createdb needs to connect to a database to issue a
CREATE DATABASE SQL statement, and by default it will use:
- a Unix socket domain connection
- the current username from the shell as the database user (so
postgres in your case)
template1 as the database
When it does that, in your case you get this error message:
createdb: could not connect to database template1: FATAL: no
pg_hba.conf entry for host "[local]", user "postgres", database
"template1", SSL off"
It indicates that
postgres as a database user does not have the permission to connect through a Unix domain socket (that's what
This is unusual, since in general, postgres installers on Unix tend to install a
pg_hba.conf starting with this rule:
local all postgres peer
Meaning that the
postgres Unix user has the right to connect locally to any database as the
postgres database user, which suits the needs of administrating databases, including creating new ones.
In fact your
pg_hba.conf does not look like a default one. The simplest way to proceed to immediately solve the problem of database creation would be to edit it, add the above line as the first rule, and reload the postgres service.