Connection and privileges needed¶
Percona XtraBackup needs to be able to connect to the database server and perform operations on the server and the datadir when creating a backup, when preparing in some scenarios and when restoring it. In order to do so, there are privileges and permission requirements on its execution that must be fulfilled.
Privilege refers to the operations that a system user is permitted to do in the database server. They are set at the database server and only apply to users in the database server.
Permissions are those which permits a user to perform operations on the system, like reading, writing or executing on a certain directory or start/stop a system service. They are set at a system level and only apply to system users.
When xtrabackup is used, there are two actors involved: the user invoking the program - a system user - and the user performing action in the database server - a database user. Note that these are different users in different places, even though they may have the same username.
All the invocations of xtrabackup in this documentation assume that the system user has the appropriate permissions, and you are providing the relevant options for connecting the database server - besides the options for the action to be performed - and the database user has adequate privileges.
Connect to the server¶
The database user used to connect to the server and its password are specified
$ xtrabackup --user=DVADER --password=14MY0URF4TH3R --backup \ --target-dir=/data/bkps/
If you don’t use the
--user option, Percona XtraBackup will assume
the database user whose name is the system user executing it.
Other connection options¶
According to your system, you may need to specify one or more of the following options to connect to the server:
|-port||Use this port when connecting to the database with TCP/IP|
|-socket||Use this socket when connecting to the local database.|
|-host||Use this host when connecting to the database server with TCP/IP|
These options are passed to the mysql child process without
mysql --help for details.
In case of multiple server instances, the correct connection parameters (port, socket, host) must be specified in order for xtrabackup to talk to the correct server.
Once connected to the server, in order to perform a backup you need
EXECUTE permissions at a filesystem level in the server’s datadir.
The database user needs the following privileges to back up tables or databases:
LOCK TABLES(unless the
--no-lockoption is specified) in order to run
FLUSH TABLES WITH READ LOCKand
FLUSH ENGINE LOGSprior to start copying the files, and requires this privilege when Backup Locks are used
BACKUP_ADMINprivilege is needed to query the performance_schema.log_status table, and run
LOCK INSTANCE FOR BACKUP,
LOCK BINLOG FOR BACKUP, or
LOCK TABLES FOR BACKUP.
REPLICATION CLIENTin order to obtain the binary log position,
CREATE TABLESPACEin order to import tables (see Restoring Individual Tables),
PROCESSin order to run
SHOW ENGINE INNODB STATUS(which is mandatory), and optionally to see all threads which are running on the server (see FLUSH TABLES WITH READ LOCK option),
SUPERin order to start/stop the replication threads in a replication environment, use XtraDB Changed Page Tracking for Incremental Backups and for handling FLUSH TABLES WITH READ LOCK,
CREATEprivilege in order to create the PERCONA_SCHEMA.xtrabackup_history database and table,
ALTERprivilege in order to upgrade the PERCONA_SCHEMA.xtrabackup_history database and table,
INSERTprivilege in order to add history records to the PERCONA_SCHEMA.xtrabackup_history table,
SELECTprivilege in order to use
--incremental-history-uuidin order for the feature to look up the
innodb_to_lsnvalues in the PERCONA_SCHEMA.xtrabackup_history table.
SELECTprivilege on the keyring_component_status table to view the attributes and status of the installed keyring component when in use.
SELECTprivilege on the replication_group_members table to validate if the instance is part of group replication cluster.
A SQL example of creating a database user with the minimum privileges required to take full backups would be:
mysql> CREATE USER 'bkpuser'@'localhost' IDENTIFIED BY 's3cr%T'; mysql> GRANT BACKUP_ADMIN, PROCESS, RELOAD, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'bkpuser'@'localhost'; mysql> GRANT SELECT ON performance_schema.log_status TO 'bkpuser'@'localhost'; mysql> GRANT SELECT ON performance_schema.keyring_component_status TO bkpuser@'localhost'; mysql> GRANT SELECT ON performance_schema.replication_group_members TO bkpuser@'localhost'; mysql> FLUSH PRIVILEGES;
Query the privileges¶
To query the privileges that your database user has been granted at the console of the server execute:
mysql> SHOW GRANTS;
or for a particular user with:
mysql> SHOW GRANTS FOR 'db-user'@'host';
It will display the privileges using the same format as for the GRANT statement.
Note that privileges may vary across versions of the server. To list the exact list of privileges that your server support (and a brief description of them) execute:
mysql> SHOW PRIVILEGES;