0-init/tasks/tz.yml: Why ansible_date_time.tz is a problem

roles/0-init/tasks/tz.yml

@@ -1,3 +1,21 @@
+# 2022-12-30: FYI ansible_date_time.tz provides TZ ABBREVIATIONS (equivalent
+# to 'date +%Z' output) which leads to serious ambiguity -- and not just (A)
+# seasonal EST/EDT ambiguities, or (B) floods of geographic synonyms for the
+# very same time zone!  More Seriously: (C) both commands above output "IST"
+# for both Israel Standard Time (+0200) AND India Standard Time (+0530).  Etc!
+#
+# While Ansible provides 2 other vars that (slightly) help disambiguate
+# (ansible_date_time.tz_dst and ansible_date_time.tz_offset), there's a far
+# better way -- which is to read the System TZ directly from Linux:
+#
+# timedatectl show -p "Timezone" --value
+#
+# This takes care of essentially everything (e.g. output "America/New_York")
+# by checking (1) symlink /etc/localtime then (2) text file /etc/timezone
+# then (3) if neither exist, then "UTC" is declated (correctly!)  One
+# drawback: timedatectl if not easily usable within chroot environments.
+
+
 - name: "'local_tz: {{ local_tz }}' was set by ansible_date_time.tz in /opt/iiab/iiab/vars/default_vars.yml -- e.g. if Ansible finds symlink /etc/localtime -> ../usr/share/zoneinfo/America/New_York -- it will simplify that to 'EDT' (in the summer) or 'EST' (in the winter)"
   command: echo