Adding ansible python interpreter as driver_info

This patch grants the possibility to change the ansible python
interpreter used on remote managed machines as per-node
driver_info option.
Follw-up of https://review.openstack.org/641376

Change-Id: Ic1a994970a5aef5bbbbaaa747818e7ac402912ad
Story: 2005159
Task: 29915

doc/source/admin/drivers/ansible.rst

@@ -231,6 +231,13 @@ ansible_clean_steps_config
     Default is taken from ``[ansible]/default_clean_steps_config`` option of the
     ironic configuration file (defaults to ``clean_steps.yaml``).
 
+ansible_python_interpreter
+    Absolute path to the python interpreter on the managed machine.
+    Default is taken from ``[ansible]/default_python_interpreter`` option of
+    the ironic configuration file.
+    Ansible uses ``/usr/bin/python`` by default.
+
+
 
 Customizing the deployment logic
 ================================

ironic/conf/ansible.py

@@ -136,8 +136,10 @@ opts = [
                       "'driver_info' field.")),
     cfg.StrOpt('default_python_interpreter',
                help=_("Absolute path to the python interpreter on the "
-                      "managed machines. By default, ansible uses "
-                      "/usr/bin/python")),
+                      "managed machines. It may be overridden by per-node "
+                      "'ansible_python_interpreter' option in node's "
+                      "'driver_info' field. "
+                      "By default, ansible uses /usr/bin/python")),
 ]
 
 

ironic/drivers/modules/ansible/deploy.py

@@ -73,6 +73,8 @@ OPTIONAL_PROPERTIES = {
     'ansible_clean_steps_config': _('Name of the file inside the '
                                     '"ansible_playbooks_path" folder with '
                                     'cleaning steps configuration. Optional.'),
+    'ansible_python_interpreter': _('Absolute path to the python interpreter '
+                                    'on the managed machines. Optional.'),
 }
 
 COMMON_PROPERTIES = OPTIONAL_PROPERTIES
@@ -101,6 +103,11 @@ def _parse_ansible_driver_info(node, action='deploy'):
     return os.path.basename(playbook), user, key
 
 
+def _get_python_interpreter(node):
+    return node.driver_info.get('ansible_python_interpreter',
+                                CONF.ansible.default_python_interpreter)
+
+
 def _get_configdrive_path(basename):
     return os.path.join(CONF.tempdir, basename + '.cndrive')
 
@@ -126,9 +133,9 @@ def _run_playbook(node, name, extra_vars, key, tags=None, notags=None):
     playbook = os.path.join(root, name)
     inventory = os.path.join(root, 'inventory')
     ironic_vars = {'ironic': extra_vars}
-    if CONF.ansible.default_python_interpreter:
-        ironic_vars['ansible_python_interpreter'] = (
-            CONF.ansible.default_python_interpreter)
+    python_interpreter = _get_python_interpreter(node)
+    if python_interpreter:
+        ironic_vars['ansible_python_interpreter'] = python_interpreter
     args = [CONF.ansible.ansible_playbook_script, playbook,
             '-i', inventory,
             '-e', json.dumps(ironic_vars),

ironic/tests/unit/drivers/modules/ansible/test_deploy.py

@@ -191,6 +191,35 @@ class TestAnsibleMethods(AnsibleDeployTestCaseBase):
                           "ironic": {"foo": "bar"}},
                          json.loads(all_vars))
 
+    @mock.patch.object(com_utils, 'execute', return_value=('out', 'err'),
+                       autospec=True)
+    def test__run_playbook_ansible_interpreter_override(self, execute_mock):
+        self.config(group='ansible', playbooks_path='/path/to/playbooks')
+        self.config(group='ansible', config_file_path='/path/to/config')
+        self.config(group='ansible', verbosity=3)
+        self.config(group='ansible',
+                    default_python_interpreter='/usr/bin/python3')
+        self.config(group='ansible', ansible_extra_args='--timeout=100')
+        self.node.driver_info['ansible_python_interpreter'] = (
+            '/usr/bin/python4')
+        extra_vars = {'foo': 'bar'}
+
+        ansible_deploy._run_playbook(self.node, 'deploy',
+                                     extra_vars, '/path/to/key',
+                                     tags=['spam'], notags=['ham'])
+
+        execute_mock.assert_called_once_with(
+            'env', 'ANSIBLE_CONFIG=/path/to/config',
+            'ansible-playbook', '/path/to/playbooks/deploy', '-i',
+            '/path/to/playbooks/inventory', '-e',
+            mock.ANY, '--tags=spam', '--skip-tags=ham',
+            '--private-key=/path/to/key', '-vvv', '--timeout=100')
+
+        all_vars = execute_mock.call_args[0][7]
+        self.assertEqual({"ansible_python_interpreter": "/usr/bin/python4",
+                          "ironic": {"foo": "bar"}},
+                         json.loads(all_vars))
+
     @mock.patch.object(com_utils, 'execute',
                        side_effect=processutils.ProcessExecutionError(
                            description='VIKINGS!'),
@@ -286,6 +315,16 @@ class TestAnsibleMethods(AnsibleDeployTestCaseBase):
             self.assertEqual(2, ansible_deploy._calculate_memory_req(task))
             image_mock.assert_called_once_with(task.context, 'fake-image')
 
+    def test__get_python_interpreter(self):
+        self.config(group='ansible',
+                    default_python_interpreter='/usr/bin/python3')
+        self.node.driver_info['ansible_python_interpreter'] = (
+            '/usr/bin/python4')
+
+        python_interpreter = ansible_deploy._get_python_interpreter(self.node)
+
+        self.assertEqual('/usr/bin/python4', python_interpreter)
+
     def test__get_configdrive_path(self):
         self.config(tempdir='/path/to/tmpdir')
         self.assertEqual('/path/to/tmpdir/spam.cndrive',

releasenotes/notes/add-ansible-python-interpreter-2035e0f23d407aaf.yaml

@@ -11,3 +11,5 @@ features:
     ``/usr/bin/python3``.
     The same interpreter will be used in all operations that use the
     ansible deploy interface.
+    It is also possible to override the value set in the configuration for a
+    node by passing ``ansible_python_interpreter`` in its ``driver_info``.