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, yum or zypper.

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 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, 5.6. 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 (e.g., wheezy).

If you don’t 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://galeracluster.com/wsrep_8.0.19-26.3-rc/galera-4/ubuntu bionic main
deb https://galeracluster.com/wsrep_8.0.19-26.3-rc/mysql-wsrep-8.0/ubuntu bionic 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. 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 (e.g., CentOS, Red Hat and Fedora), 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 (e.g., it might be 5.6). The DIST should be changed to the name of the Linux distribution you’re using on your sever (e.g., centos or fedora). The RELEASE should be replaced with the distribution’s release number. It might be 6 for CentOS, but 20 or 21 for Fedora. Last, the ARCH indicates the architecture of your hardware. This could be changed to x86_64 for 64-bit systems.

After you’ve created, modified, and saved this repository file, you’ll 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.

Enabling the zypper Repository

For servers with Linux distributions that use zypper for package management (e.g., openSUSE and SUSE Linux Enterprise Server), you can enable the Codership repository by importing the GPG key and then creating a galera.repo file in the local directory.

To import the GPG key, execute the following from the command-line on your server:

rpm --import "https://releases.galeracluster.com/GPG-KEY-galeracluster.com"


Next, you’ll need to use a simple text editor to create a repository file called, galera.repo in the local directory. The contents should look something like the following:

[galera]
name = Galera
baseurl = https://releases.galeracluster.com/galera-3/DIST/RELEASE/ARCH

[MySQL-wsrep]
name = MySQL-wsrep
baseurl = https://releases.galeracluster.com/mysql-wsrep-VERSION/DIST/RELEASE/ARCH


You’ll have to adjust these baseurl repository addresses. Replace where you see VERSION above with the version of MySQL-wsrep you want to install (e.g., it might be 5.6). Next, substitute DIST in both addresses with the Linux distribution name (e.g., opensuse or sles). Where it says RELEASE, enter instead the distribution release number. Last, change ARCH to the architecture of the server’s hardware. For example, you would enter x86_64 for 64-bit systems. When you’re finished these modifications, save the file.

You’ll now need to add the Codership repository to zypper by executing the following two lines from the command-line:

zypper addrepo galera.repo
zypper refresh


Once that’s all done, you’ll be able to install the packages from the Codership repository using zypper. This is covered in the next section.

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 and zypper repositories include Galera Arbitrator with the Galera Replication Plugin, but for Debian-based distributions using apt-get you’ll need to include add it to your installation instruction.

So, for Debian-based distributions using the apt-get package manager, execute the following from the command-line:

apt-get install galera-3 galera-arbitrator-3 mysql-wsrep-5.6


If you want to install version 4 of Galera Cluster, you would instead execute the following from the command-line:

apt-get install galera-4 galera-arbitrator-4 mysql-wsrep-8.0


On servers using the yum package manager (i.e., Red Hat, Fedora and CentOS distributions), you would instead execute this command:

yum install galera-3 mysql-wsrep-5.6


Please note that on CentOS 6 and 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.

If you want to install version 4 of Galera Cluster using yum, you would instead execute the following from the command-line:

yum install galera-4 and mysql-wsrep-8.0


If you’re using the zypper utility, which would be used with openSUSE and SUSE Linux Enterprise Server, you would execute the following from the command-line:

zypper install galera-3 mysql-wsrep-5.6


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’ll need to take to update your system to the new database server. For more information, see Migrating to Galera Cluster.

MySQL Shared Compatibility Libraries

When installing Galera Cluster for MySQL on CentOS, versions 6 and 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’ll have to upgrade, which can be done with the Codership repository using yum.

There are two versions available for this package. Which version you’ll need will depend on which version of the MySQL wsrep database server you want to install.

For CentOS 6, 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 5.5 or 5.6, depending on the version of MySQL you want to use. For CentOS 7, to install MySQL version 5.6, you would execute the following from the command-line:

yum upgrade mysql-wsrep-shared-5.6


For CentOS 7, to install MySQL version 5.5, you will also need to disable the 5.6 upgrade. To do this, enter the following from the command-line:

yum upgrade -y mysql-wsrep-shared-5.5 -x mysql-wsrep-shared-5.6


When yum finishes the upgrade, you can then install the MySQL wsrep database server and the Galera Replication Plugin as described above.