Add pxe template per node

Allow to pass a pxe_template field in driver_info. If that is
present, it will search for the template file specified there,
instead of checking the per-arch/agent templates.

Change-Id: I436a61ad6a3e688bc6f833f5645c99be6d7e26e7
Story: #2004525
Task: #28264

ironic/drivers/modules/deploy_utils.py

@@ -735,12 +735,15 @@ def get_pxe_config_template(node):
     """Return the PXE config template file name requested for deploy.
 
     This method returns PXE config template file to be used for deploy.
-    Architecture specific template file is searched first. BIOS/UEFI
-    template file is used if no valid architecture specific file found.
+    First specific pxe template is searched in the node. After that
+    architecture specific template file is searched. BIOS/UEFI template file
+    is used if no valid architecture specific file found.
 
     :param node: A single Node.
     :returns: The PXE config template file name.
     """
+    config_template = node.driver_info.get("pxe_template", None)
+    if config_template is None:
         cpu_arch = node.properties.get('cpu_arch')
         config_template = CONF.pxe.pxe_config_template_by_arch.get(cpu_arch)
         if config_template is None:

ironic/tests/unit/drivers/modules/test_deploy_utils.py

@@ -1113,6 +1113,14 @@ class GetPxeBootConfigTestCase(db_base.DbTestCase):
         result = utils.get_pxe_config_template(self.node)
         self.assertEqual('bios-template', result)
 
+    def test_get_pxe_config_template_per_node(self):
+        node = obj_utils.create_test_node(
+            self.context, driver='fake-hardware',
+            driver_info={"pxe_template": "fake-template"},
+        )
+        result = utils.get_pxe_config_template(node)
+        self.assertEqual('fake-template', result)
+
 
 @mock.patch('time.sleep', lambda sec: None)
 class OtherFunctionTestCase(db_base.DbTestCase):

releasenotes/notes/add-pxe-per-node-526fd79df17efda8.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    Add a new field pxe_template that can be set at driver-info level. This
+    will specify a path for a custom pxe boot template. If present, this
+    template will be read and will have priority in front of the per-arch and
+    general pxe templates.
+