解决CentOS下yum不能使用的错误(thread.error: can't start new thread)

在某台OpenVZ虚拟化的VPS上安装pptpd服务，结果遭遇yum无法使用的问题。执行yum后的错误代码如下：

• Loaded plugins: fastestmirror
• Setting up Remove Process
• No Match for argument: pptpd
• Determining fastest mirrors
• Traceback (most recent call last):
•   File "/usr/bin/yum", line 29, in ?
•     yummain.user_main(sys.argv[1:], exit_code=True)
•   File "/usr/share/yum-cli/yummain.py", line 309, in user_main
•     errcode = main(args)
•   File "/usr/share/yum-cli/yummain.py", line 178, in main
•     result, resultmsgs = base.doCommands()
•   File "/usr/share/yum-cli/cli.py", line 349, in doCommands
•     return self.yum_cli_commands[self.basecmd].doCommand(self, self.basecmd, self.extcmds)
•   File "/usr/share/yum-cli/yumcommands.py", line 366, in doCommand
•     return base.erasePkgs(extcmds)
•   File "/usr/share/yum-cli/cli.py", line 638, in erasePkgs
•     self._checkMaybeYouMeant(arg, always_output=False)
•   File "/usr/share/yum-cli/cli.py", line 533, in _checkMaybeYouMeant
•     matches = self.doPackageLists(patterns=[arg], ignore_case=False)
•   File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 1632, in doPackageLists
•     avail = self.pkgSack.returnNewestByNameArch(patterns=patterns,
•   File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 662, in <lambda>
•     pkgSack = property(fget=lambda self: self._getSacks(),
•   File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 502, in _getSacks
•     self.repos.populateSack(which=repos)
•   File "/usr/lib/python2.4/site-packages/yum/repos.py", line 232, in populateSack
•     self.doSetup()
•   File "/usr/lib/python2.4/site-packages/yum/repos.py", line 79, in doSetup
•     self.ayum.plugins.run('postreposetup')
•   File "/usr/lib/python2.4/site-packages/yum/plugins.py", line 179, in run
•     func(conduitcls(self, self.base, conf, **kwargs))
•   File "/usr/lib/yum-plugins/fastestmirror.py", line 181, in postreposetup_hook
•     all_urls = FastestMirror(all_urls).get_mirrorlist()
•   File "/usr/lib/yum-plugins/fastestmirror.py", line 333, in get_mirrorlist
•     self._poll_mirrors()
•   File "/usr/lib/yum-plugins/fastestmirror.py", line 376, in _poll_mirrors
•     pollThread.start()
•   File "/usr/lib/python2.4/threading.py", line 416, in start
•     _start_new_thread(self.__bootstrap, ())
• thread.error: can't start new thread

从下面这个博客中找到了解决方案：

http://www.tuccuay.com/2012/01/%E8%A7%A3%E5%86%B3thread-error-cant-start-new-thread%E9%94%99%E8%AF%AF/

在一些廉价VPS上运行Yum时可能会出 现:”thread.error: can’t start new thread”的错误， 原因就是因为内存太小了，以至于导致在寻找最快镜像的时候内存不足。

发生的原因在于fastestmirror，而禁用fastestmirror就可以解决这个问题，具体的解决办法是将fastestmirror.conf中的enabled=1改成enabled=0。

在登录SSH之后，编辑/etc/yum/pluginconf.d/fastestmirror.conf文件，把enabled从其中的把enabled=1改为enabled=0即可。

执行如下命令一键修改：

sed -i 's/enabled=1/enabled=0/g' /etc/yum/pluginconf.d/fastestmirror.conf