1. 无法连接python https服务器
打开防火墙iptables 443端口
2. No package 'libffi' found - fatal error: ffi.h: No such file or directory
yum install libffi libffi-devel
3. pip install lxml error：xslt-config: not found
yum install libxslt-devel libxml2-devel python-devel
4. No module named pkg_resources
curl https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py --insecure | python2.7
上述 --insecure参数可以避免curl进行SSL认证校验
另外CentOS6.2默认安装的Python2.6版本，可以把python2.7安装到/usr/local/下面：
./configure --prefix=/usr/local --enable-unicode=ucs4 --enable-shared LDFLAGS="-Wl,-rpath /usr/local/lib"
by iefreer