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Galera Cluster for MySQL—Binary Installation¶
Galera Cluster for MySQL may be installed on Linux servers using binary packages. These files can be downloaded directly from the Codership repository, or by way of a package manager: apt-get or yum.
Enabling the Codership Repository
To install Galera Cluster for MySQL with a package manager, you first will have to enable the Codership repository on the server. There are a few ways to do this, depending on which Linux distribution and package manager you use. The sections below provide details on how to use each of the three main supported package managers to install Galera Cluster for MySQL.
Enabling the apt Repository
For Debian and Debian-based Linux distributions, the procedure for adding a repository requires that you first install the Software Properties. The package names vary depending on the distribution. For Debian, at the command-line, execute the following command:
apt-get install python-software-properties
For Ubuntu or a distribution derived from Ubuntu, you would execute instead the following:
apt-get install software-properties-common
If your server uses a different Debian-based distribution, and neither of these commands work on your system, try consulting your distribution’s package listings for the appropriate package name.
Once you have the Software Properties installed, you can then enable the Codership repository for your system. Start by adding the GnuPG key for the repository. This is done by executing the following from the command-line:
apt-key adv --keyserver keyserver.ubuntu.com --recv 8DA84635
Note
For packages before MySQL 5.7.44 and 8.0.35, the signing key is BC19DDBA. Next, add the Codership repository to your sources list. Using a simple text editor, create file called, galera.list in the /etc/apt/sources.list.d/ directory. Add these lines to that file, with the necessary adjustments for the version used:
# Codership Repository (Galera Cluster for MySQL)
deb https://releases.galeracluster.com/mysql-wsrep-VERSION/DIST RELEASE main
deb https://releases.galeracluster.com/galera-3/DIST RELEASE main
In the example above, you would change the repository addresses. The VERSION should be set to MySQL-wsrep version you want to install. For example, it might be something like, 8.4. The DIST should be replaced with the name of the Linux distribution on the server. This could be ubuntu. Last, replace RELEASE with the distribution release (for example, wheezy).
If you do not know which release you have installed on your server, you can generally find this using the following command:
lsb_release -a
Version 4 of Galera was recently released. If you’d like to install it, the configuration lines in galera.list should read similar to the following:
# Codership Repository (Galera Cluster for MySQL)
deb https://releases.galeracluster.com/galera-4/ubuntu focal main
deb https://releases.galeracluster.com/mysql-wsrep-8.0/ubuntu focal main
Again, you may have to adust the version and release numbers, depending on which you want to install. Please note that this will require at least version 18.04 of Ubuntu.
To be assured the proper version is installed and updated, set which repository you prefer to the Codership repository (this is not only recommended, it is required). To do this, using a text editor, create a file called, galera.pref in the /etc/apt/preferences.d/ directory. The contents should look like the following:
# Prefer Codership repository
Package: *
Pin: origin releases.galeracluster.com
Pin-Priority: 1001
This is needed to make sure the patched versions are preferred. This might be important, for instance, if a third-party program requires libmysqlclient20 and the OS-version for the library is newer.
Finally, you should update the local cache of the repository. Do this by entering the following from the command-line:
apt-get update
Once you’ve done all of these tasks, the packages in the Codership repository will be available for installation. For information on installing them using apt-get, skip ahead on this page to the section entitled, Installing Galera Cluster for MySQL.
Enabling the yum Repository
For rpm-based distributions of Linux (for example, CentOS and Red Hat Enterprise Linux), you will need to enable the Codership repository. Using a simple text editor, create a file called, galera.repo in the /etc/yum.repos.d/ directory. The contents of that file should look something like the following:
[galera]
name = Galera
baseurl = https://releases.galeracluster.com/galera-3/DIST/RELEASE/ARCH
gpgkey = https://releases.galeracluster.com/GPG-KEY-galeracluster.com
gpgcheck = 1
[mysql-wsrep]
name = MySQL-wsrep
baseurl = https://releases.galeracluster.com/mysql-wsrep-VERSION/DIST/RELEASE/ARCH
gpgkey = https://releases.galeracluster.com/GPG-KEY-galeracluster.com
gpgcheck = 1
In this sample repository configuration file, you would change the repository addresses for the baseurl. The VERSION should be set to the whichever MySQL-wsrep version you want (for example, it might be 5.7). The DIST should be changed to the name of the Linux distribution you are using on your sever (for example, centos). The RELEASE should be replaced with the distribution’s release number. It might be 7 or 8 for CentOS and Red Hat Enterprise Linux. Last, the ARCH indicates the architecture of your hardware. This could be changed to x86_64 for 64-bit systems.
Here is a sample repository configuration file for CentOS 7 and Galera Cluster with MySQL 8.
[galera4]
name = Galera
baseurl = https://releases.galeracluster.com/galera-4/centos/7/x86_64
gpgkey = https://releases.galeracluster.com/GPG-KEY-galeracluster.com
gpgcheck = 1
[mysql-wsrep8]
name = MySQL-wsrep
baseurl = https://releases.galeracluster.com/mysql-wsrep-8.0/centos/7/x86_64
gpgkey = https://releases.galeracluster.com/GPG-KEY-galeracluster.com
gpgcheck = 1
After you’ve created, modified, and saved this repository file, you will be able to install the packages from the Codership repository using yum. For an explanation on installing, skip ahead on this page to the section entitled, Installing Galera Cluster for MySQL.
Installing Galera Cluster for MySQL
There are two packages involved in the installation of Galera Cluster for MySQL: the MySQL database server, but one that has been built to include the wsrep API; and the Galera Replication Plugin. The yum repositories include Galera Arbitrator with the Galera Replication Plugin, but for Debian-based distributions using apt-get you will need to include add it to your installation instruction.
Note
If SELinux (Security-Enhanced Linux) is enabled on the servers, disable it. See Disabling SELinux for mysqld. Also, if AppArmor is enabled on the servers, disable it. See Disabling AppArmor. However, this is optional, and there are methods to enable the context files.
So, for Debian-based distributions using the apt-get package manager, execute the following from the command-line:
For Galera Cluster 8.0:
apt-get install galera-4 galera-arbitrator-4 mysql-wsrep-8.0
For Galera Cluster 8.4:
apt-get install galera-4 galera-arbitrator-4 mysql-wsrep-8.4
On servers using the yum package manager (that is, Red Hat Enterprise Linux and CentOS distributions), you would instead execute this command:
yum install galera-4 mysql-wsrep-8.4
For mysql-wsrep-8.0:
yum install galera-4 mysql-wsrep-8.0
Note
On CentOS 7, this command may generate a transaction check error. For more information on that error and how to resolve it, see the section below on MySQL Shared Compatibility Libraries.
Please note that on Red Hat 8, you need to disable MySQL and MariaDB modules before installing Galera Cluster from a repository under https://releases.galeracluster.com/. In order to do this, execute the following from the command-line:
dnf module disable mysql mariadb
Once you’ve executed the line appropriate to your distribution and package manager, Galera Cluster for MySQL should be installed on your server. You will then have to repeat this process for each node in your cluster, including enabling the repository files mentioned earlier.
Incidentally, when deciding which packages from the Codership repository to install, the package manager may elect to install a newer major verion of Galera Cluster, newer than the one you intended to install. Before confirming the installation of packages, make sure that the package manager is planning to install the Galera Cluster version you want.
If you installed Galera Cluster for MySQL over an existing stand-alone instance of MySQL, there are some additional steps that you will need to take to update your system to the new database server. For more information, see Migrating to Galera Cluster.
When installing Galera Cluster for MySQL on CentOS 7, you may encounter a transaction check-error that blocks the installation. The error message may look something like this:
Transaction Check Error:
file /usr/share/mysql/czech/errmsg.sys from install
mysql-wsrep-server-5.6-5.6.23-25.10.e16.x86_64 conflicts
with file from package mysql-libs-5.1.73-.3.e16_5.x86_64
This relates to a dependency problem between the version of the MySQL shared compatibility libraries that CentOS uses, and the one that Galera Cluster requires. To resolve this, you will have to upgrade, which can be done with the Codership repository using yum.
There are two versions available for this package. Which version you will need will depend on which version of the MySQL wsrep database server you want to install.
For CentOS, you would enter something like the following from the command-line:
yum upgrade -y mysql-wsrep-libs-compat-VERSION
You would, of course, replace VERSION here with 5.7 or 8.0, depending on the version of MySQL you want to use. For CentOS 7, to install MySQL version 5.7, you would execute the following from the command-line:
yum upgrade mysql-wsrep-shared-5.7
For CentOS 7, to install MySQL version 5.7, you will also need to disable the 5.7 upgrade. To do this, enter the following from the command-line:
yum upgrade -y mysql-wsrep-shared-5.7 -x mysql-wsrep-shared-5.7
When yum finishes the upgrade, you can then install the MySQL wsrep database server and the Galera Replication Plugin as described above.
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