Remove support for Python 2 on the host

Drops support for creating Python 2 virtualenvs in bootstrap-servers,
and looking for a python2 interpreter in the kolla-ansible script.

Also forces the use of Python 3 as the remote interpreter in CI on
Debian and Ubuntu hosts, since they typically symlink the unversioned
interpreter to python2.7.

Change-Id: Id0e977de381e7faafed738674a140ba36184727e
Partially-Implements: blueprint drop-py2-support

ansible/roles/baremetal/defaults/main.yml

@@ -49,22 +49,20 @@ easy_install_available: >-
 
 # Version of python used to execute Ansible modules.
 host_python_version: "{{ ansible_python.version.major }}.{{ ansible_python.version.minor }}"
-host_python_major_version: "{{ ansible_python.version.major }}"
 
 debian_pkg_install:
  - "{{ docker_apt_package }}"
  - git
- - "python{% if host_python_major_version == '3' %}3{% endif %}-setuptools"
- - "{% if not easy_install_available %}python{% if host_python_major_version == '3' %}3{% endif %}-pip{% endif %}"
- - "{% if virtualenv is not none %}python{% if host_python_major_version == '3' %}3{% endif %}-virtualenv{% endif %}"
+ - "python3-setuptools"
+ - "{% if not easy_install_available %}python3-pip{% endif %}"
+ - "{% if virtualenv is not none %}python3-virtualenv{% endif %}"
  - "{% if enable_host_ntp | bool %}ntp{% endif %}"
 
 redhat_pkg_install:
  - "{{ docker_yum_package }}"
  - git
- - "{% if host_python_major_version == '2' %}python-setuptools{% endif %}"
- - "{% if not easy_install_available %}python{{ host_python_major_version }}-pip{% endif %}"
- - "{% if virtualenv is not none %}python{{ host_python_major_version }}-virtualenv{% endif %}"
+ - "{% if not easy_install_available %}python3-pip{% endif %}"
+ - "{% if virtualenv is not none %}python3-virtualenv{% endif %}"
  - "{% if enable_host_ntp | bool %}ntp{% endif %}"
  - sudo
 

ansible/roles/baremetal/tasks/install.yml

@@ -125,7 +125,7 @@
   pip:
     # NOTE(hrw) docker 2.4.2 is in kolla-ansible requirements
     name: docker>=2.4.2
-    executable: "{{ virtualenv is none | ternary('pip' ~ host_python_major_version, omit) }}"
+    executable: "{{ virtualenv is none | ternary('pip3', omit) }}"
     virtualenv: "{{ virtualenv is none | ternary(omit, virtualenv) }}"
     virtualenv_site_packages: "{{ virtualenv is none | ternary(omit, virtualenv_site_packages) }}"
     virtualenv_python: "{{ virtualenv is none | ternary(omit, 'python' ~ host_python_version) }}"

ansible/roles/neutron/defaults/main.yml

@@ -215,17 +215,7 @@ ironic_neutron_agent_image: "{{ docker_registry ~ '/' if docker_registry else ''
 ironic_neutron_agent_tag: "{{ neutron_tag }}"
 ironic_neutron_agent_image_full: "{{ ironic_neutron_agent_image }}:{{ ironic_neutron_agent_tag }}"
 
-# TODO(wszumski): This is a workaround for: https://bugs.launchpad.net/oslo.rootwrap/+bug/1760471
-# and should be removed once we use python 3 for all distibutions.
-neutron_agent_dimensions_python2:
-  # Values taken from TripleO: https://review.opendev.org/#/c/651137/
-  ulimits:
-    nofile:
-      soft: 16384
-      hard: 16384
-
-neutron_agent_dimensions: >-
-  {{ default_container_dimensions | combine(neutron_agent_dimensions_python2 if distro_python_version is version('3.0', '<') else {}) }}
+neutron_agent_dimensions: "{{ default_container_dimensions }}"
 
 neutron_dhcp_agent_dimensions: "{{ neutron_agent_dimensions }}"
 neutron_l3_agent_dimensions: "{{ neutron_agent_dimensions }}"

tests/templates/globals-default.j2

@@ -1,4 +1,10 @@
 ---
+{% if ansible_os_family == 'Debian' %}
+# Force the use of python3 on Debian and Ubuntu remote hosts. These distros
+# typically have an unversioned Python interpreter which links to python2.7.
+ansible_python_interpreter: /usr/bin/python3
+{% endif %}
+
 kolla_base_distro: "{{ base_distro }}"
 kolla_install_type: "{{ install_type }}"
 network_interface: "{{ api_interface_name }}"

tools/kolla-ansible

@@ -15,10 +15,7 @@ function check_ansible_compatibility {
 }
 
 function find_base_dir {
-    # $1: Python interpreter
-    local python
-    python=$1
-    local real_path=$($python -c "import os;print(os.path.realpath('$0'))")
+    local real_path=$(python3 -c "import os;print(os.path.realpath('$0'))")
     local dir_name="$(dirname "$real_path")"
     if [ -z "$SNAP" ]; then
         if [[ ${dir_name} == "/usr/bin" ]]; then
@@ -142,21 +139,15 @@ LONG_OPTS="help,inventory:,playbook:,skip-tags:,tags:,key:,extra:,verbose,config
 RAW_ARGS="$*"
 ARGS=$(getopt -o "${SHORT_OPTS}" -l "${LONG_OPTS}" --name "$0" -- "$@") || { usage >&2; exit 2; }
 
-# Detect which python interpreter to use.
-for python in python3 python2; do
-    if $python -c 'import kolla_ansible' &>/dev/null; then
-        PYTHON=$python
-        break
-    fi
-done
-if [[ -z $PYTHON ]]; then
+# Check for existence of kolla_ansible module using python3 interpreter.
+if ! python3 -c 'import kolla_ansible' &>/dev/null; then
     echo "ERROR: kolla_ansible has to be available in the PYTHONPATH (e.g. installed)" >&2
     exit 1
 fi
 
 eval set -- "$ARGS"
 
-find_base_dir $PYTHON
+find_base_dir
 
 INVENTORY="${BASEDIR}/ansible/inventory/all-in-one"
 PLAYBOOK="${BASEDIR}/ansible/site.yml"