build error

[wlm328cs]

Hello everybody, i build contrail-vrouter and has the follow questions, Does anyone know why? thanks very much (OS: centos 7, install in virtual machine, kernel: 3.10.0-957.10.1.el7.x86_64 gcc version: 4.8.5 scons version(too high? SConstruct need change?): script: v3.0.5.a56bbd8c09fb219ab8a9673330ffcd55279219d0, 2019-03-26 23:16:31, by bdeegan on kufra engine: v3.0.5.a56bbd8c09fb219ab8a9673330ffcd55279219d0, 2019-03-26 23:16:31, by bdeegan on kufra engine path: ['/usr/lib/scons/SCons'] python version:3.5(default python is 2.7, the result is the same...) Have A OSError, but I don't know why??? )

[root@MiWiFi-R3A-srv vr]# scons vrouter scons: Reading SConscript files ... OSError: [Errno 17] File exists: File "/home/wlm/vr/SConstruct", line 20: SConscript(dirs=['src/contrail-common', 'controller', 'vrouter']) File "/usr/lib/scons/SCons/Script/SConscript.py", line 668: return method(*args, **kw) File "/usr/lib/scons/SCons/Script/SConscript.py", line 605: return _SConscript(self.fs, *files, **subst_kw) File "/usr/lib/scons/SCons/Script/SConscript.py", line 286: exec(compile(scriptdata, scriptname, 'exec'), call_stack[-1].globals) File "/home/wlm/vr/controller/SConscript", line 17: SConscript(dirs=['lib', 'src']) File "/usr/lib/scons/SCons/Script/SConscript.py", line 668: return method(*args, **kw) File "/usr/lib/scons/SCons/Script/SConscript.py", line 605: return _SConscript(self.fs, *files, **subst_kw) File "/usr/lib/scons/SCons/Script/SConscript.py", line 286: exec(compile(scriptdata, scriptname, 'exec'), call_stack[-1].globals) File "/home/wlm/vr/controller/lib/SConscript", line 46: SConscript(dirs = dir, variant_dir = '#/build/third_party/' + dir) File "/usr/lib/scons/SCons/Script/SConscript.py", line 668: return method(*args, **kw) File "/usr/lib/scons/SCons/Script/SConscript.py", line 605: return _SConscript(self.fs, *files, **subst_kw) File "/usr/lib/scons/SCons/Script/SConscript.py", line 286: exec(compile(scriptdata, scriptname, 'exec'), call_stack[-1].globals) File "/home/wlm/vr/build/third_party/openvswitch/SConscript", line 34: Symlink([Dir('#/build/include/openvswitch/include')], [Dir(vpath + '/include')]) File "/home/wlm/vr/build/third_party/openvswitch/SConscript", line 32: os.symlink(source[0].abspath, target[0].abspath)