MySQL Can't connect to local MySQL server

A connection error indicating the MySQL client cannot establish a socket connection to the MySQL server process. It typically occurs when connecting to 'localhost'.

Common Causes

The MySQL server service (mysqld) is not running.
Incorrect socket file path or permissions for the MySQL socket.
Using 'localhost' which forces a socket connection, but the server is configured for TCP/IP only.
Firewall rules blocking the MySQL port (usually 3306) when connecting via TCP/IP.
Incorrect 'bind-address' configuration in the MySQL server's my.cnf file.

How to Fix

1 Check and Start MySQL Service

Ensure the MySQL server daemon is running on the host.

BASH

 $ # On systemd systems (Ubuntu, CentOS 7+)
sudo systemctl status mysql
# If stopped, start it
sudo systemctl start mysql

# On older SysVinit systems
sudo service mysql status
sudo service mysql start

2 Verify Socket Connection

Check the location of the MySQL socket file and ensure your client is looking in the correct place.

BASH

 $ # Find the socket file path from MySQL config
sudo grep 'socket' /etc/mysql/my.cnf /etc/my.cnf 2>/dev/null

# Common default path
ls -la /var/run/mysqld/mysqld.sock

# Connect using the explicit socket path
mysql -u root --socket=/var/run/mysqld/mysqld.sock -p

3 Force TCP/IP Connection

Use '127.0.0.1' instead of 'localhost' to bypass socket and use the network loopback interface.

BASH

$ mysql -u root -h 127.0.0.1 -p

4 Check Server Bind Configuration

Ensure the MySQL server is configured to accept connections on the expected interface.

BASH

 $ # Check the bind-address in MySQL config
sudo grep 'bind-address' /etc/mysql/my.cnf /etc/mysql/mysql.conf.d/mysqld.cnf 2>/dev/null

# Common values:
# bind-address = 127.0.0.1  (localhost only)
# bind-address = 0.0.0.0    (all interfaces)
# Comment it out or set to 127.0.0.1 for local connections, then restart MySQL.