postgresql-11 installation errors via deb package on ubuntu 16

Hey Guys,

I do not know if this list is also for asking ubuntu package related queries.

We have been recently getting a lot of below errors, as a result of
which the entire postgresql installation gets broken.
the config folder /etc/postgresql/* is empty, initdb fails to
initialize the db and we cannot move forward.

the problem is this is happening only on a certain set of servers, but not all.
so i do not know if this is an issue with the package or anything else?
maybe bad mirror?

i came across a similar issue but this is ages back.
https://stackoverflow.com/questions/2748607/how-to-thoroughly-purge-and-reinstall-postgresql-on-ubuntu
and it was marked close for some reasons.
i get the part that removing everything and reinstalling the package
resolves the issue,


   24  service postgresql stop
   25  rm -rf /etc/postgresql*
   26  rm -rf /var/lib/postgresql*
   27  rm -rf /var/run/postgresql*
   28  rm /var/cache/apt/archives/postgresql-*
   29  apt-get purge postgresql-11
   30  apt-get purge postgresql-client-common
   31  rm -rf /var/log/postgresql*
   32  puppet agent -t --debug --verbose  (this takes care of installation)

and then things are fine from here on.



error messages from /var/log/apt/term.log


Preparing to unpack .../postgresql-11_11.2-1.pgdg16.04+1_amd64.deb ...
Unpacking postgresql-11 (11.2-1.pgdg16.04+1) ...
Processing triggers for postgresql-common (199.pgdg16.04+1) ...
Building PostgreSQL dictionaries from installed myspell/hunspell packages...
Removing obsolete dictionary files:
Setting up postgresql-11 (11.2-1.pgdg16.04+1) ...
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Unescaped left brace in regex is deprecated, passed through in regex;
marked by <-- HERE in m/(?<!\\)\${ <-- HERE ([^}]+)}/ at
/usr/sbin/pam_getenv line 78.
Configuring already existing cluster (configuration:
/etc/postgresql/11/main, data: /var/lib/postgresql/11/main, owner:
112:118)
Error: move_conffile: required configuration file
/var/lib/postgresql/11/main/postgresql.conf does not exist
Error: could not create default cluster. Please create it manually with

  pg_createcluster 11 main --start

----
all installation happen via
deb http://apt.postgresql.org/pub/repos/apt/ xenial-pgdg main 11

this has been really painful to debug, coz i do not know how randomly
we get these errors and sometimes not.



Regards,
Vijay