Update "instances" fixture, removing the k8s snap when cleaning up

At the moment, the "instances" fixture removes the test instances
without uninstalling the k8s snap. In case of LXD instances, this
can leak certain resources on the host, for example loopback
devices.

We'll update the fixture to remove the k8s snap as part of the
instance cleanup procedure.

tests/integration/tests/conftest.py

@@ -192,6 +192,8 @@ def instances(
             LOG.debug("Generating inspection reports for test instances")
             _generate_inspection_report(h, instance.id)
 
+        util.remove_k8s_snap(instance)
+
         h.delete_instance(instance.id)
 
 

tests/integration/tests/test_cleanup.py

@@ -5,7 +5,7 @@
 from typing import List
 
 import pytest
-from test_util import config, harness, util
+from test_util import harness, util
 
 LOG = logging.getLogger(__name__)
 
@@ -16,40 +16,4 @@ def test_node_cleanup(instances: List[harness.Instance]):
     util.wait_for_dns(instance)
     util.wait_for_network(instance)
 
-    LOG.info("Uninstall k8s...")
-    instance.exec(["snap", "remove", config.SNAP_NAME, "--purge"])
-
-    LOG.info("Waiting for shims to go away...")
-    util.stubbornly(retries=5, delay_s=5).on(instance).until(
-        lambda p: all(
-            x not in p.stdout.decode()
-            for x in ["containerd-shim", "cilium", "coredns", "/pause"]
-        )
-    ).exec(["ps", "-fea"])
-
-    LOG.info("Waiting for kubelet and containerd mounts to go away...")
-    util.stubbornly(retries=5, delay_s=5).on(instance).until(
-        lambda p: all(
-            x not in p.stdout.decode()
-            for x in ["/var/lib/kubelet/pods", "/run/containerd/io.containerd"]
-        )
-    ).exec(["mount"])
-
-    # NOTE(neoaggelos): Temporarily disable this as it fails on strict.
-    # For details, `snap changes` then `snap change $remove_k8s_snap_change`.
-    # Example output follows:
-    #
-    # 2024-02-23T14:10:42Z ERROR ignoring failure in hook "remove":
-    # -----
-    # ...
-    # ip netns delete cni-UUID1
-    # Cannot remove namespace file "/run/netns/cni-UUID1": Device or resource busy
-    # ip netns delete cni-UUID2
-    # Cannot remove namespace file "/run/netns/cni-UUID2": Device or resource busy
-    # ip netns delete cni-UUID3
-    # Cannot remove namespace file "/run/netns/cni-UUID3": Device or resource busy
-
-    # LOG.info("Waiting for CNI network namespaces to go away...")
-    # util.stubbornly(retries=5, delay_s=5).on(instance).until(
-    #     lambda p: "cni-" not in p.stdout.decode()
-    # ).exec(["ip", "netns", "list"])
+    util.remove_k8s_snap(instance)

tests/integration/tests/test_util/util.py

@@ -185,6 +185,46 @@ def setup_k8s_snap(
         instance.exec(["/snap/k8s/current/k8s/hack/init.sh"], stdout=subprocess.DEVNULL)
 
 
+def remove_k8s_snap(instance: harness.Instance):
+    LOG.info("Uninstall k8s...")
+    instance.exec(["snap", "remove", config.SNAP_NAME, "--purge"])
+
+    LOG.info("Waiting for shims to go away...")
+    stubbornly(retries=5, delay_s=5).on(instance).until(
+        lambda p: all(
+            x not in p.stdout.decode()
+            for x in ["containerd-shim", "cilium", "coredns", "/pause"]
+        )
+    ).exec(["ps", "-fea"])
+
+    LOG.info("Waiting for kubelet and containerd mounts to go away...")
+    stubbornly(retries=5, delay_s=5).on(instance).until(
+        lambda p: all(
+            x not in p.stdout.decode()
+            for x in ["/var/lib/kubelet/pods", "/run/containerd/io.containerd"]
+        )
+    ).exec(["mount"])
+
+    # NOTE(neoaggelos): Temporarily disable this as it fails on strict.
+    # For details, `snap changes` then `snap change $remove_k8s_snap_change`.
+    # Example output follows:
+    #
+    # 2024-02-23T14:10:42Z ERROR ignoring failure in hook "remove":
+    # -----
+    # ...
+    # ip netns delete cni-UUID1
+    # Cannot remove namespace file "/run/netns/cni-UUID1": Device or resource busy
+    # ip netns delete cni-UUID2
+    # Cannot remove namespace file "/run/netns/cni-UUID2": Device or resource busy
+    # ip netns delete cni-UUID3
+    # Cannot remove namespace file "/run/netns/cni-UUID3": Device or resource busy
+
+    # LOG.info("Waiting for CNI network namespaces to go away...")
+    # stubbornly(retries=5, delay_s=5).on(instance).until(
+    #     lambda p: "cni-" not in p.stdout.decode()
+    # ).exec(["ip", "netns", "list"])
+
+
 def wait_until_k8s_ready(
     control_node: harness.Instance,
     instances: List[harness.Instance],