[Flask] 安装virtualenv时候出现的问题

1.HTTPError: 404 Client Error: Not Found for url: ...的错误

ubuntu@VM-0-6-ubuntu:~/myprojects$ virtualenv venv
Running virtualenv with interpreter /usr/bin/python2
New python executable in /home/ubuntu/myprojects/venv/bin/python2
Also creating executable in /home/ubuntu/myprojects/venv/bin/python
Please make sure you remove any previous custom paths from your /home/ubuntu/.pydistutils.cfg file.
Installing setuptools, pkg_resources, pip, wheel...
  Complete output from command /home/ubuntu/myprojects/venv/bin/python2 - setuptools pkg_resources pip wheel:  Collecting setuptools
  Downloading http://mirrors.tencentyun.com/pypi/packages/6a/9a/50fadfd53ec909e4399b67c74cc7f4e883488035cfcdb90b685758fa8b34/setuptools-41.4.0-py2.py3-none-any.whl (580kB)
Collecting pkg_resources
Exception:
Traceback (most recent call last):
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/basecommand.py", line 209, in main
    status = self.run(options, args)
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/commands/install.py", line 328, in run
    wb.build(autobuilding=True)
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/wheel.py", line 748, in build
    self.requirement_set.prepare_files(self.finder)
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/req/req_set.py", line 360, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/req/req_set.py", line 512, in _prepare_file
    finder, self.upgrade, require_hashes)
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/req/req_install.py", line 273, in populate_link
    self.link = finder.find_requirement(self, upgrade)
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/index.py", line 442, in find_requirement
    all_candidates = self.find_all_candidates(req.name)
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/index.py", line 400, in find_all_candidates
    for page in self._get_pages(url_locations, project_name):
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/index.py", line 545, in _get_pages
    page = self._get_page(location)
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/index.py", line 648, in _get_page
    return HTMLPage.get_page(link, session=self.session)
  File "/usr/share/python-wheels/pip-8.1.1-py2.py3-none-any.whl/pip/index.py", line 760, in get_page
    resp.raise_for_status()
  File "/home/ubuntu/myprojects/venv/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/models.py", line 840, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
HTTPError: 404 Client Error: Not Found for url: http://mirrors.tencentyun.com/pypi/simple/pkg-resources/
----------------------------------------
...Installing setuptools, pkg_resources, pip, wheel...done.
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 2363, in <module>
    main()
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 719, in main
    symlink=options.symlink)
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 988, in create_environment
    download=download,
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 918, in install_wheel
    call_subprocess(cmd, show_stdout=False, extra_env=env, stdin=SCRIPT)
  File "/usr/lib/python3/dist-packages/virtualenv.py", line 812, in call_subprocess
    % (cmd_desc, proc.returncode))
OSError: Command /home/ubuntu/myprojects/venv/bin/python2 - setuptools pkg_resources pip wheel failed with error code 2

解决方案：修改pip源

vim ~/.pip/pip.conf打开pip配置文件: 

[global]
index-url = http://e.pypi.python.org/simple

注意点：

vim ~/.pip/pip.conf 是打开当前用户下的pip配置文件
百度说修改/root/.pip/pip.conf文件，于是我用root账户进行了修改
这样其实是修改root账户的pip配置文件，这样会导致在当前用户下无效果，这点要注意。