Hadoop 2.5.1 job stuck at map 0% and reduce 0% - hadoop

Question

I am trying to run a word count example. My current testing setup is:
NameNode and ResourceManager on one machine (10.38.41.134).
DataNode and NodeManager on another (10.38.41.135).
They can ssh between them without passwords.
When reading the logs, I don't get any warnings, except a security warning (I didn't set it up for testing) and a containermanager.AuxServices 'mapreduce_shuffle' warning. Upon submitting the example job, nodes react to it and output logs, which suggests that they can communicate well. NodeManager outputs memory usage, but the job doesn't budge.
Where should I even start looking for problems? Everything else I could find is either old or non-relevant. I followed the official cluster setup tutorial for version 2.5.1 which left way too many questions unanswered.
My conf files are following:
core-site.xml
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://10.38.41.134:9000</value>
</property>
</configuration>
hdfs-site.xml
<configuration>
<property>
<name>dfs.namenode.rpc-bind-host</name>
<value>0.0.0.0</value>
</property>
<property>
<name>dfs.namenode.servicerpc-bind-host</name>
<value>0.0.0.0</value>
</property>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
<property>
<name>dfs.client.block.write.replace-datanode-on-failure.enable</name>
<value>NEVER</value>
<description>
</description>
</property>
<property>
<name>dfs.namenode.datanode.registration.ip-hostname-check</name>
<value>false</value>
</property>
</configuration>
mapred-site.xml
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
<description>The runtime framework for executing MapReduce jobs.
Can be one of local, classic or yarn.
</description>
</property>
</configuration>
yarn-site.xml
<configuration>
<property>
<name>yarn.nodemanager.delete.debug-delay-sec</name>
<value>300</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
<property>
<name>yarn.nodemanager.aux-services.mapreduce.shuffle.class</name>
<value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>
<property>
<name>mapreduce.jobtracker.address</name>
<value>10.38.41.134:50030</value>
</property>
</configuration>
Everything else is default.

Answer 1

I suggest you first try to get it working with a single server cluster so it's easier to debug.
When that is working, continue with two nodes.
As already suggested, memory might be an issue. Without tweaking the settings, it seems some 2GB is the minimum and I'd recommend at least 4GB per server. Also remember to check also the job's logs (under logs/userlogs, especially syslog).
P.S. I share your frustration about old / non-relevant documentation.