Grokbase Groups HBase user June 2011
FAQ
All,

You may have seen my previous email regarding Master node crashing, but upon
further research we may have other issues.

I went out to the RegionServer (H3S3) and verified that the process was
running. There was no meaningful log output, and the last output was from
48 hours ago indicating a log roll.

*Previous State:*
Master died (H3M1)

*Corrective Actions:*
I restarted the master out on H3M1, and it started by trying to recover logs
out on H3S3. There were many entries like

2011-06-27 11:36:25,639 WARN org.apache.hadoop.hbase.util.FSUtils: Waited
1701352ms for lease recovery on
hdfs://H3M1:8020/hbase/.logs/H3S3,60020,1308946657608/H3S3%3A60020.1309015083129:org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException:
failed to create file
/hbase/.logs/H3S3,60020,1308946657608/H3S3%3A60020.1309015083129 for
DFSClient_hb_m_H3M1:60000_1309194478697 on client 10.x.x.x, because this
file is already being created by
DFSClient_hb_rs_H3S3,60020,1308946657608_1308946657819 on 10.5.241.203
at
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInternal(FSNamesystem.java:1196)
at
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.appendFile(FSNamesystem.java:1284)
at org.apache.hadoop.hdfs.server.namenode.NameNode.append(NameNode.java:596)
at sun.reflect.GeneratedMethodAccessor48.invoke(Unknown Source)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:557)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1416)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1412)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1115)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1410)


Then we decided to kill -9 the regionserver process out on H3S3, and
received the following in the master:

2011-06-27 11:36:26,006 INFO
org.apache.hadoop.hbase.zookeeper.RegionServerTracker: RegionServer
ephemeral node deleted, processing expiration [H3S3,60020,1308946657608]
2011-06-27 11:36:26,006 INFO
org.apache.hadoop.hbase.zookeeper.RegionServerTracker: No HServerInfo found
for H3S3,60020,1308946657608


Ultimately, the master came up and transitioned the regions to a different
regionserver.

Is there a situation where the regionserver may become unresponsive yet the
zookeeper client portion of the process can still check in and tickle
zookeeper so the master thinks it alive? I think this may be why, in my
previous post, the master tried to assign to H3S3 and died in the attempt.


Thanks!
-Matt

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  • Jean-Daniel Cryans at Jun 27, 2011 at 5:59 pm
    Did you jstack the region server before killing it? We could see what
    was still living, although logs might also give us a clue. As long as
    the client ZK thread is alive, the znode will stay up.

    About the last message:
    org.apache.hadoop.hbase.zookeeper.RegionServerTracker: No HServerInfo found
    for H3S3,60020,1308946657608
    That's usually given when you have a DNS issue, where the hostname and
    FQDN are mixed up. See http://hbase.apache.org/book/os.html#dns

    J-D
    On Mon, Jun 27, 2011 at 10:45 AM, Matt Davies wrote:
    All,

    You may have seen my previous email regarding Master node crashing, but upon
    further research we may have other issues.

    I went out to the RegionServer (H3S3) and verified that the process was
    running.  There was no meaningful log output, and the last output was from
    48 hours ago indicating a log roll.

    *Previous State:*
    Master died (H3M1)

    *Corrective Actions:*
    I restarted the master out on H3M1, and it started by trying to recover logs
    out on H3S3.  There were many entries like

    2011-06-27 11:36:25,639 WARN org.apache.hadoop.hbase.util.FSUtils: Waited
    1701352ms for lease recovery on
    hdfs://H3M1:8020/hbase/.logs/H3S3,60020,1308946657608/H3S3%3A60020.1309015083129:org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException:
    failed to create file
    /hbase/.logs/H3S3,60020,1308946657608/H3S3%3A60020.1309015083129 for
    DFSClient_hb_m_H3M1:60000_1309194478697 on client 10.x.x.x, because this
    file is already being created by
    DFSClient_hb_rs_H3S3,60020,1308946657608_1308946657819 on 10.5.241.203
    at
    org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInternal(FSNamesystem.java:1196)
    at
    org.apache.hadoop.hdfs.server.namenode.FSNamesystem.appendFile(FSNamesystem.java:1284)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.append(NameNode.java:596)
    at sun.reflect.GeneratedMethodAccessor48.invoke(Unknown Source)
    at
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:557)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1416)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1412)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at
    org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1115)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1410)


    Then we decided to kill -9 the regionserver process out on H3S3, and
    received the following in the master:

    2011-06-27 11:36:26,006 INFO
    org.apache.hadoop.hbase.zookeeper.RegionServerTracker: RegionServer
    ephemeral node deleted, processing expiration [H3S3,60020,1308946657608]
    2011-06-27 11:36:26,006 INFO
    org.apache.hadoop.hbase.zookeeper.RegionServerTracker: No HServerInfo found
    for H3S3,60020,1308946657608


    Ultimately, the master came up and transitioned the regions to a different
    regionserver.

    Is there a situation where the regionserver may become unresponsive yet the
    zookeeper client portion of the process can still check in and tickle
    zookeeper so the master thinks it alive?  I think this may be why, in my
    previous post, the master tried to assign to H3S3 and died in the attempt.


    Thanks!
    -Matt

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categorieshbase, hadoop
postedJun 27, '11 at 5:46p
activeJun 27, '11 at 5:59p
posts2
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websitehbase.apache.org

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Matt Davies: 1 post Jean-Daniel Cryans: 1 post

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