Ceph

When I run "make check" on a py3-only system, I get the following failures in the three unit tests that are run using gtest-parallel:

on py3-only I'm seeing:

 58/154 Test  #61: unittest_throttle .......................***Failed    0.20 sec
/usr/bin/env: 'python2': No such file or directory
...
 90/154 Test  #93: unittest_crush ..........................***Failed    0.20 sec
/usr/bin/env: 'python2': No such file or directory
...
105/154 Test #108: unittest_erasure_code_shec_all ..........***Failed    0.20 sec
/usr/bin/env: 'python2': No such file or directory
...

These three tests were migrated to gtest-parallel by https://github.com/ceph/ceph/commit/13bc625b5f06f91031127eccb0c94e0a71c24374 (that commit actually migrated four unit tests to gtest-parallel, but was partially reverted by 814a4a2388f029741bc84bf53bda136f49ea0ddd).

The gtest-parallel script that is generating the error, then, is https://github.com/google/gtest-parallel/blob/master/gtest-parallel - i.e., not even part of the Ceph codebase.

Until gtest-parallel has been fixed to work with Python 3, I don't think we can use it. Also, when and if we do use it, I would argue that it should be packaged first and the build dependency declared in the RPM spec/Debian control files.