From d736ea37877bb6fc901bf88dcb3033cda08246e8 Mon Sep 17 00:00:00 2001
From: Mariusz Jozala <mariusz.jozala@elastic.co>
Date: Wed, 20 Aug 2025 11:09:17 +0200
Subject: [PATCH 1/2] Set default processor allocation for test clusters

Setting the number of processors available for node to adequately size
thread pools.
Related to #130612
---
 .../gradle/internal/InternalTestClustersPlugin.java    | 10 +++++++---
 .../test/cluster/local/DefaultSettingsProvider.java    |  4 ++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalTestClustersPlugin.java b/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalTestClustersPlugin.java
index f1b96016286df..dda0f3b3ca015 100644
--- a/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalTestClustersPlugin.java
+++ b/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalTestClustersPlugin.java
@@ -34,11 +34,15 @@ public void apply(Project project) {
                 || buildParams.getBwcVersions().unreleasedInfo(version) == null
         );
 
+        NamedDomainObjectContainer<ElasticsearchCluster> testClusters = (NamedDomainObjectContainer<ElasticsearchCluster>) project
+            .getExtensions()
+            .getByName(TestClustersPlugin.EXTENSION_NAME);
         if (shouldConfigureTestClustersWithOneProcessor()) {
-            NamedDomainObjectContainer<ElasticsearchCluster> testClusters = (NamedDomainObjectContainer<ElasticsearchCluster>) project
-                .getExtensions()
-                .getByName(TestClustersPlugin.EXTENSION_NAME);
             testClusters.configureEach(elasticsearchCluster -> elasticsearchCluster.setting("node.processors", "1"));
+        } else {
+            // Limit the number of allocated processors for all nodes in the cluster by default.
+            // This is to ensure that the tests run consistently across different environments.
+            testClusters.configureEach(elasticsearchCluster -> elasticsearchCluster.setting("node.processors", "2"));
         }
     }
 
diff --git a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/DefaultSettingsProvider.java b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/DefaultSettingsProvider.java
index b53f4ece46134..2fdf0df41736a 100644
--- a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/DefaultSettingsProvider.java
+++ b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/DefaultSettingsProvider.java
@@ -42,6 +42,10 @@ public Map<String, String> get(LocalNodeSpec nodeSpec) {
             }
         }
 
+        // Limit the number of allocated processors for all nodes in the cluster by default.
+        // This is to ensure that the tests run consistently across different environments.
+        settings.put("node.processors", "2");
+
         // Default the watermarks to absurdly low to prevent the tests from failing on nodes without enough disk space
         settings.put("cluster.routing.allocation.disk.watermark.low", "1b");
         settings.put("cluster.routing.allocation.disk.watermark.high", "1b");

From b36bf483e49eb9a1589652e8a22b474bfaee94b6 Mon Sep 17 00:00:00 2001
From: Mariusz Jozala <mariusz.jozala@elastic.co>
Date: Wed, 20 Aug 2025 12:23:46 +0200
Subject: [PATCH 2/2] Refactor processor allocation logic for test clusters

---
 .../gradle/internal/InternalTestClustersPlugin.java   | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalTestClustersPlugin.java b/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalTestClustersPlugin.java
index dda0f3b3ca015..2a2e1ea28d1ec 100644
--- a/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalTestClustersPlugin.java
+++ b/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalTestClustersPlugin.java
@@ -37,13 +37,10 @@ public void apply(Project project) {
         NamedDomainObjectContainer<ElasticsearchCluster> testClusters = (NamedDomainObjectContainer<ElasticsearchCluster>) project
             .getExtensions()
             .getByName(TestClustersPlugin.EXTENSION_NAME);
-        if (shouldConfigureTestClustersWithOneProcessor()) {
-            testClusters.configureEach(elasticsearchCluster -> elasticsearchCluster.setting("node.processors", "1"));
-        } else {
-            // Limit the number of allocated processors for all nodes in the cluster by default.
-            // This is to ensure that the tests run consistently across different environments.
-            testClusters.configureEach(elasticsearchCluster -> elasticsearchCluster.setting("node.processors", "2"));
-        }
+        // Limit the number of allocated processors for all nodes to 2 in the cluster by default.
+        // This is to ensure that the tests run consistently across different environments.
+        String processorCount = shouldConfigureTestClustersWithOneProcessor() ? "1" : "2";
+        testClusters.configureEach(elasticsearchCluster -> elasticsearchCluster.setting("node.processors", processorCount));
     }
 
     private boolean shouldConfigureTestClustersWithOneProcessor() {