Issue: Upgrade from 6.15.4.2. to 6.16 fails due to the lack of connections to the database 

If we start 6.15.4.2 upgrade with the max_connections to 1000 in the /var/lib/pgsql/postgresql.conf , During the upgrade to 6.16 the /var/lib/pgsql/data is backed up to /var/lib/pgsql/data-old and a new config is created in the /var/lib/pgsql/postgresql.conf but with max_connections = 100

During that upgrade it will fail due to the lack of connections to the database even when you have specified it in the /etc/foreman-installer/custom-hiera.yml :
—
postgresql::server::config_entries:
max_connections: 1000
shared_buffers: 6GB
work_mem: 8MB
autovacuum_vacuum_cost_limit: 2000
If we then change the max_connections to 1000 manually and restart the upgrade it will succeed.