From hdfs-issues-return-263659-archive-asf-public=cust-asf.ponee.io@hadoop.apache.org Tue May 21 06:20:08 2019 Return-Path: X-Original-To: archive-asf-public@cust-asf.ponee.io Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [207.244.88.153]) by mx-eu-01.ponee.io (Postfix) with SMTP id BB14718077F for ; Tue, 21 May 2019 08:20:07 +0200 (CEST) Received: (qmail 68000 invoked by uid 500); 21 May 2019 06:20:01 -0000 Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Delivered-To: mailing list hdfs-issues@hadoop.apache.org Received: (qmail 67894 invoked by uid 99); 21 May 2019 06:20:01 -0000 Received: from mailrelay1-us-west.apache.org (HELO mailrelay1-us-west.apache.org) (209.188.14.139) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 21 May 2019 06:20:01 +0000 Received: from jira-lw-us.apache.org (unknown [207.244.88.139]) by mailrelay1-us-west.apache.org (ASF Mail Server at mailrelay1-us-west.apache.org) with ESMTP id 818E5E2C62 for ; Tue, 21 May 2019 06:20:00 +0000 (UTC) Received: from jira-lw-us.apache.org (localhost [127.0.0.1]) by jira-lw-us.apache.org (ASF Mail Server at jira-lw-us.apache.org) with ESMTP id 3BBD025815 for ; Tue, 21 May 2019 06:20:00 +0000 (UTC) Date: Tue, 21 May 2019 06:20:00 +0000 (UTC) From: "Yiqun Lin (JIRA)" To: hdfs-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Updated] (HDFS-14503) ThrottledAsyncChecker throws NPE during block pool initialization MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/HDFS-14503?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Yiqun Lin updated HDFS-14503: ----------------------------- Description: ThrottledAsyncChecker throws NPE during block pool initialization. The error leads the block pool registration failure. The exception {noformat} 2019-05-20 01:02:36,003 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Unexpected exception in block pool Block pool (Datanode Uuid xxxxx) service to xx.xx.xx.xx/xx.xx.xx.xx java.lang.NullPointerException at org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker$LastCheckResult.access$000(ThrottledAsyncChecker.java:211) at org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker.schedule(ThrottledAsyncChecker.java:129) at org.apache.hadoop.hdfs.server.datanode.checker.DatasetVolumeChecker.checkAllVolumes(DatasetVolumeChecker.java:209) at org.apache.hadoop.hdfs.server.datanode.DataNode.checkDiskError(DataNode.java:3387) at org.apache.hadoop.hdfs.server.datanode.DataNode.initBlockPool(DataNode.java:1508) at org.apache.hadoop.hdfs.server.datanode.BPOfferService.verifyAndSetNamespaceInfo(BPOfferService.java:319) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndHandshake(BPServiceActor.java:272) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:768) at java.lang.Thread.run(Thread.java:745) {noformat} Looks like this error due to {{WeakHashMap}} type map {{completedChecks}} has removed the target entry while we still get that entry. Although we have done a check before we get it, there is still a chance the entry is got as null. We met a corner case for this: A federation mode, two block pools in DN, {{ThrottledAsyncChecker}} schedules two same health checks for same volume. {noformat} 2019-05-20 01:02:36,000 INFO org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker: Scheduling a check for /hadoop/2/hdfs/data/current 2019-05-20 01:02:36,000 INFO org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker: Scheduling a check for /hadoop/2/hdfs/data/current {noformat} {{completedChecks}} cleans up the entry for one successful check after called {{completedChecks#get}}. However, after this, another check we get the null. was: ThrottledAsyncChecker throws NPE during block pool initialization. The error leads the block pool registration failure. The exception {noformat} 2019-05-20 01:02:36,003 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Unexpected exception in block pool Block pool (Datanode Uuid xxxxx) service to xx.xx.xx.xx/xx.xx.xx.xx java.lang.NullPointerException at org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker$LastCheckResult.access$000(ThrottledAsyncChecker.java:211) at org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker.schedule(ThrottledAsyncChecker.java:129) at org.apache.hadoop.hdfs.server.datanode.checker.DatasetVolumeChecker.checkAllVolumes(DatasetVolumeChecker.java:209) at org.apache.hadoop.hdfs.server.datanode.DataNode.checkDiskError(DataNode.java:3387) at org.apache.hadoop.hdfs.server.datanode.DataNode.initBlockPool(DataNode.java:1508) at org.apache.hadoop.hdfs.server.datanode.BPOfferService.verifyAndSetNamespaceInfo(BPOfferService.java:319) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndHandshake(BPServiceActor.java:272) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:768) at java.lang.Thread.run(Thread.java:745) {noformat} Looks like this error due to {{WeakHashMap}} type map {{completedChecks}} has removed the target entry while we still get that entry. Although we have done a check before we get it, there is still a chance the entry is got as null. We met a corner case for this: A federation mode, two block pools in DN, {{ThrottledAsyncChecker}} schedules two same health checks for same volume. {noformat} 2019-05-20 01:02:36,000 INFO org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker: Scheduling a check for /hadoop/2/hdfs/data/current 2019-05-20 01:02:36,000 INFO org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker: Scheduling a check for /hadoop/2/hdfs/data/current {noformat} > ThrottledAsyncChecker throws NPE during block pool initialization > ------------------------------------------------------------------ > > Key: HDFS-14503 > URL: https://issues.apache.org/jira/browse/HDFS-14503 > Project: Hadoop HDFS > Issue Type: Improvement > Affects Versions: 3.3.0 > Reporter: Yiqun Lin > Priority: Major > > ThrottledAsyncChecker throws NPE during block pool initialization. The error leads the block pool registration failure. > The exception > {noformat} > 2019-05-20 01:02:36,003 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Unexpected exception in block pool Block pool (Datanode Uuid xxxxx) service to xx.xx.xx.xx/xx.xx.xx.xx > java.lang.NullPointerException > at org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker$LastCheckResult.access$000(ThrottledAsyncChecker.java:211) > at org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker.schedule(ThrottledAsyncChecker.java:129) > at org.apache.hadoop.hdfs.server.datanode.checker.DatasetVolumeChecker.checkAllVolumes(DatasetVolumeChecker.java:209) > at org.apache.hadoop.hdfs.server.datanode.DataNode.checkDiskError(DataNode.java:3387) > at org.apache.hadoop.hdfs.server.datanode.DataNode.initBlockPool(DataNode.java:1508) > at org.apache.hadoop.hdfs.server.datanode.BPOfferService.verifyAndSetNamespaceInfo(BPOfferService.java:319) > at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndHandshake(BPServiceActor.java:272) > at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:768) > at java.lang.Thread.run(Thread.java:745) > {noformat} > Looks like this error due to {{WeakHashMap}} type map {{completedChecks}} has removed the target entry while we still get that entry. Although we have done a check before we get it, there is still a chance the entry is got as null. > We met a corner case for this: A federation mode, two block pools in DN, {{ThrottledAsyncChecker}} schedules two same health checks for same volume. > {noformat} > 2019-05-20 01:02:36,000 INFO org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker: Scheduling a check for /hadoop/2/hdfs/data/current > 2019-05-20 01:02:36,000 INFO org.apache.hadoop.hdfs.server.datanode.checker.ThrottledAsyncChecker: Scheduling a check for /hadoop/2/hdfs/data/current > {noformat} > {{completedChecks}} cleans up the entry for one successful check after called {{completedChecks#get}}. However, after this, another check we get the null. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscribe@hadoop.apache.org For additional commands, e-mail: hdfs-issues-help@hadoop.apache.org