泥瓦匠的专栏

Ubuntu下测试ssh时使用ssh localhost 命令，出现错误提示connect to host localhost port 22:Connection refused 造成这个错误的原因可能是ssh-server未安装或者未启动。ubuntu 11.10 默认安装openssh-client，但是木有安装server 运行 ps -e | grep s

1.下载hadoop包：wget http://www.fightrice.com/mirrors/apache/hadoop/common/hadoop-1.2.0/hadoop-1.2.0.tar.gz

总是报出异常如下所示：13/07/24 09:14:24 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepT