How can I export the privileges from MySQL and then import to a new server?

Solution 1:

Do not mess with the mysql db. There is a lot more going on there than just the users table. Your best bet is the "SHOW GRANTS FOR" command. I have a lot of CLI maintenance aliases and functions in my .bashrc (actually my .bash_aliases that I source in my .bashrc). This function:

mygrants()
{
  mysql -B -N $@ -e "SELECT DISTINCT CONCAT(
    'SHOW GRANTS FOR \'', user, '\'@\'', host, '\';'
    ) AS query FROM mysql.user" | \
  mysql $@ | \
  sed 's/\(GRANT .*\)/\1;/;s/^\(Grants for .*\)/## \1 ##/;/##/{x;p;x;}'
}

The first mysql command uses SQL to generate valid SQL which is piped to the second mysql command. The output is then piped through sed to add pretty comments.

The $@ in the command will allow you to call it as: mygrants --host=prod-db1 --user=admin --password=secret

You can use your full unix tool kit on this like so:

mygrants --host=prod-db1 --user=admin --password=secret | grep rails_admin | mysql --host=staging-db1 --user=admin --password=secret

That is THE right way to move users. Your MySQL ACL is modified with pure SQL.

Solution 2:

There are two methods for extracting SQL Grants from a MySQL Instance

METHOD #1

You can use pt-show-grants from Percona Toolkit

MYSQL_CONN="-uroot -ppassword"
pt-show-grants ${MYSQL_CONN} > MySQLUserGrants.sql

METHOD #2

You can emulate pt-show-grants with the following

MYSQL_CONN="-uroot -ppassword"
mysql ${MYSQL_CONN} --skip-column-names -A -e"SELECT CONCAT('SHOW GRANTS FOR ''',user,'''@''',host,''';') FROM mysql.user WHERE user<>''" | mysql ${MYSQL_CONN} --skip-column-names -A | sed 's/$/;/g' > MySQLUserGrants.sql

Either method will produce a pure SQL dump of the MySQL grants. All there is left to do is to execute the script on a new server:

mysql -uroot -p -A < MySQLUserGrants.sql

Give it a Try !!!

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Solution 3:

Richard Bronosky's answer was extremely useful for me. Many thanks!!!

Here is a small variation which was useful for me. It is helpful for transfering users e.g. between two Ubuntu installations running phpmyadmin. Just dump privileges for all users apart from root, phpmyadmin and debian-sys-maint. The code is then

mygrants()
{
mysql -B -N $@ -e "SELECT DISTINCT CONCAT(
'SHOW GRANTS FOR ''', user, '''@''', host, ''';'
) AS query FROM mysql.user WHERE user NOT IN ('root','phpmyadmin','debian-sys-maint')"  | \
mysql $@ | \
sed 's/\(GRANT .*\)/\1;/;s/^\(Grants for .*\)/## \1 ##/;/##/{x;p;x;}'
}

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Solution 4:

Or, utilize percona-toolkit (former maatkit) and use pt-show-grants (or mk-show-grants) for that purpose. No need for cumbersome scripts and/or stored procedures.

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Solution 5:

You can mysqldump the 'mysql' database and import to the new one; a flush_privileges or restart will be required and you'll definitely want to back up the existing mysq db first.

To avoid removing your existing privileges, make sure to append rather than replace rows in the privilege tables (db, columns_priv, host, func, etc.).