hadoop/hadoop-hdfs-project/hadoop-hdfs/src/main/bin/start-dfs.sh

#!/usr/bin/env bash

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# this work for additional information regarding copyright ownership.
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#
#     http://www.apache.org/licenses/LICENSE-2.0
#
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# Start hadoop dfs daemons.
# Optinally upgrade or rollback dfs state.
# Run this on master node.

usage="Usage: start-dfs.sh [-upgrade|-rollback]"

bin=`dirname "${BASH_SOURCE-$0}"`
bin=`cd "$bin"; pwd`

DEFAULT_LIBEXEC_DIR="$bin"/../libexec
HADOOP_LIBEXEC_DIR=${HADOOP_LIBEXEC_DIR:-$DEFAULT_LIBEXEC_DIR}
. $HADOOP_LIBEXEC_DIR/hdfs-config.sh

# get arguments
if [ $# -ge 1 ]; then
	nameStartOpt="$1"
	shift
	case "$nameStartOpt" in
	  (-upgrade)
	  	;;
	  (-rollback) 
	  	dataStartOpt="$nameStartOpt"
	  	;;
	  (*)
		  echo $usage
		  exit 1
	    ;;
	esac
fi

#---------------------------------------------------------
# namenodes

NAMENODES=$($HADOOP_PREFIX/bin/hdfs getconf -namenodes)

echo "Starting namenodes on [$NAMENODES]"

"$HADOOP_PREFIX/sbin/hadoop-daemons.sh" \
  --config "$HADOOP_CONF_DIR" \
  --hostnames "$NAMENODES" \
  --script "$bin/hdfs" start namenode $nameStartOpt

#---------------------------------------------------------
# datanodes (using default slaves file)

if [ -n "$HADOOP_SECURE_DN_USER" ]; then
  echo \
    "Attempting to start secure cluster, skipping datanodes. " \
    "Run start-secure-dns.sh as root to complete startup."
else
  "$HADOOP_PREFIX/sbin/hadoop-daemons.sh" \
    --config "$HADOOP_CONF_DIR" \
    --script "$bin/hdfs" start datanode $dataStartOpt
fi

#---------------------------------------------------------
# secondary namenodes (if any)

SECONDARY_NAMENODES=$($HADOOP_PREFIX/bin/hdfs getconf -secondarynamenodes 2>&-)

echo "Starting secondary namenodes [$SECONDARY_NAMENODES]"

"$HADOOP_PREFIX/sbin/hadoop-daemons.sh" \
    --config "$HADOOP_CONF_DIR" \
    --hostnames "$SECONDARY_NAMENODES" \
    --script "$bin/hdfs" start secondarynamenode

# eof