[jira] [Commented] (YARN-11821) Support pattern matching for YARN proxy addresses.

["SUYEON LEE (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/YARN-11821?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17952772#comment-17952772 ] 

SUYEON LEE commented on YARN-11821:
-----------------------------------

[https://github.com/apache/hadoop/pull/7697]

 

> Support pattern matching for YARN proxy addresses.
> --------------------------------------------------
>
>                 Key: YARN-11821
>                 URL: https://issues.apache.org/jira/browse/YARN-11821
>             Project: Hadoop YARN
>          Issue Type: Bug
>          Components: nodemanager, router
>    Affects Versions: 3.4.1
>            Reporter: SUYEON LEE
>            Priority: Major
>         Attachments: 스크린샷 2025-02-20 오후 6.14.27.png
>
>
> *Issue:*
> In a YARN Federation environment utilizing multiple YARN Routers, if a Global Server Load Balancer (GSLB) is used for distributing requests to these Routers _without_ sticky session support, users encounter redirection errors.
> !스크린샷 2025-02-20 오후 6.14.27.png!
> These errors typically manifest when accessing application UIs or logs via the NodeManager's proxy.
> *Problem Details:*
> The root cause of this issue lies in how the NodeManager (NM) resolves the YARN Router address for proxying web requests. The NodeManager uses the {{yarn.web-proxy.address}} configuration property to determine the Router's address. However, this property is designed to accommodate only a single hostname or IP address.
> When a GSLB without sticky sessions distributes requests, an initial request might be routed to Router A, while a subsequent request (e.g., for application logs, proxied by an NM) might be directed by the GSLB to Router B, or the NM might be configured with a specific Router/GSLB VIP that resolves to Router B. If the ApplicationMaster (AM) for the application in question is registered with Router A, Router B may not be able to correctly proxy or redirect the request, leading to errors. The NM's attempt to proxy through an "incorrect" or context-unaware Router (relative to where the AM is known) due to the single-host limitation in {{yarn.web-proxy.address}} results in these failures.
> *Analysis / Root Cause Summary:*
>  # *Environment:* YARN Federation with multiple YARN Routers.
>  # *Load Balancing:* GSLB used without sticky session support, leading to requests for the same session potentially hitting different Routers.
>  # *NM Proxy Mechanism:* NodeManagers use {{yarn.web-proxy.address}} to identify the YARN Router for proxying UI/log requests.
>  # *Configuration Limitation:* {{yarn.web-proxy.address}} supports only a single host, making it incompatible with a multi-Router setup where requests are not sticky.
>  # *Symptom:* Redirection errors occur as the NM may attempt to proxy through a Router that does not have the necessary context for the specific application/AM, or is not the Router the user was initially interacting with via the GSLB.
> *Proposed Solution:*
> To address this limitation, a patch has been developed to introduce *pattern-based address matching for the YARN web proxy functionality.*
> This enhancement will allow {{yarn.web-proxy.address.pattern}} to be configured with a pattern or a list of Routers. The NodeManager's proxy mechanism can then intelligently select or match the appropriate Router address, ensuring that requests are proxied correctly even in a federated environment with multiple Routers and non-sticky load balancing.
> *Goal of the Patch:*
>  * Enable robust YARN web proxying in federated environments with multiple Routers load-balanced by a non-sticky GSLB.
>  * Improve the usability and reliability of accessing application UIs and logs in such configurations.



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