Kong fails to start with the error "password authentication failed for user"

After installing and trying to start Kong, the below error is thrown:

Error: /usr/local/share/lua/5.1/kong/cmd/start.lua:156: 
nginx: [error] init_by_lua error: /usr/local/share/lua/5.1/kong/init.lua:462: [PostgreSQL error] failed to retrieve PostgreSQL server_version_num: FATAL: password authentication failed for user "root"
stack traceback:
	[C]: in function 'assert'
	/usr/local/share/lua/5.1/kong/init.lua:462: in function 'init'
	init_by_lua:3: in main chunk
a:3: in main chunk

  Run with --v (verbose) or --vv (debug) for more details
waiting for db

You will notice the migrations jobs have run, however Kong fails to start using the same db account. A review of the Postgres logs will show a similar error

2025-12-15 21:00:00 UTC:10.10.100.190(26680):root@kong:[10839]:FATAL: password authentication failed for user "root"
2025-12-15 21:00:00 UTC:10.10.100.190(26680):root@kong:[10839]:DETAIL: Password does not match for user "root".

The issue stems from the handling of special characters in the Postgres password. In particular, if the password contains a hash mark (#), Kong treats everything after it as a comment when parsing kong.conf, which truncates the password and produces this error.

This only affects password values set in the kong.conf file. If the password is instead supplied via the environment variable KONG_PG_PASSWORD, the hash mark is not interpreted as a comment and the value is passed through correctly, so no change is needed in that case.

For passwords set in kong.conf, rather than changing the password to remove the hash mark, escape it as \# in the file. This preserves the real password (including the # character) while preventing Kong from truncating it at parse time.