PostgreSQL: FATAL - Peer authentication failed for user (PG::ConnectionBad) - ruby-on-rails

Question

I am working with PostgreSQL and I have a user with password matching the one specified in database.yml
postgres=# select * from pg_user
;
usename | usesysid | usecreatedb | usesuper | usecatupd | userepl | passwd | valuntil | useconfig
------------+----------+-------------+----------+-----------+---------+----------+----------+-----------
goodsounds | 16386 | t | t | t | t | ******** | |
postgres | 10 | t | t | t | t | ******** | |
(2 rows)
But when I try creating a database by running the command
rails db:create
I get the error
FATAL: Peer authentication failed for user "goodsounds"
Here is my pg_hba.conf:
# Database administrative login by Unix domain socket
local all postgres peer
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all peer
# IPv4 local connections:
host all all 127.0.0.1/32 trust
# IPv6 local connections:
host all all ::1/128 trust
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local replication postgres peer
#host replication postgres 127.0.0.1/32 trust
#host replication postgres ::1/128 trust
Previously "trust" above was md5 but I changed to see if that would help.
Here is my database.yml:
# PostgreSQL. Versions 8.2 and up are supported.
#
# Install the pg driver:
# gem install pg
# On Mac OS X with macports:
# gem install pg -- --with-pg-config=/opt/local/lib/postgresql84/bin/pg_config
# On Windows:
# gem install pg
# Choose the win32 build.
# Install PostgreSQL and put its /bin directory on your path.
#
# Configure Using Gemfile
# gem 'pg'
#
development:
adapter: postgresql
encoding: unicode
database: goodsounds_development
pool: 5
username: goodsounds
password: test
# Connect on a TCP socket. Omitted by default since the client uses a
# domain socket that doesn't need configuration. Windows does not have
# domain sockets, so uncomment these lines.
host: localhost
port: 5432
# Schema search path. The server defaults to $user,public
#schema_search_path: myapp,sharedapp,public
# Minimum log levels, in increasing order:
# debug5, debug4, debug3, debug2, debug1,
# log, notice, warning, error, fatal, and panic
# The server defaults to notice.
#min_messages: warning
# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
adapter: postgresql
encoding: unicode
database: goodsounds_test
pool: 5
username: goodsounds
password: test
production:
adapter: postgresql
encoding: unicode
database: goodsounds_production
pool: 5
username: goodsounds
password: test

Answer 1

"Peer authentication" means that it's using a unix socket and expecting the connecting unix user to have the same unix username as the postgresql username.
Since your local unix username is funkdified and you're trying to connect as user goodsounds over a unix domain socket (local) connection where your pg_hba.conf specifies peer authentication, Pg correctly rejects your connection attempt.
This is the default behaviour for many installs when using unix sockets.
You can:
Connect via TCP/IP by specifying a hostname in your database connection settings;
edit pg_hba.conf to use md5 password authentication instead of peer authentication for unix sockets (local connection type) so Pg accepts password authentication; or
Connect with a PostgreSQL username the same as your unix username and create the user in PostgreSQL if it doesn't exist yet.
See the docs for pg_hba.conf and the rest of the client authentication chapter of the documentation.
Note that changes to pg_hba.conf do not take effect immediately, you must restart or at least reload PostgreSQL to get it to reread pg_hba.conf.
Oh, also, if you have multiple PostgreSQL versions installed you might have a libpq from one version and a server from another. In this case make sure the location for the unix socket that libpq connects to by default is the same as the server's unix_socket_directories or override it with (e.g.) host=/tmp in your connection string.

Answer 2

I was facing same problem on Ubuntu machine so I removed this error by following some steps.
Switch to postgres user
$ sudo su - postgres
it will ask for password and by default password is postgres
After switch the user to postgres, open psql console
$ psql
so check the version of postgres if multiple versions are available
psql=# select VERSION();
PostgreSQL 9.1.13 on x86_64-unk.... # so version is 9.1
Now Open postgres user
vim /etc/postgresql/9.1/main/pg_hba.conf
9.1 is version return form upper command
and replace
local all postgres peer
to
local all postgres md5
Restart the service
sudo service postgresql restart
I write steps on my blog also
http://tarungarg402.blogspot.in/2014/10/set-up-postgresql-on-ubuntu.html

Answer 3

If "peer authentication" does not work, try md5 authenticaion.
To specify host try something like this:
psql -d <dbname> -U <username> -h <hostname>
or this:
psql -d <dbname> -U <username> -h <hostname> -W

Answer 4

edit /etc/postgresql/9.3/main/pg_hba.conf
# "local" is for Unix domain socket connections only
local all all peer
change to below line and it works for me
# "local" is for Unix domain socket connections only
local all all md5

Answer 5

Here's how I solved it;
Run the command below to confirm your PostgreSQL version.
psql --version
Navigate to the PostgreSQL configuration directory on your server, which is in /etc/postgresql/10/main. Take note that 10 is the version of my PostgreSQL installation on my server. Your version might be 9.5, 11 or 12 or any other version.
cd ~
cd /etc/postgresql/10/main
Once you navigate into the /etc/postgresql/10/main directory, open the file pg_hba.conf using the command below. This file controls: which hosts are allowed to connect, how clients are authenticated, which PostgreSQL user names they can use, which databases they can access:
sudo nano pg_hba.conf
Replace the following line below:
# Database administrative login by Unix domain socket
local all postgres peer
with the line below:
# Database administrative login by Unix domain socket
local all postgres md5
Also, replace the following line below:
# "local" is for Unix domain socket connections only
local all all peer
with the line below:
# "local" is for Unix domain socket connections only
local all all md5
Additionally, we may want to allow inbound connections to the PostgreSQL database in production (to allow host connections from all databases, all users, all addresses using the md5 method).
To achieve this, add the line below at the end of the file, and then save the file:
# remote connections
host all all all md5
Still within the /etc/postgresql/10/main directory, open and edit the file postgresql.conf using the command below:
sudo nano postgresql.conf
Replace the line # listen_address='127.0.0.1' or the line listen_address='127.0.0.1' or the line # listen_address='localhost' or the line listen_address='localhost' with the line below, in order to allow PostgreSQL database to listen to connections from all addresses:
listen_addresses = '*'
Save the file, and navigate to the root directory of your server:
cd ~
Restart or reload the PostgreSQL server using the command below:
sudo systemctl restart postgresql # To restart
sudo systemctl reload postgresql # To reload