Linux系統yum安裝報錯Cannot find a valid baseurl for repo的解決方法

yum install error
[root@localhost cmake-3.2.2]# yum install gcc
Loaded plugins: fastestmirror, refresh-packagekit, security
Could not retrieve mirrorlist error was
14: PYCURL ERROR 6 - "Couldn't resolve host 'mirrorlist.centos.org'"
Error: Cannot retrieve repository metadata (repomd.xml) for repository: base. Please verify its path and try again
[root@localhost cmake-3.2.2]# yum install gcc-c++
Loaded plugins: fastestmirror, refresh-packagekit, security
Determining fastest mirrors
Could not retrieve mirrorlist error was
14: PYCURL ERROR 6 - "Couldn't resolve host 'mirrorlist.centos.org'"
Error: Cannot find a valid baseurl for repo: base

解決方法如下（修改dns配置）

vi /etc/resolv.conf
在此檔案最後加入：nameserver 114.114.114.114

再次安裝正常：
[root@localhost cmake-3.2.2]# yum install gcc
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
 * base: mirrors.tuna.tsinghua.edu.cn
 * extras: mirrors.btte.net
 * updates: mirrors.tuna.tsinghua.edu.cn
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package gcc.x86_64 0:4.4.7-17.el6 will be installed
--> Processing Dependency: libgomp = 4.4.7-17.el6 for package: gcc-4.4.7-17.el6.x86_64
--> Processing Dependency: cpp = 4.4.7-17.el6 for package: gcc-4.4.7-17.el6.x86_64
--> Processing Dependency: libgcc >= 4.4.7-17.el6 for package: gcc-4.4.7-17.el6.x86_64
--> Processing Dependency: cloog-ppl >= 0.15 for package: gcc-4.4.7-17.el6.x86_64
--> Running transaction check
---> Package cloog-ppl.x86_64 0:0.15.7-1.2.el6 will be installed
--> Processing Dependency: libppl_c.so.2()(64bit) for package: cloog-ppl-0.15.7-1.2.el6.x86_64
--> Processing Dependency: libppl.so.7()(64bit) for package: cloog-ppl-0.15.7-1.2.el6.x86_64
---> Package cpp.x86_64 0:4.4.7-17.el6 will be installed
--> Processing Dependency: libmpfr.so.1()(64bit) for package: cpp-4.4.7-17.el6.x86_64
---> Package libgcc.i686 0:4.4.7-4.el6 will be updated
---> Package libgcc.x86_64 0:4.4.7-4.el6 will be updated
---> Package libgcc.i686 0:4.4.7-17.el6 will be an update
---> Package libgcc.x86_64 0:4.4.7-17.el6 will be an update
---> Package libgomp.x86_64 0:4.4.7-4.el6 will be updated
---> Package libgomp.x86_64 0:4.4.7-17.el6 will be an update
--> Running transaction check
---> Package mpfr.x86_64 0:2.4.1-6.el6 will be installed
---> Package ppl.x86_64 0:0.10.2-11.el6 will be installed
--> Finished Dependency Resolution


Dependencies Resolved


==============================================================================================================================================
 Package                           Arch                           Version                                  Repository                    Size
==============================================================================================================================================
Installing:
 gcc                               x86_64                         4.4.7-17.el6                             base                          10 M
Installing for dependencies:
 cloog-ppl                         x86_64                         0.15.7-1.2.el6                           base                          93 k
 cpp                               x86_64                         4.4.7-17.el6                             base                         3.7 M
 mpfr                              x86_64                         2.4.1-6.el6                              base                         157 k
 ppl                               x86_64                         0.10.2-11.el6                            base                         1.3 M
Updating for dependencies:
 libgcc                            i686                           4.4.7-17.el6                             base                         114 k
 libgcc                            x86_64                         4.4.7-17.el6                             base                         103 k
 libgomp                           x86_64                         4.4.7-17.el6                             base                         134 k


Transaction Summary
==============================================================================================================================================
Install       5 Package(s)
Upgrade       3 Package(s)


Total download size: 16 M
Is this ok [y/N]: