[Backport 3.0] Increase default http.max_header_size to 16kb (#18061)

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

Add change log

Remove duplicate line

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(cherry picked from commit 6afec2a)
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* Update CHANGELOG.md

Signed-off-by: Ankit Jain <akjain@amazon.com>

---------

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Signed-off-by: Ankit Jain <akjain@amazon.com>
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Co-authored-by: Ankit Jain <akjain@amazon.com>

Author: 3 people

CHANGELOG.md

@@ -9,11 +9,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Unset discovery nodes for every transport node actions request ([#17682](https://github.com/opensearch-project/OpenSearch/pull/17682))
 
 ### Changed
+- Change the default max header size from 8KB to 16KB. ([#18024](https://github.com/opensearch-project/OpenSearch/pull/18024))
 
 ### Dependencies
 
-### Changed
-
 ### Deprecated
 
 ### Removed

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(