hadoop-mapreduce-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jeff Stuckman <stuck...@umd.edu>
Subject RE: Site-specific dfs.client.local.interfaces setting not respected for Yarn MR container
Date Sun, 15 Dec 2013 21:01:42 GMT
Thanks for the response. I have the preferIPv4Stack option in hadoop-env.sh; however; this
was not preventing the mapreduce container from enumerating the IPv6 address of the interface.

Jeff

From: Chris Mawata [mailto:chris.mawata@gmail.com]
Sent: Sunday, December 15, 2013 3:58 PM
To: user@hadoop.apache.org
Subject: Re: Site-specific dfs.client.local.interfaces setting not respected for Yarn MR container

You might have better luck with an alternative approach to avoid having IPV6 which is to add
to your hadoop-env.sh

HADOOP_OPTS="$HADOOP_OPTS -Djava.net.preferIPv4Stack=true



Chris




On 12/14/2013 11:38 PM, Jeff Stuckman wrote:

Hello,



I have set up a two-node Hadoop cluster on Ubuntu 12.04 running streaming jobs with Hadoop
2.2.0. I am having problems with running tasks on a NM which is on a different host than the
RM, and I believe that this is happening because the NM host's dfs.client.local.interfaces
property is not having any effect.



I have two hosts set up as follows:

Host A (1.2.3.4):

NameNode

DataNode

ResourceManager

Job History Server



Host B (5.6.7.8):

DataNode

NodeManager



On each host, hdfs-site.xml was edited to change dfs.client.local.interfaces from an interface
name ("eth0") to the IPv4 address representing that host's interface ("1.2.3.4" or "5.6.7.8").
This is to prevent the HDFS client from randomly binding to the IPv6 side of the interface
(it randomly swaps between the IP4 and IP6 addresses, due to the random bind IP selection
in the DFS client) which was causing other problems.



However, I am observing that the Yarn container on the NM appears to inherit the property
from the copy of hdfs-site.xml on the RM, rather than reading it from the local configuration
file. In other words, setting the dfs.client.local.interfaces property in Host A's configuration
file causes the Yarn containers on Host B to use same value of the property. This causes the
map task to fail, as the container cannot establish a TCP connection to the HDFS. However,
on Host B, other commands that access the HDFS (such as "hadoop fs") do work, as they respect
the local value of the property.



To illustrate with an example, I start a streaming job from the command line on Host A:



hadoop jar $HADOOP_HOME/share/hadoop/tools/lib/hadoop-streaming-2.2.0.jar -input hdfs://hosta/linesin/
-output hdfs://hosta/linesout -mapper /home/hadoop/toRecords.pl -reducer /bin/cat



The NodeManager on Host B notes that there was an error starting the container:



13/12/14 19:38:45 WARN nodemanager.DefaultContainerExecutor: Exception from container-launch
with container ID: container_1387067177654_0002_01_000001 and exit code: 1

org.apache.hadoop.util.Shell$ExitCodeException:

        at org.apache.hadoop.util.Shell.runCommand(Shell.java:464)

        at org.apache.hadoop.util.Shell.run(Shell.java:379)

        at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:589)

        at org.apache.hadoop.yarn.server.nodemanager.DefaultContainerExecutor.launchContainer(DefaultContainerExecutor.java:195)

        at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:283)

        at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:79)

        at java.util.concurrent.FutureTask.run(Unknown Source)

        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

        at java.lang.Thread.run(Unknown Source)



On Host B, I open userlogs/application_1387067177654_0002/container_1387067177654_0002_01_000001/syslog
and find the following messages (note the DEBUG-level messages which I manually enabled for
the DFS client):



2013-12-14 19:38:32,439 DEBUG [main] org.apache.hadoop.hdfs.DFSClient: Using local interfaces
[1.2.3.4] with addresses [/1.2.3.4:0]

<cut>

2013-12-14 19:38:33,085 DEBUG [main] org.apache.hadoop.hdfs.DFSClient: newInfo = LocatedBlocks{

  fileLength=537

  underConstruction=false

  blocks=[LocatedBlock{BP-1911846690-1.2.3.4-1386999495143:blk_1073742317_1493; getBlockSize()=537;
corrupt=false; offset=0; locs=[5.6.7.8:50010, 1.2.3.4:50010]}]

  lastLocatedBlock=LocatedBlock{BP-1911846690-1.2.3.4-1386999495143:blk_1073742317_1493; getBlockSize()=537;
corrupt=false; offset=0; locs=[5.6.7.8:50010, 1.2.3.4:50010]}

  isLastBlockComplete=true}

2013-12-14 19:38:33,088 DEBUG [main] org.apache.hadoop.hdfs.DFSClient: Connecting to datanode
5.6.7.8:50010

2013-12-14 19:38:33,090 DEBUG [main] org.apache.hadoop.hdfs.DFSClient: Using local interface
/1.2.3.4:0

2013-12-14 19:38:33,095 WARN [main] org.apache.hadoop.hdfs.DFSClient: Failed to connect to
/5.6.7.8:50010 for block, add to deadNodes and continue. java.net.BindException: Cannot assign
requested address



Note the failure to bind to 1.2.3.4, as the IP for Node B's local interface is actually 5.6.7.8.



Note that when running other HDFS commands on Host B, Host B's setting for dfs.client.local.interfaces
is respected. On host B:



hadoop@nodeb:~$ hadoop fs -ls hdfs://hosta/

13/12/14 19:45:10 DEBUG hdfs.DFSClient: Using local interfaces [5.6.7.8] with addresses [/5.6.7.8:0]

Found 3 items

drwxr-xr-x   - hadoop supergroup          0 2013-12-14 00:40 hdfs://hosta/linesin

drwxr-xr-x   - hadoop supergroup          0 2013-12-14 02:01 hdfs://hosta/system

drwx------   - hadoop supergroup          0 2013-12-14 10:31 hdfs://hosta/tmp



If I change dfs.client.local.interfaces on Host A to eth0 (without touching the setting on
Host B), the syslog mentioned above instead shows the following:



2013-12-14 22:32:19,686 DEBUG [main] org.apache.hadoop.hdfs.DFSClient: Using local interfaces
[eth0] with addresses [/<some IP6 address>:0,/5.6.7.8:0]



The job then successfully completes sometimes, but both Host A and Host B will then randomly
alternate between the IP4 and IP6 side of their eth0 interfaces, which causes other issues.
In other words, changing the dfs.client.local.interfaces setting on Host A to a named adapter
caused the Yarn container on Host B to bind to an identically named adapter.

Any ideas on how I can reconfigure the cluster so every container will try to bind to its
own interface? I successfully worked around this issue by doing a custom build of HDFS which
hardcodes my IP address in the DFSClient, but I am looking for a better long-term solution.



Thanks,

Jeff



Mime
View raw message