Background note:
There is a project that uses Node.js, so the running environment of node V6.4.0 needs to be deployed under centos.
Introduction:
The Node.js platform runs JavaScript code on the backend, so the Node environment must be installed on the machine first .
npm is a package management tool for Node.js ( node package manager ) , which is used to manage the download of modules referenced by Node.js code, which is convenient for solving the dependencies of each module.
Summary of the problem:
In fact, the main reason is that the environment is not satisfied. After upgrading one, and relying on the other, I am really tired. The worst thing is that after upgrading libc.so.6 to version 2.14 ( centos6.5 comes with 2.12 ), it affects the locale of the machine. When svn is updated, Chinese cannot be updated. So I wanted to delete the high-version libc.so.6 dynamic library and restore the old one. As a result, once I deleted the system, I couldn't run any commands. I immediately restored it through the solution found on the Internet, LD_PRELOAD=/lib64/libc-2.12. so ln -s /usr/local/glibc-2.14/lib/libc-2.14.so libc.so.6, the system came to life again; but the second time I didn't give up, I wondered if it was caused by the application occupancy, I deleted it again, but it still didn't work. After a few seconds of restoring it, the system crashed. Fortunately, it is a test system. After cleaning up my emotions, I booted from the centos CD to enter rescue mode and restored it by backing up the original libc.so.6.
Let’s restore it from memory, how I fell into the pit step by step, so that I can reminisce later, or the classmates who see it can bypass some pits:
Because of the dependencies when npm installs modules, python2.7 and gcc-c++ 4.8.0 are required:
First, upgrade python from 2.6 to 2.7 :
Implementation steps:
1. Download the release file of nux :
wget http://li.nux.ro/download/nux/dextop/el6/i386/nux-dextop-release-0-2.el6.nux.noarch.rpm
rpm -ivh nux-dextop-release-0-2.el6.nux.noarch.rpm
yum -y install python27
yum -y install python27-devel
2. Upgrade python
Centos still uses python2.6.* by default , you need to overwrite the python file with the python2.7 file.
cd /usr/bin/
rm -rf python
cp python2.7 python
3. Test
Enter python --version on the command line , if the output shows this is correct:
[root@linuxidc script]# python --version
Python 2.7.3
4、由于yum没有兼容python2.7，需要vi /usr/bin/yum将 #!/usr/bin/python 修改为 #!/usr/bin/python2.6。
然后，npm install时需要gcc-c++-4.8.0以上，在centos6.5默认是gcc-c++-4.4.7。没办法，只能编译升级：
1.下载gcc最新的源码包 wget http://gcc.skazkaforyou.com/releases/gcc-4.9.1/gcc-4.9.1.tar.gz
2.解压缩 tar -xf gcc-4.9.1.tar.gz
3. cd gcc-4.9.1
4.运行download_prerequisites脚本， ./contrib/download_prerequisites ，这个脚本会自动下载所需要的依赖文件和库
5.建立输出目录，将所有的中间文件都放到该目录，
mkdir gcc_temp
cd gcc_temp
6. 运行 ../configure --enable-checking=release --enable-languages=c,c++ --disable-multilib
7. make & make install
然而，gcc升级后，并没有结束，npm install发现引起的依赖关系是libstdc++版本不够高，
/usr/lib64/libstdc++.so.6: version `GLIBCXX_3.4.15'
libstdc++ 检查发现，GLIBCXX 最高只有 3.4.13：
strings /usr/lib64/libstdc++.so.6 | grep GLIBCXX
于是下载了一个 6.0.20 的，替换掉当前使用的 libstdc++
cp /usr/local/lib64/libstdc++.so.6.0.20 /usr/lib64/
ln -s -f /usr/lib64/libstdc++.so.6.0.20 /usr/lib64/libstdc++.so.6
检查一下新的 libstdc++，GLIBCXX 最高到 3.4.20 了
libstdc++.so.6的坑填完之后，就是最挫的地方了，linux的语言环境设置异常，报错：
# locale -a|more
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_COLLATE to default locale: No such file or director
试遍网上的改编码的方式，都不行，其实我也知道，肯定还是glibc版与glibc-common版本不一致造成，找遍度娘谷哥都没找到类似的解决方法，有一个网友跟我的出错一毛一样，但是他也没解决，他说更新了glibc-common仍然无效，此时我有点想回滚了；最悲剧的场面也是因此产生，删除了动态库libc.so.6，服务器直接就挂了，当时就傻了，应该另外找台机器来搞的，没想到依赖关系这么多，捅一堆篓子。
这里其实就是，libstdc++依赖/lib64/libc.so.6: version `GLIBC_2.14'的问题，报错如下：
node: /lib64/libc.so.6: version `GLIBC_2.14' not found (required by /usr/lib64/libstdc++.so.6)
centos6.5的libc.so.6默认版本是2.12，所以，又得升级。。。
于是安装glibc2.14，将glibc更新到glibc2.14
（1）下载
glibc2.14下载地址：
wget http://ftp.gnu.org/gnu/glibc/glibc-2.14.tar.gz
（2）编译
tar -zxvf glibc-2.14.tar.gz
cd glibc-2.14
mkdir build
cd build
../configure --prefix=/usr/local/glibc-2.14
make -j4
make install
方法一：直接生效（建议）
编译.bash_profile下设置：
export LD_PRELOAD=/lib64/libc
export LD_PRELOAD=/usr/local/glibc-2.14/lib/libc-2.14.so
source .bash_profile
在网上查找时，博主是建议用这个，但是糟糕在我选了删除动态库重建链接
方法二：（效果不好，不建议用）
可以先删除软链接：删除/lib64/libc.so.6
cd /lib64
rm libc.so.6
此时libc.so.6被删除，无法执行其他命令，需要用一下命令进行恢复，并重新建立软链接：
export LD_PRELOAD=/lib64/libc
export LD_PRELOAD=/lib64/libc-2.12.so
恢复完成之后执行：
cp /usr/local/glibc-2.14/lib/libc-2.14.so /lib64/libc-2.14.so
ln -s libc-2.14.so libc.so.6
此时，libc.so.6就升级完成。
其实我也就是想回滚libc.so.6包到2.12版本出的问题，过程如下：
cd /lib64
rm libc.so.6
结果系统命令就无法执行，就想先恢复系统，还是用2.14：
LD_PRELOAD=/lib64/libc-2.12.so ln -s /usr/local/glibc-2.14/lib/libc-2.14.so libc.so.6
结果，恢复后几秒，系统就挂了，无法开机了。
下面是拯救过程：思路就是用系统安装镜像（因为我是虚拟机）把libc.so.6
还原成2.12：
进入救援模式后，chroot /mnt/sysimage，结果报错libc.so.6 too short，总之是异常。
然后，我想直接mv 或者删除再拷贝旧版本的libc.so.6都操作失败。
最后想，要不看下当前的挂载情况，看到/mnt/sysimage挂载路径，于是进入
/mnt/sysimage/user/lib64/
删除libc.so.6，再ln -s /libc-2.12.so libc.so.6
之后，重启，至此，系统终于恢复。。。
总结：Centos6.5自带的gcc、python版本都太低，编译升级后各种依赖关系真是让人头疼，而已容易把环境搞得很乱，给维护也带来很大难度，所以程序要求环境的版本比较高，该升centos 7就升吧。我最后也是这么干的，升到centos7后，安装一路顺利，高歌挺进，下一篇写一下整个安装过程。
因水平有限，如有疏漏，还请留言反馈，谢谢~
参考文档：
python2.6升级到2.7
http://www.linuxidc.com/Linux/2014-07/104555.htm
GCC4.7升级到4.9.1
https://www.cppfans.org/1719.html
libstdc++ 的问题
http://blog.41ms.com/post/54.html
libstdc++依赖/lib64/libc.so.6: version `GLIBC_2.14'的问题：
http://rocketeer.leanote.com/post/Glibc%E9%94%99%E8%AF%AF