diff --git a/changelog/unreleased/SOLR-18317.yml b/changelog/unreleased/SOLR-18317.yml
new file mode 100644
index 000000000000..03d74711b8e4
--- /dev/null
+++ b/changelog/unreleased/SOLR-18317.yml
@@ -0,0 +1,7 @@
+title: Admin UI no longer sends nodes=all in standalone mode.
+type: fixed
+authors:
+ - name: Nick Shanin
+links:
+ - name: SOLR-18317
+ url: https://issues.apache.org/jira/browse/SOLR-18317
diff --git a/solr/webapp/src/test/org/apache/solr/webapp/AdminUiLoggingStandaloneTest.java b/solr/webapp/src/test/org/apache/solr/webapp/AdminUiLoggingStandaloneTest.java
new file mode 100644
index 000000000000..548d2d5326de
--- /dev/null
+++ b/solr/webapp/src/test/org/apache/solr/webapp/AdminUiLoggingStandaloneTest.java
@@ -0,0 +1,103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.solr.webapp;
+
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Map;
+import org.apache.solr.common.util.NamedList;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.openqa.selenium.By;
+import org.openqa.selenium.WebElement;
+
+/**
+ * Tests the log-level editor on a standalone (user-managed) node.
+ *
+ *
SOLR-18317: the UI used to unconditionally send {@code nodes=all} to {@code
+ * /admin/info/logging}, a parameter that only makes sense in SolrCloud mode (it broadcasts the
+ * level change to every live node) and used to NPE server-side without a {@code ZkController}. This
+ * exercises the fixed {@code LoggingLevelController.setLevel} against a real standalone node, where
+ * the mapping test coverage ({@code AdminUiLoggingScreenTest}) only ever runs against a SolrCloud
+ * cluster.
+ */
+public class AdminUiLoggingStandaloneTest extends AdminUiStandaloneTestBase {
+
+ @BeforeClass
+ public static void startStandaloneNode() throws Exception {
+ Path home = buildStandaloneHome("collection1");
+ standaloneJetty = startStandaloneJetty(home);
+ baseUrl = standaloneJetty.getBaseUrl().toString();
+ }
+
+ @AfterClass
+ public static void stopStandaloneNode() throws Exception {
+ if (standaloneJetty != null) {
+ standaloneJetty.stop();
+ standaloneJetty = null;
+ }
+ }
+
+ @Test
+ public void testChangeLogLevelViaUi() throws Exception {
+ String logger = "org.apache.solr.core";
+ openPage("~logging/level", By.id("loggingtree"));
+
+ WebElement anchor =
+ waitFor(By.cssSelector("#loggingtree a.jstree-anchor[title='" + logger + "']"));
+ anchor.click();
+ click(By.xpath("//li[a/@title='" + logger + "']//a[normalize-space()='WARN']"));
+ assertLoggerLevel(logger, "WARN");
+
+ // revert to unset; the logger then reports the inherited level with set=false
+ click(By.cssSelector("#loggingtree a.jstree-anchor[title='" + logger + "']"));
+ click(By.xpath("//li[a/@title='" + logger + "']//a[normalize-space()='UNSET']"));
+ assertLoggerLevel(logger, null);
+ assertNoSevereConsoleErrors();
+ }
+
+ /**
+ * Asserts the level a logger was explicitly set to, or with {@code expectedLevel} null, that the
+ * logger has no explicit level (it then reports the inherited effective level with set=false).
+ *
+ *
Before SOLR-18317, the hardcoded {@code nodes=all} param made this request NPE server-side
+ * in standalone mode, so the UI's success callback (and thus {@code $scope.refresh()}) never ran;
+ * this would time out here rather than observing the new level.
+ */
+ @SuppressWarnings("unchecked")
+ private void assertLoggerLevel(String logger, String expectedLevel) throws Exception {
+ waitUntil(
+ "logger " + logger + " has level " + (expectedLevel == null ? "(unset)" : expectedLevel),
+ () -> {
+ try {
+ NamedList