diff --git a/docs/core-migration-guide.md b/docs/core-migration-guide.md
index 1d55c4c3e66d..d7ff6b1509ce 100644
--- a/docs/core-migration-guide.md
+++ b/docs/core-migration-guide.md
@@ -22,6 +22,10 @@ license: |
 * Table of contents
 {:toc}
 
+## Upgrading from Core 4.1 to 4.2
+
+- Since Spark 4.2, Spark will allocate executor pods with a batch size of `20`. To restore the legacy behavior, you can set `spark.kubernetes.allocation.batch.size` to `10`.
+
 ## Upgrading from Core 4.0 to 4.1
 
 - Since Spark 4.1, Spark Master deamon provides REST API by default. To restore the behavior before Spark 4.1, you can set `spark.master.rest.enabled` to `false`.
diff --git a/docs/running-on-kubernetes.md b/docs/running-on-kubernetes.md
index ababe38e4e25..eac8d6a5d1ec 100644
--- a/docs/running-on-kubernetes.md
+++ b/docs/running-on-kubernetes.md
@@ -685,7 +685,7 @@ See the [configuration page](configuration.html) for information on Spark config
 </tr>
 <tr>
   <td><code>spark.kubernetes.allocation.batch.size</code></td>
-  <td><code>10</code></td>
+  <td><code>20</code></td>
   <td>
     Number of pods to launch at once in each round of executor pod allocation.
   </td>
diff --git a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala
index 1fb214c87c53..3f131874fc5e 100644
--- a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala
+++ b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala
@@ -487,7 +487,7 @@ private[spark] object Config extends Logging {
       .version("2.3.0")
       .intConf
       .checkValue(value => value > 0, "Allocation batch size should be a positive integer")
-      .createWithDefault(10)
+      .createWithDefault(20)
 
   val KUBERNETES_ALLOCATION_BATCH_DELAY =
     ConfigBuilder("spark.kubernetes.allocation.batch.delay")