findActiveNameNode.sh

#!/bin/bash
#set -x
#Author: Devopam, EXILANT Technologies Private Limited (www.exilant.com)
#Returns the active namenode FQDN via stdout
#Exit status non-zero for any un/handled errors. Suppress error messages if not desired
#Script replaces default http port to 8020 in the FQDN for direct consumption by Talend ETL job. Feel free to comment the next line if not desired
portName=":8020"

#check if script can execute hdfs commands
if [ ! -z "$HADOOP_HOME" ]; then
    set PATH=$PATH:$HADOOP_HOME/bin
fi

isBinaryAccessible=`which hdfs > /dev/null 2>&1`
status=$?

if [ $status -ne 0 ]; then
    echo "Could not locate hdfs executable. Please set HADOOP_HOME properly or add hdfs binary in your default PATH"
    exit 1
fi        

adminuser=`hdfs getconf -confKey dfs.cluster.administrators`
if [ $? -ne 0 ]; then   
    echo "User $USER doesn't have execute permission as hdfs admin OR cluster is not accessible from this host"
    exit 1
fi

#Uncomment the following block if you wish to get the commands executed only via administrators defined in hive-site.xml
#if [ `whoami` != $adminuser ]; then
#    echo "Please execute as user $adminuser"
#    exit 1
#fi

haClusterName=`hdfs getconf -confKey dfs.nameservices`

if [ $? -ne 0 -o -z "$haClusterName" ]; then
    echo "Unable to fetch HA ClusterName"
    exit 1
fi

nameNodeIdString=`hdfs getconf -confKey dfs.ha.namenodes.$haClusterName`


for nameNodeId in `echo $nameNodeIdString | tr "," " "`
do
    status=`hdfs haadmin -getServiceState $nameNodeId`
    if [ $status = "active" ]; then 
        nameNode=`hdfs getconf -confKey dfs.namenode.https-address.$haClusterName.$nameNodeId`
        if [ -z "$portName" ] ; then
            echo $nameNode
            exit 0;
        else
            echo `echo $nameNode|cut -d":" -f1`$portName
            exit 0;
        fi
    fi
done