一、pexpect简介
pexpect 是一个用来启动子程序并对其进行自动控制的 python 模块，它可以用来和像 ssh、ftp、passwd、telnet 等命令行程序进行自动交互。本文介绍 pexpect 的主要用法和在实际应用中的注意点。 python 语言的爱好者，系统管理人员，部署及测试人员都能使用 pexpect 在自己的工作中实现与命令行交互的自动化。
具体可以参考http://www.noah.org/wiki/pexpect#download_and_installation
下载地址 http://pexpect.sourceforge.net/pexpect-2.3.tar.gz
今天介绍的内容就是利用pexpect来实现的远程多服务器的管理。
二、python脚本
以下是python的源代码。程序的大概过程是使用pexpect的ssh命令循环登陆到远程服务器上，将服务和进程的运行情况纪录到临时文件中，然后再从文件中获取服务和进程的运行情况，如果服务或进程异常停止，程序则将其重新启动，所有服务器的运行状况都将纪录在日志文件中。
代码
# coding=utf-8
#!/usr/bin/env python
import pexpect
import getpass, os
import string
import time
from datetime import datetime, date
ssh_newkey = ‘are you sure you want to continue connecting (yes/no)?’
hosts = []
hosts.append(‘xx.xx.xx.xx’)
user = ‘user’
password = ‘pwd’
logfile = ‘/tmp/pexpect-2.3/monitor.log’
def restartservice(host, user, password, service):
child = pexpect.spawn(‘ssh %s@%s’ %(user, host))
i = child.expect([pexpect.timeout, ssh_newkey, ‘password: ‘])
if i == 0: # timeout
return none
if i == 1:
child.sendline(‘yes’)
child.sendline(password)
child.sendline(‘sudo service %s restart’ %service)
j = child.expect([‘password: ‘, ‘$’, ‘#’])
if j == 0:
child.sendline(password)
if j == 1:
child.sendline(password)
time.sleep(30)
child.sendline(‘exit’)
fout = file(logfile, ‘a’)
child.logfile_read = fout
return child
# restart one process
def restartprocess(host, user, password):
child = pexpect.spawn(‘ssh %s@%s’ %(user, host))
i = child.expect([pexpect.timeout, ssh_newkey, ‘password: ‘])
if i == 0: # timeout
return none
if i == 1:
child.sendline(‘yes’)
child.sendline(password)
child.sendline(‘sudo su’)
j = child.expect([‘password: ‘, ‘$’, ‘#’])
if j == 0:
child.sendline(password)
if j == 1:
child.sendline(password)
child.sendline(‘cd /processlocation/bin’)
child.sendline(‘./processname.sh &’)
time.sleep(20)
child.sendline(‘exit’)
child.sendline(‘exit’)
fout = file(logfile, ‘a’)
child.logfile_read = fout
return child
# log process’ status to file tmpproc.txt
def logprocessinfo(host, user, password, process):
child = pexpect.spawn(‘ssh %s@%s’ %(user, host))
i = child.expect([pexpect.timeout, ssh_newkey, ‘password: ‘])
if i == 0: # timeout
return none
if i == 1:
child.sendline(‘yes’)
child.sendline(password)
child.sendline(‘ps -ef|grep %s’ %process)
child.sendline(‘exit’)
fout = file(‘tmpproc.txt’, ‘w’)
child.logfile_read = fout
return child
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