saltstack-formulas/salt-formula

default salt.pkgrepo version - py2 or py3

noelmcloughlin opened this issue · 6 comments

noelmcloughlin commented

After running salt-bootstrap with python 3 support the saltstack repo is correctly defined.

$ cat salt-bootstrap /etc/apt/sources.list.d/saltstack.list 
deb https://repo.saltstack.com/py3/ubuntu/18.04/amd64/latest bionic main

$ head /usr/bin/salt-api 
#!/usr/bin/python3

However subsequent runs of salt-formula.pkgrepo overwrite wrong repo value.

$ cat salt-bootstrap /etc/apt/sources.list.d/saltstack.list 
deb http://repo.saltstack.com/apt/ubuntu/18.04/amd64/latest bionic main

The system gets broken if apt-get install salt-????? is subsequently and usually inadvertently run, because python scripts in /usr/bin are updated to python2.

$ head /usr/bin/salt-api 
#!/usr/bin/python2

This is the problem default value:
$ cat salt-bootstrap /etc/apt/sources.list.d/saltstack.list

salt-formula/salt/osmap.yaml

Line 23 in 7cec4c0

key_url: 'https://repo.saltstack.com/{{ py_ver_dir }}/{{ os_lower }}/{{ osrelease }}/amd64/{{ salt_release }}/SALTSTACK-GPG-KEY.pub'

Maybe the following pillar.example lines should be added to default.yaml.

  # Set this to 'py3' to install the Python 3 packages.
  # If this is not set, the Python 2 packages will be installed by default.
  py_ver: 'py3'
myii commented

@noelmcloughlin This is unfortunate. This py2 to py3 really needs a timeline set (in terms of this org). The issue is that there are py2-based LTS OSes still in support for a while yet. How often are servers updated to the latest and greatest? I wouldn't be surprised to find a sizeable proportion still "holding on".

In terms of this formula, when py_ver was introduced, only py2 packages were being installed here (ref). So to prevent disruption, we still defaulted to py2. Switching to py3 will be a breaking change, so must be considered carefully. Let's hope some of the others chime in with their thoughts.

noelmcloughlin commented

I'm fine leaving as is since I can override by pillar data. The general question is whether we should be nudging people towards python3 via defaults - in this formula and in wider community - the pillar data can be used for less important py2 use case and defaults set to py3 which is more important going forward?

myii commented

@noelmcloughlin The biggest problem is that py2 is the established default. So changing that to py3 is introducing a breaking change, which could lead to some serious issues. Since we've got until Sodium (at the very least), I think we ought to keep py2 as default for a while yet.

noelmcloughlin commented

I'm not asking about dropping py2 support. The computer industry already made its decision to change default to py3. All well maintained OS have changed default to py3 - Linux, MacOS (and maybe Windows) - but still support py2. Changing default to current industry standard should happen asap?

noelmcloughlin commented

py2 was the established default until recently is my point. py3 is now established default.

myii commented

@noelmcloughlin To be clear, in a personal capacity, I've been Python 3 wherever possible. However, in terms of this issue, there are a couple of angles that I'm coming from:

  • Established default for this formula:
    • This formula has been based on Python 2 from the beginning.
    • However many people are using this, it has been with Python 2 as the default.
    • Any change to this (not arguing that the change shouldn't be made), is still a breaking change.
  • Position of SaltStack Formulas within the overall ecosystem:
    • Due to the nature of this organisation, we're always going to have to follow the lead from upstream Salt.
    • We're always constricted by having to support older versions, of OSes and Salt itself (until they EOL).
    • In that subset of minions, what are the Py2/Py3 metrics? Unfortunately, we have no way of determining that.
    • There are still some OSes that don't have Salt Py3 support, such as Fedora (David Murphy on Slack):
      • understand now, could be related to this https://bugzilla.redhat.com/show_bug.cgi?id=1723207
      • in meeting at moment, but will check into it after. Salt in Fedora at the moment is Python 2 based due to issue with Tornado >= 5 on Python 3, hopefully fixed in the Neon Release