按这个链接操作了一下，还有有问题，我试了3个版本都遇到同样的问题（CentOS(7.9, 7.6, 7.4)），而且都是围绕着ssl的，

1. 编译阶段遇到的ssl问题
   Message: 'späm’
   Arguments: ()
   Got an error:
   [SSL: SSLV3_ALERT_CERTIFICATE_EXPIRED] sslv3 alert certificate expired (_ssl.c:833)
   然后我用这串命令流重现安装了ssl证书，编译阶段是ssl问题就解决了
   cd /usr/local/src
   wget https://www.openssl.org/source/openssl-1.1.1k.tar.gz
   tar -xf openssl-1.1.1k.tar.gz
   cd openssl-1.1.1k
   ./config --prefix=/usr/local/openssl shared zlib &&make && make install
   mv /usr/bin/openssl /usr/bin/openssl.bak
   mv /usr/include/openssl /usr/include/openssl.bak
   ln -s /usr/local/openssl/bin/openssl /usr/bin/openssl
   ln -s /usr/local/openssl/include/openssl /usr/include/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

2. pip install virtualenv 是遇到这个问题
   [root@localhost Python-3.6.5]# pip3.6 install virtualenv
   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.python.org/simple/virtualenv/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host=‘pypi.python.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
   [root@localhost Python-3.6.5]#
   然后我用下面命令流解决了这个问题
   mkdir ~/.pip
   vim ~/.pip/pip.conf
   [global]
   index-url=http://mirrors.aliyun.com/pypi/simple/
   [install]
   trusted-host=mirrors.aliyun.com

3. 然后实例化virtualenv的时候又遇到这个问题
   [deploy@localhost ~]$ virtualenv -p /usr/local/bin/python3.6 .py3-a2.5-env
   Traceback (most recent call last):
   File “/usr/local/bin/virtualenv”, line 7, in
   from virtualenv.main import run_with_catch
   File “/usr/local/lib/python3.6/site-packages/virtualenv/init.py”, line 3, in
   from .run import cli_run, session_via_cli
   File “/usr/local/lib/python3.6/site-packages/virtualenv/run/init.py”, line 11, in
   from …seed.wheels.periodic_update import manual_upgrade
   File “/usr/local/lib/python3.6/site-packages/virtualenv/seed/wheels/init.py”, line 3, in
   from .acquire import get_wheel, pip_wheel_env_run
   File “/usr/local/lib/python3.6/site-packages/virtualenv/seed/wheels/acquire.py”, line 12, in
   from .bundle import from_bundle
   File “/usr/local/lib/python3.6/site-packages/virtualenv/seed/wheels/bundle.py”, line 4, in
   from .periodic_update import periodic_update
   File “/usr/local/lib/python3.6/site-packages/virtualenv/seed/wheels/periodic_update.py”, line 10, in
   import ssl
   File “/usr/local/lib/python3.6/ssl.py”, line 101, in
   import _ssl # if we can’t import it, let the error propagate
   ModuleNotFoundError: No module named ‘_ssl’
   [deploy@localhost ~]$
   好艰难啊！