Ubuntu16.04 Hadoop2.6.0伪分布式安装与启动中遇到的问题

1.安装JDK1.8，下载安装包解压至 /usr/lib/jdk

vim /etc/profile

#配置路径

export JAVA_HOME= /usr/lib/jdk
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH

2.之前已经安装好SSH，现在设置免密码登录

ssh-keygen -t rsa

cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

测试设置是否成功

ssh localhost

3.下载Hadoop2.6.0，解压至/home/super/software/hadoop

设置环境变量

sudo gedit ~/.bashrc

添加

export JAVA_HOME=/usr/lib/jdk
export HADOOP_HOME=/home/super/software/hadoop
export PATH=$PATH:$HADOOP_HOME/bin
export PATH=$PATH:$HADOOP_HOME/sbin
export HADOOP_MAPRED_HOME=$HADOOP_HOME
export HADOOP_COMMON_HOME=$HADOOP_HOME
export HADOOP_HDFS_HOME=$HADOOP_HOME
export YARN_HOME=$HADOOP_HOME
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export HADOOP_OPTS="-Djava.library.path=$HADOOP_HOME/lib"
export JAVA_LIBRARY_PATH=$HADOOP_HOME/lib/native:$JAVA_LIBRARY_PATH

使环境生效

source ~/.bashrc

【ps:在后续出现start-all.sh/stop-all.sh未找到命令的情况，解决方案：①cd到sbin目录下执行命令②再次运行source ~/.bashrc】

4.修改hadoop/etc/hadoop下的配置设置文件

修改hadoop-env.sh

export JAVA_HOME= /usr/lib/jdk

修改core-site.xml

<property>
  <name>fs.default.name</name>
  <value>hdfs://localhost:9000</value>
</property>

修改yarn-site.xml

<property>
  <name>yarn.nodemanager.aux-services</name>
  <value>mapreduce_shuffle</value>
</property>
<property>
  <name>yarn.nodemanager.aux-services.mapreduce.shuffle.class</name>
  <value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>

先将mapred-site.xml.template复制成mapred-site.xml，修改mapred-site.xml

<property>
  <name>mapreduce.framework.name</name>
  <value>yarn</value>
</property>

修改hdfs-site.xml

<property>
  <name>dfs.replication</name>
  <value>3</value>
</property>
<property>
  <name>dfs.namenode.name.dir</name>
  <value>file:/home/super/software/hadoop/hadoop_data/hdfs/namenode</value>
</property>
<property>
  <name>dfs.datanode.data.dir</name>
  <value>file:/home/super/software/hadoop/hadoop_data/hdfs/datanode</value>
</property>

创建namenode和datanode数据存储目录

sudo mkdir -p /home/super/software/hadoop/hadoop_data/hdfs/namenode
sudo mkdir -p /home/super/software/hadoop/hadoop_data/hdfs/datanode

格式化namenode

hadoop namenode -format

启动hadoop

start-all.sh

输入jps查看结果

本来应该输出六个进程，结果只输出了四个，DataNode和NameNode未启动

ResourceManager

Jps

DataNode

SecondaryNameNode

NameNode

NodeManager

　　

查看/home/super/software/hadoop/logs下DataNode的启动日志，发现报错all directories in dfs.data.dir are invalid

目录权限问题导致节点无法启动

sudo chown super:super -R /home/super/software/hadoop

查看/home/super/software/hadoop/logs下NameNode的启动日志，发现报错NameNode is not formatted

因为之前格式化次数过多引起的clusterID变化。关闭Hadoop再进行一次格式化重新启动就行。

stop-all.sh
hadoop namenode -format

重新启动后问题得到解决！