Merge ~ack/maas:1941050-3.0 into maas:3.0

[Alberto Donato]

LP:1941050 always install lxd from latest/stable when deploying a LXD VM host

[Alberto Donato (ack)]

review: Approve

diff --git a/src/metadataserver/tests/test_vendor_data.py b/src/metadataserver/tests/test_vendor_data.py
index e8fddfd..becbf22 100644
--- a/src/metadataserver/tests/test_vendor_data.py
+++ b/src/metadataserver/tests/test_vendor_data.py
@@ -396,7 +396,8 @@ class TestGenerateKVMPodConfiguration(MAASServerTestCase):
                     "runcmd",
                     [
                         "apt autoremove --purge --yes lxd lxd-client lxcfs",
-                        "snap install lxd --channel=4.0",
+                        "snap install lxd --channel=latest",
+                        "snap refresh lxd --channel=latest",
                         f'lxd init --auto --network-address=[::] --trust-password="{password}"',
                     ],
                 ),
diff --git a/src/metadataserver/vendor_data.py b/src/metadataserver/vendor_data.py
index dabf7e1..931e890 100644
--- a/src/metadataserver/vendor_data.py
+++ b/src/metadataserver/vendor_data.py
@@ -177,13 +177,14 @@ def generate_kvm_pod_configuration(node):
             key=LXD_PASSWORD_METADATA_KEY,
             defaults={"value": password},
         )
-        # when installing LXD, make sure no deb packages conflict with the snap
-        # installation. If the snap is not already installed (as in bionic, install
-        # 4.0 which is enough for features required by MAAS). If it's already
-        # installed (as in focal), just keep the existing version.
+        # When installing LXD, ensure no deb packages are installed, since they
+        # would conflict with the snap. Also, ensure that the snap version is
+        # the latest, since MAAS requires features not present in the one
+        # installed by default in Focal.
         yield "runcmd", [
             "apt autoremove --purge --yes lxd lxd-client lxcfs",
-            "snap install lxd --channel=4.0",
+            "snap install lxd --channel=latest",
+            "snap refresh lxd --channel=latest",
             f'lxd init --auto --network-address=[::] --trust-password="{password}"',
         ]