HDFS experiment (4) Cluster operation
Cluster setup
Http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/ClusterSetup.html
user's manual
Http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-hdfs/HdfsUserGuide.html
Daemon
Environment Variable
NameNode
HDFS_NAMENODE_OPTS
DataNode
HDFS_DATANODE_OPTS
Secondary NameNode
HDFS_SECONDARYNAMENODE_OPTS
ResourceManager
YARN_RESOURCEMANAGER_OPTS
NodeManager
YARN_NODEMANAGER_OPTS
WebAppProxy
YARN_PROXYSERVER_OPTS
Map Reduce Job History Server
MAPRED_HISTORYSERVER_OPTS
To start a Hadoop cluster you will need to start both the HDFS and YARN cluster.
The first time you bring up HDFS, it must be formatted. Format a new distributed filesystem as hdfs:
[hdfs] $$HADOOP_HOME/bin/hdfs namenode-format
Start the HDFS NameNode with the following command on the designated node as hdfs:
[hdfs] $$HADOOP_HOME/bin/hdfs-- daemon start namenode
Start a HDFS DataNode with the following command on each designated node as hdfs:
[hdfs] $$HADOOP_HOME/bin/hdfs-- daemon start datanode
If etc/hadoop/workers and ssh trusted access is configured (see Single Node Setup), all of the HDFS processes can be started with a utility script. As hdfs:
[hdfs] $$HADOOP_HOME/sbin/start-dfs.sh
Start the YARN with the following command, run on the designated ResourceManager as yarn:
[yarn] $$HADOOP_HOME/bin/yarn-- daemon start resourcemanager
Run a script to start a NodeManager on each designated host as yarn:
[yarn] $$HADOOP_HOME/bin/yarn-- daemon start nodemanager
Start a standalone WebAppProxy server. Run on the WebAppProxy server as yarn. If multiple servers are used with load balancing it should be run on each of them:
[yarn] $$HADOOP_HOME/bin/yarn-- daemon start proxyserver
If etc/hadoop/workers and ssh trusted access is configured (see Single Node Setup), all of the YARN processes can be started with a utility script. As yarn:
[yarn] $$HADOOP_HOME/sbin/start-yarn.sh
Start the MapReduce JobHistory Server with the following command, run on the designated server as mapred:
[mapred] $$HADOOP_HOME/bin/mapred-- daemon start historyserver
Hadoop Shutdown
Stop the NameNode with the following command, run on the designated NameNode as hdfs:
[hdfs] $$HADOOP_HOME/bin/hdfs-- daemon stop namenode
Run a script to stop a DataNode as hdfs:
[hdfs] $$HADOOP_HOME/bin/hdfs-- daemon stop datanode
If etc/hadoop/workers and ssh trusted access is configured (see Single Node Setup), all of the HDFS processes may be stopped with a utility script. As hdfs:
[hdfs] $$HADOOP_HOME/sbin/stop-dfs.sh
Stop the ResourceManager with the following command, run on the designated ResourceManager as yarn:
[yarn] $$HADOOP_HOME/bin/yarn-- daemon stop resourcemanager
Run a script to stop a NodeManager on a worker as yarn:
[yarn] $$HADOOP_HOME/bin/yarn-- daemon stop nodemanager
If etc/hadoop/workers and ssh trusted access is configured (see Single Node Setup), all of the YARN processes can be stopped with a utility script. As yarn:
[yarn] $$HADOOP_HOME/sbin/stop-yarn.sh
Stop the WebAppProxy server. Run on the WebAppProxy server as yarn. If multiple servers are used with load balancing it should be run on each of them:
[yarn] $$HADOOP_HOME/bin/yarn stop proxyserver
Stop the MapReduce JobHistory Server with the following command, run on the designated server as mapred:
[mapred] $$HADOOP_HOME/bin/mapred-- daemon stop historyserver
Web Interfaces
Once the Hadoop cluster is up and running check the web-ui of the components as described below:
Daemon
Web Interface
Notes
NameNode
Http://nn_host:port/
Default HTTP port is 9870.
ResourceManager
Http://rm_host:port/
Default HTTP port is 8088.
MapReduce JobHistory Server
Http://jhs_host:port/
Default HTTP port is 19888.
