hadoop conf

Examples

Displaying the configured value of a specific parameter

[user@hostname ~]$ hadoop conf | grep mapreduce.map.memory.mb
<property><name>mapreduce.map.memory.mb</name><value>1024</value><source>mapred-site.xml</source></property>

The above command returns 1024 as the configured value of the mapreduce.map.memory.mb parameter.

Dumping a node's configuration to a text file

[user@hostname ~]$ hadoop conf | grep ... >nodeconfiguration.txt  

The above command creates a text file named nodeconfiguration.txt that contains the node's configuration information.

The following information displays when you use the tail utility to examine the last few lines of the file:

[user@hostname ~]$ tail nodeconfiguration.txt
<property><name>yarn.resourcemanager.resource-tracker.client.thread-count</name><value>50</value><source>yarn-default.xml</source></property>
<property><name>yarn.timeline-service.leveldb-timeline-store.ttl-interval-ms</name><value>300000</value><source>yarn-default.xml</source></property>
<property><name>mapreduce.tasktracker.dns.nameserver</name><value>default</value><source>mapred-default.xml</source></property>
<property><name>yarn.resourcemanager.system</name><value>/var/mapr/cluster/yarn/rm/system</value></property>
<property><name>ipc.client.fallback-to-simple-auth-allowed</name><value>false</value><source>core-default.xml</source></property>
<property><name>mapreduce.map.output.compress</name><value>false</value><source>mapred-default.xml</source></property>
<property><name>fs.webhdfs.impl</name><value>org.apache.hadoop.hdfs.web.WebHdfsFileSystem</value></property>
<property><name>yarn.nodemanager.delete.debug-delay-sec</name><value>0</value><source>yarn-default.xml</source></property>
<property><name>hadoop.ssl.require.client.cert</name><value>false</value><source>core-default.xml</source></property>
</configuration>