Impossible to use odoo with postgresql

Hi

Impossible to connect odoo to postgresql

the name of postgres is db, so its ok

this is the log and it is not working

Database connection failure: could not translate host name “db” to address: Name or service not known

Database connection failure: could not translate host name “db” to address: Name or service not known

Database connection failure: could not translate host name “db” to address: Name or service not known

Database connection failure: could not translate host name “db” to address: Name or service not known

Database connection failure: could not translate host name “db” to address: Name or service not known

Database connection failure: could not translate host name “db” to address: Name or service not known

Database connection failure: could not translate host name “db” to address: Name or service not known

Database connection failure: could not translate host name “db” to address: Name or service not known

Database connection failure: could not translate host name “db” to address: Name or service not known