之前自己做实验全部用的centos7版本的系统，现在要部署到指定服务器，而指定的服务器确是centso6.5版本，因此本来两个命令即可解决的事情，最后遇到了那么多问题需要解决。
1、问题：ModuleNotFoundError: No module named '_ctypes'
解决办法：
yum install libffi-devel -y #有疑问，可能不行
wget http://mirror.centos.org/centos/7/os/x86_64/Packages/libffi-devel-3.0.13-18.el7.x86_64.rpm
rpm -ivh libffi-devel-3.0.13-18.el7.x86_64.rpm
再make install #只的是对python3.7
2、问题：pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Collecting virtualenv
Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/virtualenv/
Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/virtualenv/
Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/virtualenv/
Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/virtualenv/
Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/virtualenv/
Could not fetch URL https://pypi.org/simple/virtualenv/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/virtualenv/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping
Could not find a version that satisfies the requirement virtualenv (from versions: )
No matching distribution found for virtualenv
pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping
解决办法：
wget https://www.openssl.org/source/openssl-1.1.1a.tar.gz
tar -zxvf openssl-1.1.1a.tar.gz
cd openssl-1.1.1a
./config --prefix=/usr/local/openssl no-zlib
make
make install
mv /usr/bin/openssl /usr/bin/openssl.bak #可直接删除，不留备份
mv /usr/include/openssl/ /usr/include/openssl.bak #可直接删除，不留备份
ln -s /usr/local/openssl/include/openssl /usr/include/openssl
ln -s /usr/local/openssl/lib/libssl.so.1.1 /usr/local/lib64/libssl.so
ln -s /usr/local/openssl/bin/openssl /usr/bin/openssl
echo "/usr/local/openssl/lib" >> /etc/ld.so.conf
ldconfig -v
openssl version
ln -s /usr/local/openssl/lib/libssl.so.1.1 /usr/lib64/libssl.so.1.1
ln -s /usr/local/openssl/lib/libcrypto.so.1.1 /usr/lib64/libcrypto.so.1.1
重新编译python.
3、问题：centos ImportError: libSM.so*: cannot open shared object file:
解决办法：
yum whatprovides libSM.so.6
yum install libSM* --setopt=protected_multilib=false
4、问题：centos ImportError: libXrender.so.1: cannot open shared object file:
解决办法：
yum install libXrender
5、问题：centos ImportError: libXrender.so.1: cannot open shared object file:
解决办法：yum install libXext
6、python3.7安装步骤：
yum -y groupinstall "Development tools"
yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel
yum -y install db4-devel libpcap-devel xz-devel
yum install libffi-devel -y
wget https://www.python.org/ftp/python/3.7.0/Python-3.7.0.tar.xz
tar -xvJf Python-3.7.0.tar.xz
mkdir /usr/local/python3
cd Python-3.7.0
./configure --prefix=/usr/local/python3 --with-openssl=/usr/local/openssl --enable-optimizations
make && make install
python3 -V
ln -s /usr/local/python3/bin/python3 /usr/local/bin/python3
ln -s /usr/local/python3/bin/pip3 /usr/local/bin/pip3
python3 -V
pip3 -V
7、安装服务依赖：
pip3 install -U werkzeug
pip3 install gunicorn
pip3 install requests
8、注意：
所有安装包在安装之前都要检查有没有把之前的老版本清理干净。
