Update testing docs

Signed-off-by: c3y1huang <[email protected]>

integration/test_zone.html

@@ -39,6 +39,9 @@ <h1 class="title">Module <code>tests.test_zone</code></h1>
 from common import cleanup_node_disks
 from common import get_self_host_id
 
+from common import get_update_disks
+from common import update_node_disks
+
 from common import create_and_wait_pod
 from common import create_pv_for_volume
 from common import create_pvc_for_volume
@@ -610,6 +613,88 @@ <h1 class="title">Module <code>tests.test_zone</code></h1>
     assert_replica_count(is_stable=True)
 
 
+def test_replica_auto_balance_when_no_storage_available_in_zone(client, core_api, volume_name):  # NOQA
+    &#34;&#34;&#34;
+    Scenario: replica auto-balance when there is no storage available on nodes
+              in a zone.
+
+    Issue: https://github.com/longhorn/longhorn/issues/6671
+
+    Given `replica-soft-anti-affinity` setting is `true`.
+    And node-1 is in zone-1.
+        node-2 is in zone-2.
+        node-3 is in zone-3.
+    And fill up the storage on node-3.
+    And create a volume with 3 replicas.
+    And attach the volume to test pod node.
+    And 3 replicas running in zone-1 and zone-2.
+        0 replicas running in zone-3.
+
+    When set `replica-auto-balance` to `best-effort`.
+
+    Then 3 replicas running in zone-1 and zone-2.
+         0 replicas running in zone-3.
+    And replica count remains stable across zones and nodes.
+    &#34;&#34;&#34;
+    # Set `replica-soft-anti-affinity` to `true`.
+    update_setting(client, SETTING_REPLICA_NODE_SOFT_ANTI_AFFINITY, &#34;true&#34;)
+
+    # Assign nodes to respective zones
+    node1, node2, node3 = client.list_node()
+    set_k8s_node_zone_label(core_api, node1.name, ZONE1)
+    set_k8s_node_zone_label(core_api, node2.name, ZONE2)
+    set_k8s_node_zone_label(core_api, node3.name, ZONE3)
+    wait_longhorn_node_zone_updated(client)
+
+    # Fill up the storage on node 3
+    for _, disk in node3.disks.items():
+        disk.storageReserved = disk.storageMaximum
+
+    update_disks = get_update_disks(node3.disks)
+    update_node_disks(client, node3.name, disks=update_disks, retry=True)
+
+    # Create a volume with 3 replicas
+    num_of_replicas = 3
+    volume = client.create_volume(name=volume_name,
+                                  numberOfReplicas=num_of_replicas)
+
+    # Wait for ht evolume to detach and attache it to the test pod node
+    volume = wait_for_volume_detached(client, volume_name)
+    volume.attach(hostId=get_self_host_id())
+
+    # Define a function to assert replica count
+    def assert_replica_count(is_stable=False):
+        for _ in range(RETRY_COUNTS):
+            time.sleep(RETRY_INTERVAL)
+
+            zone3_replica_count = get_zone_replica_count(
+                client, volume_name, ZONE3, chk_running=True)
+            assert zone3_replica_count == 0
+
+            total_replica_count = \
+                get_zone_replica_count(
+                    client, volume_name, ZONE1, chk_running=True) + \
+                get_zone_replica_count(
+                    client, volume_name, ZONE2, chk_running=True)
+
+            if is_stable:
+                assert total_replica_count == num_of_replicas
+            elif total_replica_count == num_of_replicas:
+                break
+
+        assert total_replica_count == 3
+
+    # Perform the initial assertion to ensure the replica count is as expected
+    assert_replica_count()
+
+    # Update the replica-auto-balance setting to `best-effort`
+    update_setting(client, SETTING_REPLICA_AUTO_BALANCE, &#34;best-effort&#34;)
+
+    # Perform the final assertion to ensure the replica count is as expected,
+    # and stable after the setting update
+    assert_replica_count(is_stable=True)
+
+
 def test_replica_auto_balance_when_replica_on_unschedulable_node(client, core_api, volume_name, request):  # NOQA
     &#34;&#34;&#34;
     Scenario: replica auto-balance when replica already running on
@@ -1503,6 +1588,112 @@ <h2 class="section-title" id="header-functions">Functions</h2>
     assert_replica_count(is_stable=True)</code></pre>
 </details>
 </dd>
+<dt id="tests.test_zone.test_replica_auto_balance_when_no_storage_available_in_zone"><code class="name flex">
+<span>def <span class="ident">test_replica_auto_balance_when_no_storage_available_in_zone</span></span>(<span>client, core_api, volume_name)</span>
+</code></dt>
+<dd>
+<div class="desc"><p>Scenario: replica auto-balance when there is no storage available on nodes
+in a zone.</p>
+<p>Issue: <a href="https://github.com/longhorn/longhorn/issues/6671">https://github.com/longhorn/longhorn/issues/6671</a></p>
+<p>Given <code>replica-soft-anti-affinity</code> setting is <code>true</code>.
+And node-1 is in zone-1.
+node-2 is in zone-2.
+node-3 is in zone-3.
+And fill up the storage on node-3.
+And create a volume with 3 replicas.
+And attach the volume to test pod node.
+And 3 replicas running in zone-1 and zone-2.
+0 replicas running in zone-3.</p>
+<p>When set <code>replica-auto-balance</code> to <code>best-effort</code>.</p>
+<p>Then 3 replicas running in zone-1 and zone-2.
+0 replicas running in zone-3.
+And replica count remains stable across zones and nodes.</p></div>
+<details class="source">
+<summary>
+<span>Expand source code</span>
+</summary>
+<pre><code class="python">def test_replica_auto_balance_when_no_storage_available_in_zone(client, core_api, volume_name):  # NOQA
+    &#34;&#34;&#34;
+    Scenario: replica auto-balance when there is no storage available on nodes
+              in a zone.
+
+    Issue: https://github.com/longhorn/longhorn/issues/6671
+
+    Given `replica-soft-anti-affinity` setting is `true`.
+    And node-1 is in zone-1.
+        node-2 is in zone-2.
+        node-3 is in zone-3.
+    And fill up the storage on node-3.
+    And create a volume with 3 replicas.
+    And attach the volume to test pod node.
+    And 3 replicas running in zone-1 and zone-2.
+        0 replicas running in zone-3.
+
+    When set `replica-auto-balance` to `best-effort`.
+
+    Then 3 replicas running in zone-1 and zone-2.
+         0 replicas running in zone-3.
+    And replica count remains stable across zones and nodes.
+    &#34;&#34;&#34;
+    # Set `replica-soft-anti-affinity` to `true`.
+    update_setting(client, SETTING_REPLICA_NODE_SOFT_ANTI_AFFINITY, &#34;true&#34;)
+
+    # Assign nodes to respective zones
+    node1, node2, node3 = client.list_node()
+    set_k8s_node_zone_label(core_api, node1.name, ZONE1)
+    set_k8s_node_zone_label(core_api, node2.name, ZONE2)
+    set_k8s_node_zone_label(core_api, node3.name, ZONE3)
+    wait_longhorn_node_zone_updated(client)
+
+    # Fill up the storage on node 3
+    for _, disk in node3.disks.items():
+        disk.storageReserved = disk.storageMaximum
+
+    update_disks = get_update_disks(node3.disks)
+    update_node_disks(client, node3.name, disks=update_disks, retry=True)
+
+    # Create a volume with 3 replicas
+    num_of_replicas = 3
+    volume = client.create_volume(name=volume_name,
+                                  numberOfReplicas=num_of_replicas)
+
+    # Wait for ht evolume to detach and attache it to the test pod node
+    volume = wait_for_volume_detached(client, volume_name)
+    volume.attach(hostId=get_self_host_id())
+
+    # Define a function to assert replica count
+    def assert_replica_count(is_stable=False):
+        for _ in range(RETRY_COUNTS):
+            time.sleep(RETRY_INTERVAL)
+
+            zone3_replica_count = get_zone_replica_count(
+                client, volume_name, ZONE3, chk_running=True)
+            assert zone3_replica_count == 0
+
+            total_replica_count = \
+                get_zone_replica_count(
+                    client, volume_name, ZONE1, chk_running=True) + \
+                get_zone_replica_count(
+                    client, volume_name, ZONE2, chk_running=True)
+
+            if is_stable:
+                assert total_replica_count == num_of_replicas
+            elif total_replica_count == num_of_replicas:
+                break
+
+        assert total_replica_count == 3
+
+    # Perform the initial assertion to ensure the replica count is as expected
+    assert_replica_count()
+
+    # Update the replica-auto-balance setting to `best-effort`
+    update_setting(client, SETTING_REPLICA_AUTO_BALANCE, &#34;best-effort&#34;)
+
+    # Perform the final assertion to ensure the replica count is as expected,
+    # and stable after the setting update
+    assert_replica_count(is_stable=True)</code></pre>
+</details>
+</dd>
 <dt id="tests.test_zone.test_replica_auto_balance_when_replica_on_unschedulable_node"><code class="name flex">
 <span>def <span class="ident">test_replica_auto_balance_when_replica_on_unschedulable_node</span></span>(<span>client, core_api, volume_name, request)</span>
 </code></dt>
@@ -2548,6 +2739,7 @@ <h1>Index</h1>
 <li><code><a title="tests.test_zone.test_replica_auto_balance_node_duplicates_in_multiple_zones" href="#tests.test_zone.test_replica_auto_balance_node_duplicates_in_multiple_zones">test_replica_auto_balance_node_duplicates_in_multiple_zones</a></code></li>
 <li><code><a title="tests.test_zone.test_replica_auto_balance_should_respect_node_selector" href="#tests.test_zone.test_replica_auto_balance_should_respect_node_selector">test_replica_auto_balance_should_respect_node_selector</a></code></li>
 <li><code><a title="tests.test_zone.test_replica_auto_balance_when_disabled_disk_scheduling_in_zone" href="#tests.test_zone.test_replica_auto_balance_when_disabled_disk_scheduling_in_zone">test_replica_auto_balance_when_disabled_disk_scheduling_in_zone</a></code></li>
+<li><code><a title="tests.test_zone.test_replica_auto_balance_when_no_storage_available_in_zone" href="#tests.test_zone.test_replica_auto_balance_when_no_storage_available_in_zone">test_replica_auto_balance_when_no_storage_available_in_zone</a></code></li>
 <li><code><a title="tests.test_zone.test_replica_auto_balance_when_replica_on_unschedulable_node" href="#tests.test_zone.test_replica_auto_balance_when_replica_on_unschedulable_node">test_replica_auto_balance_when_replica_on_unschedulable_node</a></code></li>
 <li><code><a title="tests.test_zone.test_replica_auto_balance_zone_best_effort" href="#tests.test_zone.test_replica_auto_balance_zone_best_effort">test_replica_auto_balance_zone_best_effort</a></code></li>
 <li><code><a title="tests.test_zone.test_replica_auto_balance_zone_best_effort_with_data_locality" href="#tests.test_zone.test_replica_auto_balance_zone_best_effort_with_data_locality">test_replica_auto_balance_zone_best_effort_with_data_locality</a></code></li>