Linux安装virtualenvwrapper时报错

1.错误：

[root@iZ8vbi4t4rsi4luhy1v1fkZ lp]# pip3 install virtualenvwrapper
WARNING: pip is being invoked by an old script wrapper. This will fail in a future version of pip.
Please see https://github.com/pypa/pip/issues/5599 for advice on fixing the underlying issue.
To avoid this problem you can invoke Python with '-m pip' instead of running pip directly.
Looking in indexes: http://mirrors.cloud.aliyuncs.com/pypi/simple/
Collecting virtualenvwrapper
  Downloading http://mirrors.cloud.aliyuncs.com/pypi/packages/c1/6b/2f05d73b2d2f2410b48b90d3783a0034c26afa534a4a95ad5f1178d61191/virtualenvwrapper-4.8.4.tar.gz (334 kB)
     |████████████████████████████████| 334 kB 42.3 MB/s 
    ERROR: Command errored out with exit status 1:
     command: /usr/bin/python3.6 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-sja5p032/virtualenvwrapper/setup.py'"'"'; __file__='"'"'/tmp/pip-install-sja5p032/virtualenvwrapper/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-install-sja5p032/virtualenvwrapper/pip-egg-info
         cwd: /tmp/pip-install-sja5p032/virtualenvwrapper/
    Complete output (34 lines):
    WARNING: The wheel package is not available.
    WARNING: The repository located at mirrors.cloud.aliyuncs.com is not a trusted or secure host and is being ignored. If this repository is available via HTTPS we recommend you use HTTPS instead, otherwise you may silence this warning and allow it anyway with '--trusted-host mirrors.cloud.aliyuncs.com'.
    ERROR: Could not find a version that satisfies the requirement pbr (from versions: none)
    ERROR: No matching distribution found for pbr
    Traceback (most recent call last):
      File "/usr/local/lib/python3.6/site-packages/setuptools/installer.py", line 128, in fetch_build_egg
        subprocess.check_call(cmd)
      File "/usr/lib64/python3.6/subprocess.py", line 311, in check_call
        raise CalledProcessError(retcode, cmd)
    subprocess.CalledProcessError: Command '['/usr/bin/python3.6', '-m', 'pip', '--disable-pip-version-check', 'wheel', '--no-deps', '-w', '/tmp/tmpwemsl_v0', '--quiet', '--index-url', 'http://mirrors.cloud.aliyuncs.com/pypi/simple/', 'pbr']' returned non-zero exit status 1.
    
    During handling of the above exception, another exception occurred:
    
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-install-sja5p032/virtualenvwrapper/setup.py", line 7, in <module>
        pbr=True,
      File "/usr/local/lib/python3.6/site-packages/setuptools/__init__.py", line 143, in setup
        _install_setup_requires(attrs)
      File "/usr/local/lib/python3.6/site-packages/setuptools/__init__.py", line 138, in _install_setup_requires
        dist.fetch_build_eggs(dist.setup_requires)
      File "/usr/local/lib/python3.6/site-packages/setuptools/dist.py", line 698, in fetch_build_eggs
        replace_conflicting=True,
      File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 783, in resolve
        replace_conflicting=replace_conflicting
      File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 1066, in best_match
        return self.obtain(req, installer)
      File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 1078, in obtain
        return installer(requirement)
      File "/usr/local/lib/python3.6/site-packages/setuptools/dist.py", line 754, in fetch_build_egg
        return fetch_build_egg(self, req)
      File "/usr/local/lib/python3.6/site-packages/setuptools/installer.py", line 130, in fetch_build_egg
        raise DistutilsError(str(e))
    distutils.errors.DistutilsError: Command '['/usr/bin/python3.6', '-m', 'pip', '--disable-pip-version-check', 'wheel', '--no-deps', '-w', '/tmp/tmpwemsl_v0', '--quiet', '--index-url', 'http://mirrors.cloud.aliyuncs.com/pypi/simple/', 'pbr']' returned non-zero exit status 1.
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.

2.一定要往上找ERROR，找到  ERROR: No matching distribution found for pbr

3.其错误原因是没有安装pbr，通过pip3 install pbr，在执行   pip3 install virtualenvwrapper 就不会报错了