1、重新格式化namenode
cd ~
rm -rf name
mkdir name
rm -rf hadoop-2.7.2/logs/
mkdir hadoop-2.7.2/logs/ hadoop-2.7.2/bin/hdfs namenode -format
2、检查hosts文件
vi /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
10.20.77.172 hadoop-master
10.20.77.173 hadoop-slave1
10.20.77.174 hadoop-slave2
10.20.77.175 hadoop-slave3
3、关闭防火墙
systemctl stop firewalld.service # 关闭firewall
systemctl disable firewalld.service # 禁止firewall开机启动