查了DataNode的日志，显示：
WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Problem connecting to server: master/192.168.152.129:9000
master和slaver之间都ping的通
新手不太懂。。然后去网上查了，初步确定应该是9000端口没有开。

在master端查询：
hadoop@master:~$ netstat -an | grep 9000
tcp 0 0 127.0.1.1:9000 0.0.0.0:* LISTEN

tcp 0 0 127.0.0.1:38830 127.0.1.1:9000 TIME_WAIT

但接下来不知道怎么做

这是/etc/hosts

127.0.0.1 localhost
127.0.1.1 master

192.168.152.129 master
192.168.152.131 slave1
192.168.152.132 slave2

The following lines are desirable for IPv6 capable hosts

::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

网上说是防火墙的问题，我也试过了。ufw status都是inactive