Hello,
I am a HDFS newbie
I am using Hadoop version 2.4.1
And following instructions for cluster set-up from
http://hadoop.apache.org/docs/r2.4.1/hadoop-project-dist/hadoop-common/ClusterSetup.html
and for namenode federation from
http://hadoop.apache.org/docs/r2.3.0/hadoop-project-dist/hadoop-hdfs/Federation.html
I have set-up a HDFS cluster with one name-node and two data-nodes successfully
(with ease :))
I however am having challenges setting up a federated name-node.
All my machines are Suse Linux SLES 11
Here are the steps that I followed for adding a federated name node to my
working cluster
Step1: I set up a new SLES11 VM and installed HDFS on that
Step2 : Changed config in my hdfs-site.xml as follows and deployed on all
machines
<configuration>
<property>
<property>
<name>dfs.nameservices</name>
<value>ns1,ns2</value>
</property>
<name>dfs.namenode.name.dir</name>
<value>file:/home/hduser/mydata/hdfs/namenode</value>
<description>Space for name node to persist stuff</description>
</property>
<property>
<name>dfs.namenode.rpc-address.ns1</name>
<value>sles-hdfs1:9000</value>
</property>
<property>
<name>dfs.namenode.http-address.ns1</name>
<value>sles-hdfs1:50070</value>
</property>
<property>
<name>dfs.namenode.rpc-address.ns2</name>
<value>sles-hdfs4:9000</value>
</property>
<property>
<name>dfs.namenode.http-address.ns2</name>
<value>sles-hdfs2:50070</value>
</property>
<property>
<name>dfs.namenode.hosts</name>
<value>sles-hdfs2,sles-hdfs5</value>
<description>List of allowed data nodes</description>
</property>
</configuration>
Step3: I formatted my new name with same cluster id that I used for my first
(working) name node
hdfs namenode -format -clusterId CID-085f6f5f-784f-4b00-b3bf-937f2dd7808a
Step4: I start the new name node and it starts successfully
hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs start namenode
Hereafter - The instructions are somewhat unclear -
Next I am supposed to run the command
$ hdfs dfadmin -refreshNameNode <datanode_host_name>:<datanode_rpc_port>
Questions that I have are
- Do you see anything wrong in above configuration ?
- Where am I supposed to run this ( on name nodes, data nodes or on
every node) ?
- I suppose the default data node rpc port is "8020" - and I should be
able to set it by a property in hdfs-site.xml ( dfs.datanode.ipc.address ) -
is that correct ?
- Regarding SSH configuration - I have created a ssh cert only on my
primary node ( using ssh-keygen) and copied it on all other data and the new
name nodes using ssh-copy-id. Would it be necessary to create cert for the new
name node as well ?
Just FYI - server names of my nodes
sles-hdfs1- primary name node
sles-hdfs2-One Data node
sles-hdfs5- Another Data node
sles-hdfs4 -new federated name node
