Linux，全称GNU/Linux，是一种免费使用和自由传播的类UNIX操作系统，其内核由林纳斯·本纳第克特·托瓦兹于1991年10月5日首次发布，它主要受到Minix和Unix思想的启发，是一个基于POSIX的多用户、多任务、支持多线程和多CPU的操作系统。
无线环境下,启动namenode时出现ssh错误
ssh: connect to host hadoop port 22: No route to host
Starting namenodes on [hadoop]
hadoop: ssh: connect to host hadoop port 22: No route to host
localhost: starting datanode, logging to /usr/hadoop/logs/hadoop-hadoop-datanode-Lenovo-V3000.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/hadoop/logs/hadoop-hadoop-secondarynamenode-Lenovo-V3000.out
hadoop@Lenovo-V3000:~$ ssh localhost
Welcome to Ubuntu 16.04.3 LTS (GNU/Linux 4.10.0-33-generic x86_64)
解决方法
查看 /etc/hosts 中配置的 IP hostname 是否改变,无线环境下,IP 会自动分配
通过ip a 查看相应的ip 与 /etc/hosts下的ip地址是否相同,不同要保持hosts文件与ip a 中的无线IP 保持一致。
ip a
1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp2s0: mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
link/ether 50:7b:9d:0a:87:32 brd ff:ff:ff:ff:ff:ff
3: wlp3s0: mtu 1500 qdisc mq state UP group default qlen 1000
link/ether e4:f8:9c:da:b0:a1 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.210/24 brd 192.168.1.255 scope global dynamic wlp3s0
valid_lft 83110sec preferred_lft 83110sec
inet6 fe80::f69c:afa:2321:fd82/64 scope lin
cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 Lenovo-V3000
# 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
#192.168.1.240 hadoop
192.168.1.210 hadoop
发现之前的是240,已经不存在,需要修改成210