Enhances the longhorn integration test (#7)

The integration test now also waits for the "driver.longhorn.io"
annotation to be added to the node. If this is added, it means that the
Longhorn CSI plugin successfully registered.

The integration now spawns an NGINX pod with a PVC, which should be
satisfied by Longhorn.

tests/integration/test_longhorn_in_helm_chart.py

@@ -4,7 +4,9 @@
 
 import json
 import logging
+import pathlib
 import sys
+import time
 
 import pytest
 from k8s_test_harness import harness
@@ -15,12 +17,18 @@
 LOG.addHandler(logging.FileHandler(f"{__name__}.log"))
 LOG.addHandler(logging.StreamHandler(sys.stdout))
 
+DIR = pathlib.Path(__file__).absolute().parent
+TEMPLATES_DIR = DIR / ".." / "templates"
+
+CSI_VOLUME_ANNOTATION = "csi.volume.kubernetes.io/nodeid"
+LONGHORN_CSI_ANNOTATION_VALUE = "driver.longhorn.io"
 
 IMAGE_VERSIONS = ["v1.7.0"]
 # TODO(aznashwan): enable previous version testing too:
 # IMAGE_VERSIONS = ["v1.6.2", "v1.7.0"]
 CHART_RELEASE_URL = "https://github.com/longhorn/charts/releases/download/longhorn-1.7.0/longhorn-1.7.0.tgz"
 INSTALL_NAME = "longhorn"
+INSTALL_NS = "longhorn"
 
 LONGHORN_AUX_IMAGES_VERSION_MAP = {
     # https://github.com/longhorn/longhorn/releases/download/v1.7.0/longhorn-images.txt
@@ -57,6 +65,27 @@
 }
 
 
+def _wait_for_node_annotation(instance, annotation, value):
+    escaped_annotation = annotation.translate(str.maketrans({".": "\\.", "/": "\\/"}))
+    jsonpath = f"jsonpath='{{.items[0].metadata.annotations.{escaped_annotation}}}'"
+
+    annotated = False
+    for i in range(10):
+        process = instance.exec(
+            ["k8s", "kubectl", "get", "nodes", "-o", jsonpath],
+            capture_output=True,
+            text=True,
+        )
+
+        if value in process.stdout:
+            annotated = True
+            break
+
+        time.sleep(5)
+
+    assert annotated, f"Expected node to have annotation '{annotation}={value}'."
+
+
 @pytest.mark.parametrize("image_version", IMAGE_VERSIONS)
 def test_longhorn_helm_chart_deployment(
     function_instance: harness.Instance, image_version: str
@@ -99,6 +128,9 @@ def test_longhorn_helm_chart_deployment(
         "install",
         INSTALL_NAME,
         CHART_RELEASE_URL,
+        "--namespace",
+        INSTALL_NS,
+        "--create-namespace",
     ]
     helm_command.extend(all_chart_value_overrides_args)
 
@@ -116,6 +148,7 @@ def test_longhorn_helm_chart_deployment(
         k8s_util.wait_for_daemonset(
             function_instance,
             daemonset,
+            INSTALL_NS,
             **retry_kwargs,
         )
 
@@ -131,6 +164,44 @@ def test_longhorn_helm_chart_deployment(
         k8s_util.wait_for_deployment(
             function_instance,
             deployment,
+            INSTALL_NS,
             condition=constants.K8S_CONDITION_AVAILABLE,
             **retry_kwargs,
         )
+
+    # Wait until the node gets annotated with driver.longhorn.io, meaning that the Longhorn CSI
+    # plugin was successfully registered.
+    _wait_for_node_annotation(
+        function_instance, CSI_VOLUME_ANNOTATION, LONGHORN_CSI_ANNOTATION_VALUE
+    )
+
+    # Deploy an nginx Pod with a PVC, which should be satisfied by Longhorn.
+    function_instance.exec(
+        ["k8s", "kubectl", "apply", "-f", "-"],
+        input=pathlib.Path(TEMPLATES_DIR / "nginx-pod.yaml").read_bytes(),
+    )
+
+    # Expect the Pod to become ready, and that it has the volume attached.
+    k8s_util.wait_for_resource(
+        function_instance,
+        "pod",
+        "nginx-longhorn-example",
+        condition=constants.K8S_CONDITION_READY,
+    )
+
+    process = function_instance.exec(
+        [
+            "k8s",
+            "kubectl",
+            "exec",
+            "nginx-longhorn-example",
+            "--",
+            "bash",
+            "-c",
+            "findmnt /var/www -o FSTYPE,TARGET,SOURCE",
+        ],
+        capture_output=True,
+        text=True,
+    )
+
+    assert "ext4   /var/www /dev/longhorn/pvc-" in process.stdout

tests/templates/nginx-pod.yaml

@@ -0,0 +1,28 @@
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: longhorn-pvc
+spec:
+  accessModes:
+    - ReadWriteOnce
+  storageClassName: longhorn
+  resources:
+    requests:
+      storage: 2Gi
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx-longhorn-example
+spec:
+  containers:
+    - name: nginx
+      image: nginx
+      volumeMounts:
+      - name: longhorn-pvc
+        mountPath: /var/www
+        readOnly: false
+  volumes:
+    - name: longhorn-pvc
+      persistentVolumeClaim:
+        claimName: longhorn-pvc