How to use repmgr with PostgreSQL 10? Followed the official repmgr document, I set these items to the configuration file:
  shared_preload_libraries = 'repmgr'
  max_wal_senders = 10
  max_replication_slots = 10
  wal_level = 'hot_standby'
  hot_standby = on
  archive_mode = on

However, in the /var/lib/pgsql/10/data/postgresql.conf file, something default as
#wal_level = replica                    # minimal, replica, or logical
                                        # (change requires restart)

Doesn't have hot_standby option.
If I use the config as repmgr document, when I want to create a database or user, alwasy hanging.
createuser -s myuser
createdb -E UNICODE -l en_US.UTF-8 -T template0 mydb -O myuser

But use the default postgresql configuration will work well.
So how to use repmgr with PostgreSQL 10 correctly?
The repmgr doc you linked to says to use wal_level = 'hot_standby' with PG versions 9.5 or older, and wal_level = 'replica' for PG versions 9.6 or newer.

# Ensure WAL files contain enough information to enable read-only queries
# on the standby.
#
#  PostgreSQL 9.5 and earlier: one of 'hot_standby' or 'logical'
#  PostgreSQL 9.6 and later: one of 'replica' or 'logical'
#    ('hot_standby' will still be accepted as an alias for 'replica')
#
# See: https://www.postgresql.org/docs/current/static/runtime-config-wal.html#GUC-WAL-LEVEL


You're using PostgreSQL 10, so replica or logical should be used for this option.