[
https://issues.apache.org/jira/browse/HADOOP-19447?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17939560#comment-17939560
]
ASF GitHub Bot commented on HADOOP-19447:
-----------------------------------------
yangjiandan commented on code in PR #7527:
URL: https://github.com/apache/hadoop/pull/7527#discussion_r2020464185
##########
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/CommonConfigurationKeys.java:
##########
@@ -243,6 +243,11 @@ public class CommonConfigurationKeys extends
CommonConfigurationKeysPublic {
"hadoop.security.token.service.use_ip";
public static final boolean HADOOP_SECURITY_TOKEN_SERVICE_USE_IP_DEFAULT =
true;
+ public static final String
+ HADOOP_SECURITY_HOSTNAME_CACHE_EXPIRE_INTERVAL_SECONDS =
+ "hadoop.security.hostname.cache.expire-interval.seconds";
Review Comment:
Good point! I agree this is a useful config to expose.
I'll update the PR to include it in the core-default.xml with 0 as the
default value to maintain backword compatibility.
> Add Caching Mechanism to HostResolver to Avoid Redundant Hostname Resolutions
> -----------------------------------------------------------------------------
>
> Key: HADOOP-19447
> URL: https://issues.apache.org/jira/browse/HADOOP-19447
> Project: Hadoop Common
> Issue Type: New Feature
> Components: common, yarn
> Reporter: Jiandan Yang
> Priority: Major
> Labels: pull-request-available
>
> *Background:*
>
> Currently, the two implementations of
> org.apache.hadoop.security.SecurityUtil.HostResolver, *StandardHostResolver
> and QualifiedHostResolver* in Hadoop performs hostname resolution each time
> it is called. *Each heartbeat between the AM and RM causes the RM to invoke
> the* HostResolver#getByName {*}method once{*}. In large-scale clusters
> running numerous applications, this results in *a high frequency of redundant
> hostname resolutions.*
>
> *Proposal:*
>
> Introduce a caching mechanism in HostResolver to store resolved hostnames for
> a configurable duration. This would:
> •Reduce redundant DNS queries.
> •Improve performance for frequently used hostnames.
> •Allow configuration options for cache size and TTL (Time-to-Live).
>
> *Suggested Implementation:*
> 1.{*}Leverage Existing CachedResolver{*}:
> The NodesListManager.CachedResolver class in Hadoop already implements a
> caching mechanism for hostname resolution. Instead of introducing an entirely
> new solution, we propose *extracting the caching logic from*
> NodesListManager.CachedResolver {*}into a separate reusable utility class{*}.
> 2.{*}Create a Shared Caching Utility{*}:
> •Extract the caching logic from NodesListManager.CachedResolver.
> •Implement a new class, e.g., HostnameCache, and place it in the Hadoop
> Common module to ensure it can be used across different components.
> 3.{*}Integrate{*} HostnameCache with *HostResolver &QualifiedHostResolver*:
> •Modify HostResolver to use HostnameCache for hostname lookups.
> •Update NodesListManager.CachedResolver to use HostnameCache instead of its
> own internal cache.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: common-issues-h...@hadoop.apache.org
