Hi,

Are you using different machine when installing each Odoo Instance and Postgres, or do you put it in the same machine?

I will assume that this is the first time you are installing Odoo and postgresql in you machine. In order to connect Odoo with Postgresql, if you are installed both in the same machine, follow the step below :

1. From CLI, switch from your superuser user typing su - postgres. This will switch you from root user to postgres user
2. Access the psql instance by typing psql
3. Then, create a user that later will be used as connection between postgres and odoo. Type these queries below (if you have trouble executing all of these, try to execute line by line : 
   
   

   CREATE USER your-desired-username WITH PASSWORD 'your-desired-password';
   ALTER USER your-desired-username WITH SUPERUSER;
   ALTER USER your-desired-username WITH CREATEROLE;
   ALTER USER your-desired-username WITH CREATEDB;
   ALTER ROLE your-desired-username VALID UNTIL 'infinity’;

4. After that, exit the database by typing exit.
5. Then, go to odoo.conf configuration file by typing nano /etc/odoo/odoo.conf
6. Enter these basic configuration below :
   
   

   admin_passwd = your-admin-pass
   data_dir = /var/lib/odoo/.local/share/Odoo/
   db_host = False
   db_port = False
   db_password = False
   db_user = your-desired-username
   log_level = debug

   
   save the config by pressing ctrl + x and then y
7. Restart odoo service by typing service odoo restart
8. Now, go to your browser and access the IP of the machine that host odoo using default odoo port 8069 (example, 192.168.1.1:8069)

Best regards,
Altela (altelasoftware.com)