Increase default http.max_header_size to 16kb (#18024)

Add change log



Remove duplicate line

Signed-off-by: 10000-ki <[email protected]>

Author: 10000-ki

CHANGELOG.md

@@ -10,13 +10,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Implement parallel shard refresh behind cluster settings ([#17782](https://github.com/opensearch-project/OpenSearch/pull/17782))
 
 ### Changed
+- Change the default max header size from 8KB to 16KB. ([#18024](https://github.com/opensearch-project/OpenSearch/pull/18024))
 
 ### Dependencies
 - Bump `com.google.code.gson:gson` from 2.12.1 to 2.13.0 ([#17923](https://github.com/opensearch-project/OpenSearch/pull/17923))
 - Bump `com.github.spotbugs:spotbugs-annotations` from 4.9.0 to 4.9.3 ([#17922](https://github.com/opensearch-project/OpenSearch/pull/17922))
 - Bump `com.microsoft.azure:msal4j` from 1.18.0 to 1.20.0 ([#17925](https://github.com/opensearch-project/OpenSearch/pull/17925))
 
-### Changed
+### Dependencies
 
 ### Deprecated
 

server/src/main/java/org/opensearch/http/HttpTransportSettings.java

@@ -151,7 +151,7 @@ public final class HttpTransportSettings {
     );
     public static final Setting<ByteSizeValue> SETTING_HTTP_MAX_HEADER_SIZE = Setting.byteSizeSetting(
         "http.max_header_size",
-        new ByteSizeValue(8, ByteSizeUnit.KB),
+        new ByteSizeValue(16, ByteSizeUnit.KB),
         Property.NodeScope
     );
     public static final Setting<Integer> SETTING_HTTP_MAX_WARNING_HEADER_COUNT = intSetting(