Upgrade MariaDB Community Server from 10.4.X to 10.4.Y on CentOS 7

These instructions detail a minor release upgrade with MariaDB Community Server 10.4 on CentOS Linux 7.

A minor release upgrade is a change from an earlier release of MariaDB Community Server 10.4 to a later release in the same release series.

For example, it would be a minor release upgrade to upgrade from MariaDB Community Server to MariaDB Community Server .

Data Backup

Occasionally, issues can be encountered during upgrades. These issues can even potentially corrupt the database's data files, preventing you from easily reverting to the old installation. Therefore, it is generally best to perform a backup prior to upgrading. If an issue is encountered during the upgrade, you can use the backup to restore your MariaDB Server database to the old version. If the upgrade finishes without issue, then the backup can be deleted.

The instructions below show how to perform a backup using MariaDB Backup. For more information about backing up and restoring the database, please see the Recovery Guide.

Take a full backup:

$ sudo mariadb-backup --backup \
      --user=mariabackup_user \
      --password=mariabackup_passwd \
      --target-dir=/data/backup/preupgrade_backup

Confirm successful completion of the backup operation.

The backup must be prepared:

$ sudo mariadb-backup --prepare \
      --target-dir=/data/backup/preupgrade_backup

Confirm successful completion of the prepare operation.

Backups should be tested before they are trusted.

Stop the MariaDB Server Process

Before the new version can be installed, we first need to stop the current MariaDB Server process.

Stop the server process using the systemctl command:
```
$ sudo systemctl stop mariadb
```

Install the New Version

MariaDB Corporation provides a YUM package repository for CentOS Linux 7.

Install via YUM (RHEL/CentOS)

Configure the YUM package repository.

To configure YUM package repositories:

$ sudo yum install wget

$ wget https://downloads.mariadb.com/MariaDB/mariadb_repo_setup

$ echo "b7519209546e1656e5514c04b4dcffdd9b4123201bcd1875a361ad79eb943bbe mariadb_repo_setup" \
    | sha256sum -c -

$ chmod +x mariadb_repo_setup

$ sudo ./mariadb_repo_setup \
   --mariadb-server-version="mariadb-10.4"

Update MariaDB Community Server and package dependencies:
```
$ sudo yum update "MariaDB-*" "galera*"
```

Configuration

For platforms that use YUM or ZYpp as a package manager:

MariaDB Community Server's packages bundle several configuration files:

/etc/my.cnf
/etc/my.cnf.d/client.cnf
/etc/my.cnf.d/mysql-clients.cnf
/etc/my.cnf.d/server.cnf

If your version of any of these configuration files contained any custom edits, then the package manager may save your edited version with the .rpmsave extension during the upgrade process. If you want to continue using your version with the custom edits, then you may need to move it back. For example, to move server.cnf back in place:

$ sudo mv /etc/my.cnf.d/server.cnf /etc/my.cnf.d/server.cnf.original
$ sudo mv /etc/my.cnf.d/server.cnf.rpmsave /etc/my.cnf.d/server.cnf

Starting the Server

MariaDB Community Server includes configuration to start, stop, restart, enable/disable on boot, and check the status of the Server using the operating system default process management system.

CentOS Linux 7 uses systemd. You can manage the Server process using the systemctl command:

Operation	Command
Start	`sudo systemctl start mariadb`
Stop	`sudo systemctl stop mariadb`
Restart	`sudo systemctl restart mariadb`
Enable during startup	`sudo systemctl enable mariadb`
Disable during startup	`sudo systemctl disable mariadb`
Status	`sudo systemctl status mariadb`

Upgrading the Data Directory

MariaDB Community Server 10.4 ships with the mariadb-upgrade utility which can be used to identify and correct compatibility issues in the new version. After you upgrade your Server and start the server process, run this utility to upgrade the data directory:

$ sudo mariadb-upgrade

Testing

When MariaDB Community Server is up and running on your system, you should test that it is working and there weren't any issues during startup.

Connect to the server using MariaDB Client using the root@localhost user account:

$ sudo mariadb
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 9
Server version: 10.4.17-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

The version of the server can be verified by checking the client's initial output.

You can also verify the server version by checking the value of the version system variable with the SHOW GLOBAL STATUS statement:

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE 'version';
+---------------+------------------------------+
| Variable_name | Value                        |
+---------------+------------------------------+
| version       | 10.4.17-MariaDB |
+---------------+------------------------------+
1 row in set (0.001 sec)

You can also verify the server version by calling the VERSION() function:

MariaDB [(none)]> SELECT VERSION();
+------------------------------+
| VERSION()                    |
+------------------------------+
| 10.4.17-MariaDB |
+------------------------------+
1 row in set (0.000 sec)