Return-Path: Delivered-To: apmail-hadoop-core-user-archive@www.apache.org Received: (qmail 57121 invoked from network); 30 Oct 2008 02:15:19 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.2) by minotaur.apache.org with SMTP; 30 Oct 2008 02:15:19 -0000 Received: (qmail 98339 invoked by uid 500); 30 Oct 2008 02:15:19 -0000 Delivered-To: apmail-hadoop-core-user-archive@hadoop.apache.org Received: (qmail 98297 invoked by uid 500); 30 Oct 2008 02:15:19 -0000 Mailing-List: contact core-user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: core-user@hadoop.apache.org Delivered-To: mailing list core-user@hadoop.apache.org Received: (qmail 98285 invoked by uid 99); 30 Oct 2008 02:15:19 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 29 Oct 2008 19:15:19 -0700 X-ASF-Spam-Status: No, hits=-0.0 required=10.0 tests=SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: local policy) Received: from [208.88.241.29] (HELO saturn.datasyncintra.net) (208.88.241.29) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 30 Oct 2008 02:14:05 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by saturn.datasyncintra.net (Postfix) with ESMTP id EDE82479690 for ; Wed, 29 Oct 2008 21:14:14 -0500 (CDT) X-Virus-Scanned: amavisd-new at X-Spam-Score: 1.885 X-Spam-Level: * Received: from saturn.datasyncintra.net ([127.0.0.1]) by localhost (saturn.datasyncintra.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id lY+5gr+ehx52 for ; Wed, 29 Oct 2008 21:14:14 -0500 (CDT) Received: from [192.168.0.130] (pool-96-237-173-165.bstnma.fios.verizon.net [96.237.173.165]) by saturn.datasyncintra.net (Postfix) with ESMTP id 6F314479443 for ; Wed, 29 Oct 2008 21:14:14 -0500 (CDT) Message-Id: <03FD4326-31BD-469A-B7CC-E6151615A412@dataxu.com> From: Scott Whitecross To: core-user@hadoop.apache.org Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v929.2) Subject: Debugging / Logging in Hadoop? Date: Wed, 29 Oct 2008 22:14:12 -0400 X-Mailer: Apple Mail (2.929.2) X-Virus-Checked: Checked by ClamAV on apache.org X-Old-Spam-Flag: NO X-Old-Spam-Status: No, score=1.885 tagged_above=-10 required=3.2 tests=[AWL=0.001, BAYES_50=0.001, FH_HOST_EQ_VERIZON_P=0.001, RCVD_IN_PBL=0.905, RCVD_IN_SORBS_DUL=0.877, RDNS_DYNAMIC=0.1] I'm curious to what the best method for debugging and logging in Hadoop? I put together a small cluster today and a simple application to process log files. While it worked well, I had trouble trying to get logging information out. Is there any way to attach a debugger, or get log4j to write a log file? I tried setting up a Logger in the class I used for the map/reduce, but I had no luck. Thanks.