搭建hadoop环境
因为想在windows平台下开发Hadoop，所以安装了一个cygwin。cygwin是一个可以在windows上模拟linux运行环境的软件，使用它的客户端可以方便的在windows上进行Linux平台的操作。下面总结一下中间遇到的问题和解决方法：
首先要下载一个cygwin的安装程序，下载安装程序，下载地址为： http://www.cygwin.com/setup.exe 选择必须安装的包,根据实践有如下包必须选择安 装，否则很可能cygwin安装失败！
Net Category下的OpenSSL，OpenSSH;
Base Category下的sed;
Editors Category下的vim,Emacs;
Devel Category下的subversion,binutils,gcc,gcc-mingw,gdb
安装完成之后，就要配置host并且安装sshd服务了，这里要强调一下sshd服务，很多网上的安装教程没有提到如何安装，其实就是在运行ssh-host-config命令之后安装。里面有这个选项，按照如下操作：
必须要以管理员身份运行cygwin，否则会安装失败，然后运行命令ssh-host-config。

$ ssh-host-config
*** Info: Generating /etc/ssh_host_key
unknown key type
*** Info: Generating /etc/ssh_host_rsa_key
unknown key type
*** Info: Generating /etc/ssh_host_dsa_key
unknown key type
*** Query: Overwrite existing /etc/ssh_config file? (yes/no) yes
*** Info: Creating default /etc/ssh_config file
*** Query: Overwrite existing /etc/sshd_config file? (yes/no) yes
*** Info: Creating default /etc/sshd_config file
*** Info: Privilege separation is set to yes by default since OpenSSH 3.3.
*** Info: However, this requires a non-privileged account called 'sshd'.
*** Info: For more info on privilege separation read /usr/share/doc/openss
ME.privsep.
*** Query: Should privilege separation be used? (yes/no) no
*** Info: Updating /etc/sshd_config file
mount: invalid option - 'text,posix=0,noacl'
grep: /ssh-host-config.7180/services: No such file or directory
grep: /ssh-host-config.7180/services: No such file or directory
/usr/bin/ssh-host-config: line 119: /ssh-host-config.7180/services: No suc
or directory
*** Warning: Adding ssh to D:umount: /ssh-host-config.7180: Invalid argume
*** Warning: The following functions require administrator privileges!
*** Query: Do you want to install sshd as a service?
*** Query: (Say "no" if it is already installed as a service) (yes/no) yes
*** Query: Enter the value of CYGWIN for the daemon: [] ntsec
*** Info: On Windows Server 2003, Windows Vista, and above, the
*** Info: SYSTEM account cannot setuid to other users -- a capability
*** Info: sshd requires. You need to have or to create a privileged
*** Info: account. This script will help you do so.
*** Info: You appear to be running Windows 2003 Server or later. On 2003
*** Info: and later systems, it's not possible to use the LocalSystem
*** Info: account for services that can change the user id without an
*** Info: explicit password (such as passwordless logins [e.g. public key
*** Info: authentication] via sshd).
*** Info: If you want to enable that functionality, it's required to creat
*** Info: a new account with special privileges (unless a similar account
*** Info: already exists). This account is then used to run these special
*** Info: servers.
*** Info: Note that creating a new user requires that the current account
*** Info: have Administrator privileges itself.
*** Info: No privileged account could be found.
*** Info: This script plans to use 'cyg_server'.
*** Info: 'cyg_server' will only be used by registered services.
*** Query: Do you want to use a different name? (yes/no) no
*** Query: Create new privileged user account 'cyg_server'? (yes/no) yes
*** Info: Please enter a password for new user cyg_server. Please be sure
*** Info: that this password matches the password rules given on your syst
*** Info: Entering no password will exit the configuration.
*** Query: Please enter the password:
*** Query: Reenter:
*** Info: User 'cyg_server' has been created with password 'root'.
*** Info: If you change the password, please remember also to change the
*** Info: password for the installed services which use (or will soon use)
*** Info: the 'cyg_server' account.
*** Info: Also keep in mind that the user 'cyg_server' needs read permissi
*** Info: on all users' relevant files for the services running as 'cyg_se
*** Info: In particular, for the sshd server all users' .ssh/authorized_ke
*** Info: files must have appropriate permissions to al