'hwe-16.04')
         node.start_commissioning(admin)
         post_commit_hooks.reset()  # Ignore these for now.
-        self.assertEqual('hwe-v', node.min_hwe_kernel)
+        self.assertEqual('hwe-16.04', node.min_hwe_kernel)
+
+    def test_start_commissioning_sets_min_hwe_kernel_when_previously_set(self):
+        node = factory.make_Node(
+            status=NODE_STATUS.READY, min_hwe_kernel='ga-16.04')
+        node_start = self.patch(node, '_start')
+        node_start.side_effect = (
+            lambda user, user_data, old_status, allow_power_cycle: (
+                post_commit()))
+        user_data = factory.make_string().encode('ascii')
+        generate_user_data_for_status = self.patch(
+            node_module, 'generate_user_data_for_status')
+        generate_user_data_for_status.return_value = user_data
+        admin = factory.make_admin()
+        Config.objects.set_config('default_min_hwe_kernel', 'hwe-16.04')
+        node.start_commissioning(admin)
+        post_commit_hooks.reset()  # Ignore these for now.
+        self.assertEqual('hwe-16.04', node.min_hwe_kernel)
 
     def test_start_commissioning_starts_node_if_already_on(self):
         node = factory.make_Node(