tox: use Python 3 where possible

Time to say goodbye for Python 2

Depends-On: https://review.opendev.org/693356

Change-Id: I5f23da932df70bf17d09d42420ac408221d0e02f

tools/setup_RedHat.sh

@@ -14,7 +14,7 @@ gpgcheck=1
 gpgkey=$DOCKER_REPOS_MIRROR_URL/centos/gpg
 EOF
 
-sudo yum -y install docker-ce
+sudo yum -y install docker-ce python3
 
 # Disable SELinux
 setenforce 0

tox.ini

@@ -1,9 +1,10 @@
 [tox]
 minversion = 2.5.0
 skipsdist = True
-envlist = pep8,py27,py37,pypy
+envlist = pep8,py37,pypy
 
 [testenv]
+basepython = python3
 usedevelop=True
 whitelist_externals = find
                       rm
@@ -20,11 +21,22 @@ commands =
   stestr run {posargs}
   stestr slowest
 
+[testenv:py27]
+basepython = python2.7
+
+[testenv:py36]
+basepython = python3.6
+
+[testenv:py37]
+basepython = python3.7
+
+[testenv:pypy]
+basepython = pypy
+
 [testenv:debug]
 commands = oslo_debug_helper -t kolla/tests {posargs}
 
 [testenv:cover]
-basepython = python3
 setenv = VIRTUAL_ENV={envdir}
          NOSE_WITH_COVERAGE=1
          NOSE_COVER_BRANCHES=1
@@ -39,7 +51,6 @@ commands =
     coverage report --show-missing
 
 [testenv:pep8]
-basepython = python3
 deps =
     {[testenv]deps}
     yamllint
@@ -56,7 +67,6 @@ commands =
 commands = bandit --skip B303 -r docker kolla tests tools
 
 [testenv:venv]
-basepython = python3
 deps =
     -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/test-requirements.txt
@@ -64,7 +74,6 @@ deps =
 commands = {posargs}
 
 [testenv:docs]
-basepython = python3
 deps =
     -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/requirements.txt
@@ -76,7 +85,6 @@ commands =
   sphinx-build -W --keep-going -b html doc/source doc/build/html
 
 [testenv:pdf-docs]
-basepython = python3
 whitelist_externals = make
 deps = {[testenv:docs]deps}
 commands =
@@ -149,14 +157,12 @@ commands=
   oslo-config-generator --config-file etc/oslo-config-generator/kolla-build.conf
 
 [testenv:releasenotes]
-basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands =
   rm -rf releasenotes/build
   sphinx-build -a -E -W -d releasenotes/build/doctrees --keep-going -b html releasenotes/source releasenotes/build/html
 
 [testenv:bindep]
-basepython = python3
 # Do not install any requirements. We want this to be fast and work even if
 # system dependencies are missing, since it's used to tell you what system
 # dependencies are missing! This also means that bindep must be installed
@@ -173,7 +179,6 @@ exclude=.eggs,.git,.tox,doc
 local-check-factory = kolla.hacking.checks.factory
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt