PostgreSQL: su - Authentication failure in postgresql

Question

I have installed PostgreSQL 10.6, Postgres client and Pgadmin 4.

I just created a new Rails application and I used Postgresql as the database for the application, only for me to get a message saying

su: Authentication Failure

each time I try to login into the postgres account to create the development database for the rails application.

I have tried a couple of times to fix this issue, I have also attempted to solve by trying out several solutions that I found online, but all to no avail.

What should I do? I need some assistance.

Answer 1

To solve this simply follow the solution below

Change the password for a user

Login to the server where PostgreSQL is installed.

Next, switch to the root user:

sudo su -

Log in to psql using the postgres database login role, connecting to the postgres database:

psql postgres postgres

Issue the \password command to alter the password of the user:

\password my-user

Note: This will prompt you to enter a new password twice.

And then exit the psql prompt:

\q 

Afterwhich you can exit and then test the password using the command below to login to the postgres database:

psql -U my-user -W postgres

Change the password for the postgres user

If you do not know the password for the postgres user, run the psql command from the postgres user account:

sudo passwd postgres

Note: This will prompt you to enter a new password twice.

And then exit the psql prompt:

\q 

To test and confirm the password change or setup, run the psql command from the postgres user account:

su - postgres

Enter the new password that you just setup.

That's all

I hope this helps.