Uly.me

cloud engineer

mysql

MySQL Restore to another DB

In order to restore a MySQL database to another database, use routines and triggers.

mysqldump -p user -p --routines --triggers db1 > db1.sql

To restore to another database, just use the normal command.

mysql -u user -p db2 < db1.sql

MySQL SSL Connection

The standard way to connect to MySQL is:

mysql -h hostname -u user -p

Here’s how to connect to MySQL with SSL encryption.

mysql -h hostname -u user -p \
--ssl-ca=server-ca.pem \
--ssl-cert=client-cert.pem \
--ssl-key=client-key.pem

Generate the SSL keys from the MySQL server. Download it to the client.

MySQL Restore

Here’s how to restore a MySQL database from mysqldump.

mysql -u user -p
mysql> drop database databasename;
mysql> quit;
Bye
mysql -u user -p databasename < filename.sql

Drop database first, then import the SQL file.

MySQL Backup To S3 Bucket

Here’s my MySQL backup script to the S3 Bucket.

Just a couple of things about the script. It’s using …

  1. AWS CLI
  2. Mysqldump

They must be setup and configured to work properly.

#!/bin/bash
cd /root/database
TIMESTAMP=$(date +%Y-%m-%d)
S3FILE="s3://bucketname/sqlbackup/backup-$TIMESTAMP.sql"
/usr/bin/mysqldump dbname > dbname.sql
/usr/local/bin/aws s3 cp dbname.sql $S3FILE
sleep 3s
rm dbname.sql

Finally, set the S3 bucket with a 7 day retention. Backups older than 7 days are automatically deleted.

Recover MySQL Root Password

How to recover a MySQL root password without a password.

  1. Stop MySQL.
  2. Start MySQL Safe Mode.
  3. Login to MySQL as root without password.
  4. Change root password.

# Stop MySQL.
service mysql stop
# MySQL Safe Mode.
mysqld_safe --skip-grant-tables &
# Login to MySQL without password. Set new password.
mysql -u root -p
use mysql;
# For MySQL 5.6 or lower
UPDATE mysql.user SET Password=PASSWORD('newpassword') WHERE User='root';
# For MySQL 5.7 or higher
SET PASSWORD FOR 'root'@'localhost' = PASSWORD("newpassword");
FLUSH PRIVILEGES;
exit;
# Kill mysqld
killall mysqld
# Restart MySQL
service mysql start

I ran into issues running MySQL Safe mode. I got a “UNIX socket file don’t exists” error. Here’s the fix.

mkdir -p /var/run/mysqld
chown mysql:mysql /var/run/mysqld

Run SQL in Bash

Here’s an example on how to run MySQL commands from Bash.

mysql dbname -e "UPDATE wp_options SET option_value='http://domain.com' WHERE option_name='home'";
mysql dbname -e "UPDATE wp_options SET option_value='http://domain.com' WHERE option_name='siteurl'";

The example updates WordPress’ home and siteurl. Script contains no password. It’s using .my.cnf config file.