pip安装或更新报错：SSLError

更新pip时候出现报错

[root@node01 ~]# pip install --upgrade pip
Collecting pip
  Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno 101] Network is unreachable',)': /packages/5c/e0/be401c003291b56efc55aeba6a80ab790d3d4cece2778288d65323009420/pip-19.1.1-py2.py3-none-any.whl
Exception:
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/lib/python2.7/site-packages/pip/commands/install.py", line 307, in run
    requirement_set.prepare_files(finder)
  File "/usr/lib/python2.7/site-packages/pip/req/req_set.py", line 370, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "/usr/lib/python2.7/site-packages/pip/req/req_set.py", line 587, in _prepare_file
    session=self.session, hashes=hashes)
  File "/usr/lib/python2.7/site-packages/pip/download.py", line 810, in unpack_url
    hashes=hashes
  File "/usr/lib/python2.7/site-packages/pip/download.py", line 649, in unpack_http_url
    hashes)
  File "/usr/lib/python2.7/site-packages/pip/download.py", line 842, in _download_http_url
    stream=True,
  File "/usr/lib/python2.7/site-packages/pip/_vendor/requests/sessions.py", line 487, in get
    return self.request('GET', url, **kwargs)
  File "/usr/lib/python2.7/site-packages/pip/download.py", line 378, in request
    return super(PipSession, self).request(method, url, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/pip/_vendor/requests/sessions.py", line 475, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/lib/python2.7/site-packages/pip/_vendor/requests/sessions.py", line 585, in send
    r = adapter.send(request, **kwargs)
  File "/usr/lib/python2.7/site-packages/pip/_vendor/cachecontrol/adapter.py", line 46, in send
    resp = super(CacheControlAdapter, self).send(request, **kw)
  File "/usr/lib/python2.7/site-packages/pip/_vendor/requests/adapters.py", line 477, in send
    raise SSLError(e, request=request)
SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:579)

解决办法：

[root@node01 ~]# pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org  --upgrade  pip

如果是安装第三方包出现这个问题，即是将pip改为包名即可

参考博客：
https://www.jianshu.com/p/49b74f6c6b69