pgbouncer login rejected - postgresql

Question

The second day I can not overcome the connection error through pgbouncer if I use auth_type = hba:
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 | | 7861 kB | pg_default |
/var/lib/pgsql/10/data/pg_hba.conf:
# TYPE DATABASE USER ADDRESS METHOD
host monitoring monitoring 0.0.0.0/0 trust
local monitoring monitoring trust
/etc/pgbouncer/pgbouncer.ini:
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
In pg_hba.conf of pgbouncer I also tried to specify specific addresses of interfaces of the server with mask /32, also mask /8, /16 (real mask of my network segment).
The result is only one: login rejected!
/etc/pgbouncer/hba_bouncer.conf:
host monitoring monitoring 0.0.0.0/0 trust
host monitoring monitoring 127.0.0.1/32 trust
/etc/pgbouncer/userlist.txt:
"monitoring" "monitoring"
Connection attempt:
# 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

Answer 1

We have a use case similar to yours. We are running version 1.12.0 and we ran into the same issue where we also got the "ERROR: login rejected" message.
Turned out after investigation that the permissions on our pg_hba.conf for pg_bouncer was incorrect. Once we gave pgbouncer read permissions, it was working as expected. Unfortunately nothing in the higher logging that we turned on revealed this, and we happened to stumbled across this solution through testing on our own.
Ps. the password hash in the pgbouncer config we had left as "" as we're using trust on our connection. I don't think there is anything different in our config to what you posted otherwise.