Merge ~ack/maas:1940977-3.0 into maas:3.0

[Alberto Donato]

LP:1940977 check for all required LXD extensions

This also adds check for the custom_block_volumes one, which is needed to
compose VMs with multiple disks.

[Adam Collard (adam-collard)]

review: Approve

[MAAS Lander (maas-lander)]

LANDING
-b 1940977-3.0 lp:~ack/maas/+git/maas into -b 3.0 lp:~maas-committers/maas

STATUS: FAILED BUILD
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/10771/consoleText

diff --git a/src/provisioningserver/drivers/pod/lxd.py b/src/provisioningserver/drivers/pod/lxd.py
index 4095e85..f754d42 100644
--- a/src/provisioningserver/drivers/pod/lxd.py
+++ b/src/provisioningserver/drivers/pod/lxd.py
@@ -76,6 +76,12 @@ LXD_BYTE_SUFFIXES = {
     "EiB": 1024 ** 6,
 }
 
+LXD_REQUIRED_EXTENSIONS = frozenset(
+    ("projects", "virtual-machines", "custom_block_volumes")
+)
+
+LXD_MIN_VERSION = "4.16"
+
 
 def convert_lxd_byte_suffixes(value, divisor=None):
     """Takes the value and converts to a proper integer
@@ -237,10 +243,7 @@ class LXDPodDriver(PodDriver):
     def discover_projects(self, pod_id: int, context: dict):
         """Discover the list of projects in a pod."""
         client = self._get_client(pod_id, context)
-        if not client.has_api_extension("projects"):
-            raise LXDPodError(
-                "Please upgrade your LXD host to 3.6+ for projects support."
-            )
+        self._check_required_extensions(client)
         return [
             {"name": project.name, "description": project.description}
             for project in client.projects.all()
@@ -251,11 +254,7 @@ class LXDPodDriver(PodDriver):
         """Discover all Pod host resources."""
         # Connect to the Pod and make sure it is valid.
         client = self._get_client(pod_id, context)
-        if not client.has_api_extension("virtual-machines"):
-            raise LXDPodError(
-                "Please upgrade your LXD host to 3.19+ for virtual machine support."
-            )
-
+        self._check_required_extensions(client)
         self._ensure_project(client)
 
         # get MACs for host interfaces. "unknown" interfaces are considered too
@@ -402,6 +401,16 @@ class LXDPodDriver(PodDriver):
         # Hints are updated on the region for LXDPodDriver.
         return DiscoveredPodHints()
 
+    def _check_required_extensions(self, client):
+        """Raise an error if the LXD server doesn't support all required features."""
+        all_extensions = set(client.host_info["api_extensions"])
+        missing_extensions = sorted(LXD_REQUIRED_EXTENSIONS - all_extensions)
+        if missing_extensions:
+            raise LXDPodError(
+                f"Please upgrade your LXD host to {LXD_MIN_VERSION} or higher "
+                f"to support the following extensions: {','.join(missing_extensions)}"
+            )
+
     def _get_machine_disks(
         self, requested_disks, storage_pools, default_storage_pool
     ):
diff --git a/src/provisioningserver/drivers/pod/tests/test_lxd.py b/src/provisioningserver/drivers/pod/tests/test_lxd.py
index 0b41f13..afb260a 100644
--- a/src/provisioningserver/drivers/pod/tests/test_lxd.py
+++ b/src/provisioningserver/drivers/pod/tests/test_lxd.py
@@ -149,7 +149,9 @@ class TestLXDPodDriver(MAASTestCase):
         context = self.make_parameters_context()
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.has_api_extension.return_value = True
+        client.host_info = {
+            "api_extensions": sorted(lxd_module.LXD_REQUIRED_EXTENSIONS),
+        }
         client.trusted = False
         driver = lxd_module.LXDPodDriver()
         endpoint = driver.get_url(context)
@@ -173,7 +175,9 @@ class TestLXDPodDriver(MAASTestCase):
         context.pop("project")
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.has_api_extension.return_value = True
+        client.host_info = {
+            "api_extensions": sorted(lxd_module.LXD_REQUIRED_EXTENSIONS),
+        }
         client.trusted = False
         driver = lxd_module.LXDPodDriver()
         endpoint = driver.get_url(context)
@@ -196,7 +200,9 @@ class TestLXDPodDriver(MAASTestCase):
         context = self.make_parameters_context()
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.has_api_extension.return_value = True
+        client.host_info = {
+            "api_extensions": sorted(lxd_module.LXD_REQUIRED_EXTENSIONS),
+        }
         client.trusted = False
         driver = lxd_module.LXDPodDriver()
         endpoint = driver.get_url(context)
@@ -314,18 +320,22 @@ class TestLXDPodDriver(MAASTestCase):
             yield driver.power_query(pod_id, context)
 
     @inlineCallbacks
-    def test_discover_requires_client_to_have_vm_support(self):
+    def test_discover_checks_required_extensions(self):
         context = self.make_parameters_context()
         driver = lxd_module.LXDPodDriver()
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.has_api_extension.return_value = False
-        error_msg = "Please upgrade your LXD host to *."
+        client.host_info = {
+            "api_extensions": sorted(
+                lxd_module.LXD_REQUIRED_EXTENSIONS - {"projects"}
+            ),
+        }
+        error_msg = (
+            "Please upgrade your LXD host to 4.16 or higher "
+            "to support the following extensions: projects"
+        )
         with ExpectedException(lxd_module.LXDPodError, error_msg):
             yield driver.discover(None, context)
-        self.assertThat(
-            client.has_api_extension, MockCalledOnceWith("virtual-machines")
-        )
 
     @inlineCallbacks
     def test_discover(self):
@@ -333,15 +343,15 @@ class TestLXDPodDriver(MAASTestCase):
         driver = lxd_module.LXDPodDriver()
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.has_api_extension.return_value = True
         name = factory.make_name("hostname")
         client.host_info = {
+            "api_extensions": sorted(lxd_module.LXD_REQUIRED_EXTENSIONS),
             "environment": {
                 "architectures": ["x86_64", "i686"],
                 "kernel_architecture": "x86_64",
                 "server_name": name,
                 "server_version": "1.2.3",
-            }
+            },
         }
         mac_address = factory.make_mac_address()
         lxd_net1 = Mock(type="physical")
@@ -381,15 +391,15 @@ class TestLXDPodDriver(MAASTestCase):
         driver = lxd_module.LXDPodDriver()
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.has_api_extension.return_value = True
         name = factory.make_name("hostname")
         client.host_info = {
+            "api_extensions": sorted(lxd_module.LXD_REQUIRED_EXTENSIONS),
             "environment": {
                 "architectures": ["x86_64", "i686"],
                 "kernel_architecture": "x86_64",
                 "server_name": name,
                 "server_version": "1.2.3",
-            }
+            },
         }
         mac_address = factory.make_mac_address()
         lxd_network = Mock(type="unknown")
@@ -405,14 +415,14 @@ class TestLXDPodDriver(MAASTestCase):
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
         client.project = project_name
-        client.has_api_extension.return_value = True
         client.host_info = {
+            "api_extensions": sorted(lxd_module.LXD_REQUIRED_EXTENSIONS),
             "environment": {
                 "architectures": ["x86_64", "i686"],
                 "kernel_architecture": "x86_64",
                 "server_name": factory.make_name("hostname"),
                 "server_version": "1.2.3",
-            }
+            },
         }
         client.projects.exists.return_value = True
         driver = lxd_module.LXDPodDriver()
@@ -426,16 +436,16 @@ class TestLXDPodDriver(MAASTestCase):
         project_name = context["project"]
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.project = project_name
-        client.has_api_extension.return_value = True
         client.host_info = {
+            "api_extensions": sorted(lxd_module.LXD_REQUIRED_EXTENSIONS),
             "environment": {
                 "architectures": ["x86_64", "i686"],
                 "kernel_architecture": "x86_64",
                 "server_name": factory.make_name("hostname"),
                 "server_version": "1.2.3",
-            }
+            },
         }
+        client.project = project_name
         client.projects.exists.return_value = False
         driver = lxd_module.LXDPodDriver()
         yield driver.discover(None, context)
@@ -451,18 +461,22 @@ class TestLXDPodDriver(MAASTestCase):
         )
 
     @inlineCallbacks
-    def test_discover_projects_requires_projects_support(self):
+    def test_discover_projects_checks_required_extensions(self):
         context = self.make_parameters_context()
         driver = lxd_module.LXDPodDriver()
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.has_api_extension.return_value = False
-        error_msg = "Please upgrade your LXD host to *."
+        client.host_info = {
+            "api_extensions": sorted(
+                lxd_module.LXD_REQUIRED_EXTENSIONS - {"virtual-machines"}
+            ),
+        }
+        error_msg = (
+            "Please upgrade your LXD host to 4.16 or higher "
+            "to support the following extensions: virtual-machines"
+        )
         with ExpectedException(lxd_module.LXDPodError, error_msg):
             yield driver.discover_projects(None, context)
-        self.assertThat(
-            client.has_api_extension, MockCalledOnceWith("projects")
-        )
 
     @inlineCallbacks
     def test_discover_projects(self):
@@ -470,15 +484,15 @@ class TestLXDPodDriver(MAASTestCase):
         driver = lxd_module.LXDPodDriver()
         Client = self.patch(lxd_module, "Client")
         client = Client.return_value
-        client.has_api_extension.return_value = True
         name = factory.make_name("hostname")
         client.host_info = {
+            "api_extensions": sorted(lxd_module.LXD_REQUIRED_EXTENSIONS),
             "environment": {
                 "architectures": ["x86_64", "i686"],
                 "kernel_architecture": "x86_64",
                 "server_name": name,
                 "server_version": "1.2.3",
-            }
+            },
         }
         proj1 = Mock()
         proj1.name = "proj1"
@@ -923,9 +937,6 @@ class TestLXDPodDriver(MAASTestCase):
         client.resources = {
             factory.make_name("rkey"): factory.make_name("rvalue")
         }
-        client.host_info = {
-            factory.make_name("hkey"): factory.make_name("hvalue")
-        }
 
         def mock_iface(name, mac):
             iface = Mock()