I. overview

It is a reliable, scalable and distributed open source software.
It is a framework that allows large data and distributed processing across clusters of computers, using a simple programming model (mapreduce)
It can be extended from a single server to thousands of hosts, and each node provides computing and storage functions.
Hardware-independent HA implementation at application level

Volume is large
velocity
variaty
Low value density

hadoop common class library, supporting other modules
HDFS, hadoop distributed file system, hadoop distributed file system
Hadoop yarn Job Scheduling and Resource Management Framework
Haoop MapReduce is a parallel processing technology for large data sets based on yarn system.

II. Installation and Deployment

2.1 Host Planning

Host name	IP address	Installation node application
hadoop-1	172.20.2.203	namenode/datanode/nodemanager
hadoop-2	172.20.2.204	secondarynode/datanode/nodemanager
hadoop-3	172.20.2.205	resourcemanager/datanode/nodemanager

2.2 deployment

2.2.1 Basic Environment Configuration

yum install java-1.8.0-openjdk.x86_64 java-1.8.0-openjdk-devel -y
cat >/etc/profile.d/java.sh<<EOF
export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.161-3.b14.el6_9.x86_64
export CLASSPATH=.:\$JAVA_HOME/jre/lib/rt.jar:\$JAVA_HOME/lib/dt.jar:\$JAVA_HOME/lib/tools.jar 
export PATH=\$PATH:\$JAVA_HOME/bin
EOF
source /etc/profile.d/java.sh

hostname hadoop-1
cat >>/etc/hosts<<EOF
172.20.2.203    hadoop-1
172.20.2.204    hadoop-2
172.20.2.205    hadoop-3
EOF

useradd hadoop
echo "hadoopwd" |passwd hadoop --stdin
mkdir -pv /data/hadoop/hdfs/{nn,snn,dn}
chown -R hadoop:hadoop /data/hadoop/hdfs/
mkdir -p /var/log/hadoop/yarn
mkdir -p /dbapps/hadoop/logs
chmod g+w /dbapps/hadoop/logs/
chown -R hadoop.hadoop /dbapps/hadoop/

cat>/etc/profile.d/hadoop.sh<<EOF
export HADOOP_PREFIX=/usr/local/hadoop
export PATH=\$PATH:\$HADOOP_PREFIX/bin:\$HADOOP_PREFIX/sbin
export HADOOP_COMMON_HOME=\${HADOOP_PREFIX}
export HADOOP_HDFS_HOME=\${HADOOP_PREFIX}
export HADOOP_MAPRED_HOME=\${HADOOP_PREFIX}
export HADOOP_YARN_HOME=\${HADOOP_PREFIX}
EOF
source /etc/profile.d/hadoop.sh

mkdir /software 
cd /software 
wget -c http://www.apache.org/dyn/closer.cgi/hadoop/common/hadoop-2.7.5/hadoop-2.7.5.tar.gz
tar -zxf hadoop-2.6.5.tar.gz -C /usr/local
ln -sv /usr/local/hadoop-2.6.5/ /usr/local/hadoop
chown hadoop.hadoop /usr/local/hadoop-2.6.5/ -R

su - hadoop
ssh-keygen -t rsa
for num in `seq 1 3`;do ssh-copy-id -i /home/hadoop/.ssh/id_rsa.pub hadoop@hadoop-$num;done

2.3 Configure hadoop

2.3.1 Configuration of nodes

The hadoop-1 node runs namenode/datanode/nodemanager and modifies the Hadoop configuration file for hadoop-1

core-site.xml (defining namenode nodes)

cat>/usr/local/hadoop/etc/hadoop/core-site.xml <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://hadoop-1:8020</value>
<final>true</final>
</property>
</configuration>
EOF

hdfs-site.xml modifies replication to the number of data nodes (defining secondary nodes)

cat >/usr/local/hadoop/etc/hadoop/hdfs-site.xml <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>dfs.namenode.secondary.http-address</name>
<value>hadoop-2:50090</value>
</property>
<property>
<name>dfs.replication</name>
<value>2</value>
</property>
<property>
<name>dfs.namenode.name.dir</name>
<value>file:///data/hadoop/hdfs/nn</value>
</property>
<property>
<name>dfs.datanode.data.dir</name>
<value>file:///data/hadoop/hdfs/dn</value>
</property>
<property>
<name>fs.checkpoint.dir</name>
<value>file:///data/hadoop/hdfs/snn</value>
</property>
<property>
<name>fs.checkpoint.edits.dir</name>
<value>file:///data/hadoop/hdfs/snn</value>
</property>
</configuration>
EOF

Add mapred-site.xml

cat >/usr/local/hadoop/etc/hadoop/mapred-site.xml <<EOF
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
</configuration>
EOF

yarn-site.xml modifies the host name corresponding to values as master (defines the resourcemanager node)

cat >/usr/local/hadoop/etc/hadoop/yarn-site.xml<<EOF
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>yarn.resourcemanager.address</name>
<value>hadoop-3:8032</value>
</property>
<property>
<name>yarn.resourcemanager.scheduler.address</name>
<value>hadoop-3:8030</value>
</property>
<property>
<name>yarn.resourcemanager.resource-tracker.address</name>
<value>hadoop-3:8031</value>
</property>
<property>
<name>yarn.resourcemanager.admin.address</name>
<value>hadoop-3:8033</value>
</property>
<property>
<name>yarn.resourcemanager.webapp.address</name>
<value>hadoop-3:8088</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
<property>
<name>yarn.nodemanager.auxservices.mapreduce_shuffle.class</name>
<value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>
<property>
<name>yarn.resourcemanager.scheduler.class</name>
<value>org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler</value>
</property>
</configuration>
EOF

Slaves (Defining data nodes)

cat >/usr/local/hadoop/etc/hadoop/slaves<<EOF
hadoop-1
hadoop-2
hadoop-3
EOF

The same procedure operates on hadoop-2/3. It is recommended that the files of hadoop-1 be distributed directly to hadoop-2/3.

2.3.2 Format namenode

Perform formatting on the NameNode machine (hadoop-1):

hdfs namenode -format

2.3.3 Startup Services

Execute start-all.sh startup service in namenode hadoop-1
Start the resource manager service in hadoop-3``

hadoop-2 service view

hadoop-3 service view

2.3.4 Running Test Program

yarn jar /usr/local/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.5.jar pi 2 10

2.3.5 View web Interface

HDFS-NameNode

url:http://172.20.2.203:50070

YARN-ResourceManager

url:http://172.20.2.205:8088