A common question we get is: can I add a node to my Galera Cluster without restarting the entire cluster? The simple answer is YES.

A lot worry about the fact that you do list servers that are part of the cluster within your my.cnf, and this file is not reloadable in a dynamic fashion. Fret not, though, because as long as your my.cnf has one active cluster member (the DONOR), you can have it be the JOINER.

If for example, you have 3 nodes: galera1: 159.223.105.21 galera2: 137.184.78.182 galera3: 137.184.65.171

The my.cnf line for wsrep_address should read as follows:

wsrep_cluster_address="gcomm://159.223.105.21,137.184.78.182,137.184.65.171"

It is then trivial for you to have your fourth server (say, galera4: 161.35.120.111), have a my.cnf that reads as follows:

wsrep_cluster_address="gcomm://159.223.105.21,137.184.78.182,137.184.65.171,161.35.120.111"

Now, …

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 5.7, consisting of MySQL-wsrep 5.7.41 (release notes, download) and MySQL-wsrep 8.0.32 (release notes, download). This release incorporates all changes to MySQL 5.7.41 and MySQL 8.0.32 respectively, adding a …

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 5.7, consisting of MySQL-wsrep 5.7.40 (release notes, download) and MySQL-wsrep 8.0.31 (release notes, download) with Galera replication library 4.14 (release notes, download) implementing wsrep API version 26. …

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We recently covered Upgrading your Galera Cluster from MySQL 5.7 to MySQL 8.0. We’ve also had questions on how the upgrade path from our usual Galera Cluster “community” edition to the Galera Cluster Enterprise Edition (EE), which includes many new features, like XA transaction support, arm64 support or GCache encryption.

First off, let’s start by installing a Galera Cluster on CentOS 7. The reason we have picked this distribution? Let’s edit the /etc/yum.repos.d/galera.repo and add:

[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 = …

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 8.0, consisting of MySQL-wsrep 8.0.30 (release notes, download) with Galera replication library 4.13 (release notes, download) implementing wsrep API version 26. This release incorporates all changes to MySQL 8.0.30, adding a synchronous option for your MySQL High Availability solutions.

For the Galera replication library 4.13, we now complete the I/O for the client handshake before starting an asynchronous read to fix …

Recently we had a question on getting your Galera Cluster upgraded from MySQL 5.7 to MySQL 8.0. While we have plenty of extensive documentation on Upgrading Galera Cluster, this blog covers the Linux example for a rolling major upgrade (the procedure is documented, but this is more extensive). So we will describe going from MySQL 5.7.23 to MySQL 8.0.28 on one node. We did this on CentOS 7.

Firstly, let’s start by disabling SELinux by executing setenforce 0.

We need to install the appropriate MySQL 5.7 binaries, so we can grab them from releases.galeracluster.com. Since we have decided on MySQL 5.7.23, we should get the packages from …

Continuing on from Setting up Galera Load Balancer (GLB), wouldn’t it be nice to ensure that Galera Load Balancer (GLB) handles failover, seamlessly?

Router:
------------------------------------------------------
        Address       :   weight   usage    map  conns
188.166.179.177:3306  :    1.000   0.500    N/A      1
  165.22.50.152:3306  :    1.000   0.500    N/A      1
   165.22.49.92:3306  :    1.000   0.000    N/A      0
------------------------------------------------------
Destinations: 3, total connections: 2 of 493 max

Pool: connections per thread:     1     1     0     0     0     0

Here is an example of a Galera Load Balancer (GLB) handling 3 backend MySQL servers, and it currently has 2 connections, evenly distributed between 2 hosts.

We can verify this by doing: select @@hostname; which shows:

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 5.7, consisting of MySQL-wsrep 5.7.38 (release notes, download). This release incorporates all changes to MySQL 5.7.39, adding a synchronous option for your MySQL High Availability solutions.

We have backported the InnoDB wsrep applier lock wait timeout from 8.0 which introduces the variable innodb-wsrep-applier-lock-wait-timeout to improve the reliability in resolving …

Galera Load Balancer (GLB) is a scalable and performant, yet easy to use TCP/IP connection balancing proxy. It is the oldest, yet actively maintained load balancer in the MySQL ecosystem, with a wide array of customers using it in production.

Firstly, please request for binaries via contacting sales@galeracluster.com. Once you have access to the package repository, you’ll have access to RPMs. Installing the RPMs are straightforward, and you can also add it to your Yum repository. This blog presumes you already have access to the binaries.

You can start it up, really simply:

glbd --threads 6 127.0.0.1:3306 188.166.179.177:3306 165.22.50.152:3306 165.22.49.92:3306 …