配置好hadoop-2.7.7后，执行启动 ./start-all.sh，报错：
Incorrect configuration: namenode address dfs.namenode.servicerpc
-address or dfs.namenode.rpc-address is not configured.
[root@master hadoop]#Incorrect configuration: namenode address dfs.namenode.servicerpc -address or dfs.namenode.rpc-address is not configured. Starting namenodes on [] Error: Cannot find configuration directory: /opt/hahadoop-2.7.7/etc/hadoop Error: Cannot find configuration directory: /opt/hahadoop-2.7.7/etc/hadoop Starting secondary namenodes [0.0.0.0] Error: Cannot find configuration director
这是因为使用了hadoop-env.sh默认的关于hadoop配置文件所在目录的配置，这里需要根据你自己的安装路径重新设置。
进入/etc/hadoop文件夹下
修改hadoop-env.sh文件
将原本的相对路径注释掉，换成绝对路径
export HADOOP_CONF_DIR=/opt/hadoop-2.7.7/etc/hadoop
最后保存文件分发给其他节点。
