mininet中安装ryu过程中出现的问题

安装过程看这里：http://linton.tw/2014/02/15/note-install-ryu-36-sdn-framework/

用pip安装完后运行命令ryu-manager后，出现如下错误：

<pre class="python" name="code">root@ubuntu:/home/zsj# ryu --versionTraceback (most recent call last):  File "/usr/local/bin/ryu", line 5, in <module>    from pkg_resources import load_entry_point  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2749, in <module>    working_set = WorkingSet._build_master()  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 446, in _build_master    return cls._build_from_requirements(__requires__)  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 459, in _build_from_requirements    dists = ws.resolve(reqs, Environment())  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 632, in resolve    raise VersionConflict(dist,req) # XXX put more info herepkg_resources.VersionConflict: (six 1.5.2 (/usr/lib/python2.7/dist-packages), Requirement.parse('six>=1.9.0'))

解决办法：

<pre class="python" name="code">root@ubuntu:/home/zsj# pip install --upgrade sixDownloading/unpacking six from https://pypi.python.org/packages/3.3/s/six/six-1.9.0-py2.py3-none-any.whl#md5=9ac7e129a80f72d6fc1f0216f6e9627b  Downloading six-1.9.0-py2.py3-none-any.whlInstalling collected packages: six  Found existing installation: six 1.5.2    Not uninstalling six at /usr/lib/python2.7/dist-packages, owned by OSSuccessfully installed sixCleaning up...root@ubuntu:/home/zsj# ryu --versionryu 3.23.2