Virtualenv: Fail to create a virtualenv on Ubuntu 16.04.

[xiasun]

My system is Ubuntu 16.04. I use sudo apt install virtualenv to install virtualenv successfully.
But when I call virtualenv venv command to create a virtual environment under a path, it shows error below.
There seems to be something wrong with the url of pkg_resources. But I don't know how to fix it.
My virtualenv version is 15.1.0 and my python is of version 2.7.12 and pip 9.0.1. Seems nothing to be updated.

Can anyone give any suggestion what might cause this problem? Thank you!

Log below:
Running virtualenv with interpreter /usr/bin/python2
New python executable in /root/projects/Blog_mini/venv/bin/python2
Also creating executable in /root/projects/Blog_mini/venv/bin/python
Please make sure you remove any previous custom paths from your /root/.pydistutils.cfg file.
Installing setuptools, pkg_resources, pip, wheel...
Complete output from command /root/projects/Blog_mini/venv/bin/python2 - setuptools pkg_resources pip wheel:
Collecting setuptools
Downloading http://mirrors.aliyun.com/pypi/packages/43/41/033a273f9a25cb63050a390ee8397acbc7eae2159195d85f06f17e7be45a/setuptools-38.5.1-py2.py3-none-any.whl (489kB)
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 "/root/projects/Blog_mini/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.aliyun.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
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 /root/projects/Blog_mini/venv/bin/python2 - setuptools pkg_resources pip wheel failed with error code 2

[imbaczek]

add --no-download or --never-download to virtualenv command line or update virtualenv to the latest version