From 9e9520a4b07a841595572c9084870cae12a96b78 Mon Sep 17 00:00:00 2001
From: Surya Seetharaman <suryaseetharaman.9@gmail.com>
Date: Thu, 22 Mar 2018 19:26:05 +0100
Subject: [PATCH] Add disabled option to create_cell command

Specifying this new option will create pre-disabled cells.

Related to blueprint cell-disable

Change-Id: I87e06eeefd48f640f42fcc5ff5a48938adc2ac22
---
 doc/source/cli/nova-manage.rst                    |  6 ++++--
 nova/cmd/manage.py                                |  7 +++++--
 nova/tests/unit/test_nova_manage.py               | 15 +++++++++++++++
 ...-disabled-to-create_cell-feb1643ec4716eb2.yaml |  6 ++++++
 4 files changed, 30 insertions(+), 4 deletions(-)
 create mode 100644 releasenotes/notes/add-disabled-to-create_cell-feb1643ec4716eb2.yaml

diff --git a/doc/source/cli/nova-manage.rst b/doc/source/cli/nova-manage.rst
index ccca7f9b7ef7..423a04ced675 100644
--- a/doc/source/cli/nova-manage.rst
+++ b/doc/source/cli/nova-manage.rst
@@ -188,7 +188,7 @@ Nova Cells v2
     instance which has instance mapping, and 4 if it is an archived instance
     which still has an instance mapping.
 
-``nova-manage cell_v2 create_cell [--name <cell_name>] [--transport-url <transport_url>] [--database_connection <database_connection>] [--verbose]``
+``nova-manage cell_v2 create_cell [--name <cell_name>] [--transport-url <transport_url>] [--database_connection <database_connection>] [--verbose] [--disabled]``
     Create a cell mapping to the database connection and message queue
     transport url. If a database_connection is not specified, it will use the
     one defined by ``[database]/connection`` in the configuration file passed
@@ -197,7 +197,9 @@ Nova Cells v2
     verbose option will print out the resulting cell mapping uuid.  Returns 0
     if the cell mapping was successfully created, 1 if the transport url or
     database connection was missing, and 2 if a cell is already using that
-    transport url and database connection combination.
+    transport url and database connection combination. All the cells created are
+    by default enabled. However passing the disabled option can create a pre-disabled
+    cell, meaning no scheduling will happen to this cell.
 
 ``nova-manage cell_v2 discover_hosts [--cell_uuid <cell_uuid>] [--verbose] [--strict]``
     Searches cells, or a single cell, and maps found hosts. This command will
diff --git a/nova/cmd/manage.py b/nova/cmd/manage.py
index 9a5975541d17..0dd7a46a46da 100644
--- a/nova/cmd/manage.py
+++ b/nova/cmd/manage.py
@@ -1365,8 +1365,10 @@ class CellV2Commands(object):
           help=_('The transport url for the cell message queue'))
     @args('--verbose', action='store_true',
           help=_('Output the uuid of the created cell'))
+    @args('--disabled', action='store_true',
+          help=_('To create a pre-disabled cell.'))
     def create_cell(self, name=None, database_connection=None,
-                    transport_url=None, verbose=False):
+                    transport_url=None, verbose=False, disabled=False):
         ctxt = context.get_context()
         transport_url = transport_url or CONF.transport_url
         if not transport_url:
@@ -1387,7 +1389,8 @@ class CellV2Commands(object):
             ctxt,
             uuid=cell_mapping_uuid, name=name,
             transport_url=transport_url,
-            database_connection=database_connection)
+            database_connection=database_connection,
+            disabled=disabled)
         cell_mapping.create()
         if verbose:
             print(cell_mapping_uuid)
diff --git a/nova/tests/unit/test_nova_manage.py b/nova/tests/unit/test_nova_manage.py
index e4e14c7cf4b1..e84c05e4b32e 100644
--- a/nova/tests/unit/test_nova_manage.py
+++ b/nova/tests/unit/test_nova_manage.py
@@ -1679,6 +1679,7 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         self.assertEqual(kwargs['database_connection'],
                          cell2.database_connection)
         self.assertEqual(kwargs['transport_url'], cell2.transport_url)
+        self.assertIs(cell2.disabled, False)
 
     def test_create_cell_use_config_values(self):
         settings = dict(
@@ -1720,6 +1721,20 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         self.assertEqual(1, status)
         self.assertIn('--database_connection', self.output.getvalue())
 
+    def test_create_cell_pre_disabled(self):
+        ctxt = context.get_context()
+        kwargs = dict(
+            name='fake-name1',
+            transport_url='fake-transport-url1',
+            database_connection='fake-db-connection1')
+        status1 = self.commands.create_cell(verbose=True, disabled=True,
+                                            **kwargs)
+        self.assertEqual(0, status1)
+        cell_uuid1 = self.output.getvalue().strip()
+        cell1 = objects.CellMapping.get_by_uuid(ctxt, cell_uuid1)
+        self.assertEqual(kwargs['name'], cell1.name)
+        self.assertIs(cell1.disabled, True)
+
     def test_list_cells_no_cells_verbose_false(self):
         ctxt = context.RequestContext()
         cell_mapping0 = objects.CellMapping(
diff --git a/releasenotes/notes/add-disabled-to-create_cell-feb1643ec4716eb2.yaml b/releasenotes/notes/add-disabled-to-create_cell-feb1643ec4716eb2.yaml
new file mode 100644
index 000000000000..2a59ba054fe0
--- /dev/null
+++ b/releasenotes/notes/add-disabled-to-create_cell-feb1643ec4716eb2.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    A new option ``disabled`` has been added to nova-manage cell_v2 create_cell
+    command by which users can create pre-disabled cells. Hence unless such cells
+    are enabled, no VMs will be spawned on the hosts in these cells.