Explain Ansible modules used w/ 4+1 packages {python3-*, virtualenv}

roles/2-common/tasks/packages.yml

@@ -30,8 +30,8 @@
       #- openssh-server    # ssh (Raspbian) or openssh-server (other OS's) already installed by 1-prep's roles/sshd/tasks/main.yml
       - pandoc             # For /usr/bin/iiab-refresh-wiki-docs
       - pastebinit         # For /usr/bin/iiab-diagnostics
-      #- python3-pip       # Already installed by /opt/iiab/iiab/scripts/ansible -- this auto-installs 'python3-setuptools' and 'python3' etc
+      #- python3-pip       # 2021-07-29: Already installed by /opt/iiab/iiab/scripts/ansible -- this auto-installs 'python3-setuptools' and 'python3' etc
-      - python3-venv       # 2021-07-29: Unlike Debian 11, this is required on Ubuntu 20.04 (where packages like python3-pymysql -> python3 don't drag in 'python3-venv') -- for roles like {calibre-web, jupyterhub, lokole} -- whereas roles/kalite uses (virtual) package 'virtualenv' for Python 2
+      - python3-venv       # 2021-07-29: Unlike Debian 11, this is required on Ubuntu 20.04 (where packages like python3-pymysql -> python3 don't drag in 'python3-venv') -- for Ansible module 'pip' used in roles like {calibre-web, jupyterhub, lokole} -- whereas roles/kalite uses it with (virtual) package 'virtualenv' for Python 2
       - rsync
       #- screen            # Installed by 1-prep's roles/iiab-admin/tasks/access.yml
       - sqlite3

roles/kalite/tasks/install.yml

@@ -16,7 +16,7 @@
     name:
       - python2
       - python-setuptools    # Provides setuptools-44 on recent OS's (last version compatible with python2)
-      - virtualenv           # Provides venv for python2 -- compare python3-venv in scripts/ansible
+      - virtualenv           # For Ansible module 'pip' when used with 'virtualenv_command: /usr/bin/virtualenv' and 'virtualenv_python: python2.7' -- compare package 'python3-venv' used by roles {calibre-web, jupyterhub, lokole}
     state: present
   #when: not (is_debian_9 or is_debian_10 or is_ubuntu_16 or is_ubuntu_17 or is_ubuntu_18 or is_ubuntu_19)
   # 2020-03-31: Testing for {is_raspbian_9, is_raspbian_10} is not currently nec, as testing for {is_debian_9, is_debian_10} covers that already.

roles/munin/tasks/install.yml

@@ -6,7 +6,7 @@
       - munin
       - munin-node
       - munin-plugins-extra
-      - python3-passlib
+      - python3-passlib    # For Ansible module 'htpasswd' in Ansible collection community.general -- used just below
     state: present
 
 - name: Establish username/password Admin/changeme in /etc/munin/munin-htpasswd

roles/mysql/tasks/install.yml

@@ -12,7 +12,7 @@
       - mariadb-client
       #- php{{ php_version }}-common    # Auto-installed as an apt dependency.  REGARDLESS: php{{ php_version }}-common superset php{{ php_version }}-cli is auto-installed by php{{ php_version }}-fpm in nginx/tasks/install.yml
       - php{{ php_version }}-mysql      # Likewise installed in nextcloud/tasks/install.yml, pbx/tasks/freepbx_dependencies.yml, wordpress/tasks/install.yml
-      - python3-pymysql                 # 2021-07-29: Required by MySQL roles {mediawiki, nextcloud, wordpress} and possibly {elgg, pbx}
+      - python3-pymysql                 # For Ansible modules {mysql_db, mysql_user available} in Ansible collection community.mysql -- used in MySQL roles {mediawiki, nextcloud, wordpress} and possibly {elgg, pbx}
     state: present
 
 # 2020-07-11:

roles/postgresql/tasks/install.yml

@@ -3,7 +3,7 @@
     name:
       - postgresql
       - postgresql-client
-      - python3-psycopg2    # Moodle install fails without this
+      - python3-psycopg2    # For Ansible modules {postgresql_db, postgresql_user} in Ansible collection community.postgresql -- used in moodle/tasks/install.yml
     state: present
 
 - name: Install /etc/systemd/system/postgresql-iiab.service from template (0644 by default)

scripts/ansible

@@ -156,7 +156,7 @@ $APT_PATH/apt -y install python3-pip
 
 # 2021-07-29:
 # 'python3-packaging' dropped for now
-# 'python3-pymysql' (drags in 'python3' which drags in 'python3-venv' on Debian 11 but not on Ubuntu 20.04) moved to roles/mysql/tasks/install.yml
+# 'python3-pymysql' (drags in 'python3' which drags in 'python3-venv' on Debian 11 but not on Ubuntu 20.04) -- moved to roles/mysql/tasks/install.yml
 # 'python3-psycopg2' moved to roles/postgresql/tasks/install.yml
 # 'python3-passlib' moved to roles/munin/tasks/install.yml
 # 'python3-venv' moved to roles/2-common/tasks/packages.yml