postgres=# create user monitoring with password 'monitoring';
postgres=# create database monitoring owner monitoring;
postgres=# \du+ monitoring
                   List of roles
 Role name  | Attributes | Member of | Description
------------+------------+-----------+-------------
 monitoring |            | {}        |


postgres=# \l+ monitoring
                                                    List of databases
    Name    |   Owner    | Encoding |   Collate   |    Ctype    | Access privileges |  Size   | Tablespace | Description
------------+------------+----------+-------------+-------------+-------------------+---------+------------+-------------
 monitoring | monitoring | UTF8     | en_US.UTF-8 | en_US.UTF-8 |  

# TYPE  DATABASE        USER            ADDRESS                 METHOD

host    monitoring      monitoring      0.0.0.0/0               trust
local   monitoring      monitoring                              trust

pidfile                 = /var/run/pgbouncer/pgbouncer.pid
reserve_pool_size       = 5
reserve_pool_timeout    = 2
listen_port             = 6432
listen_addr             = *
auth_type               = hba
auth_hba_file           = /etc/pgbouncer/hba_bouncer.conf
auth_file               = /etc/pgbouncer/userlist.txt
logfile                 = /var/log/pgbouncer/pgbouncer.log
log_connections         = 0
log_disconnections      = 0
log_pooler_errors       = 1
max_client_conn         = 5000
server_idle_timeout     = 30
pool_mode               = transaction
server_reset_query      =
admin_users             = root
stats_users             = root,monitoring

[databases]
*                       = client_encoding=UTF8 host=localhost port=5432 pool_size=1000

host    monitoring            monitoring            0.0.0.0/0               trust
host    monitoring            monitoring            127.0.0.1/32            trust

"monitoring" "monitoring"

# psql -U monitoring -p 5432 -h 127.0.0.1
psql (10.1)
Type "help" for help.

monitoring=>

# psql -U monitoring -p 6432 -h 127.0.0.1
psql: ERROR:  login rejected

"monitoring" "monitoring"

2019-08-09 14:01:32.077 23240 WARNING C-0x7873e0: monitoring/monitoring@127.0.0.1:36395 pooler error: login rejected