[Starlingx-discuss] Python2 -> Python3

[Dean Troyer]

On 7/3/19 4:07 PM, Saul Wold wrote:
> The current proposal seems to be to completely convert the base 
> CentOS7.6 system level python to use python3, this carries a high risk 
> factor as changing out all system-level python code could have a cascade 
> effect on system functionality and additional dependencies. While 

Changing the distro/system Python version out from under the rest of the 
distro seems like an enormous time sink, much less a significant 
reliability risk.

> A better solution would be to build python3 and the associated 
> requirements from the existing RHEL EPEL (Extra Packages for Enterprise 
> Linux) Source RPMs repo and install them into the ISO. This version 
> correctly installs in a segregated directory tree.

We would probably want to run a significant subset of the upstream 
OpenStack testing on this combination as it is not (AFAIK) tested there. 
  But this is true of any runtime + distro combination that is not in 
the fairly short list of combinations that upstream OpenStack actively 
tests.

> Another option would be to delay the actual python2 conversion to 
> StarlingX 4.0, the OpenStack Train release will still support python2.

One downside to this is it leaves us no margin to defer the change 
again, this is our second chance as it were.  OpenStack U (as of now) is 
likely to drop py2 support as a guarantee across-the-board.

> There is still work that is needed beyond the conversion of the python 
> code itself to things like RPM specfiles data and other source code 
> (such as, C code that has #includes of python2.7). It's not clear to me 
> how much functional testing with python3 has occurred for the flock 
> beyond what Dean has started with devstack.

I managed to get the fault services running on py3, sysinv fell over 
during the dbsync in my quick post-PTG trial run.  That is as far as I 
took it.  Anyone who wants to try can pick out the local.conf I posted [0]

dt

[0] http://paste.openstack.org/show/753844/

-- 
Dean Troyer
dtroyer at gmail.com