Question

Fail to test Galera Cluster with MySQL 5.6 on CentOS 7.2

  • Posted February 22, 2022

I’m testing the Galera cluster.

The environment is Centos 7.2. DB is MySQL 5.6.

The success message was confirmed using the following instructions.

/etc/init.d/mysql start --wsrep-new-cluster

Starting MySQL… SUCCESS!

But if you check the cluster size, it says 0.

mysql -uroot -p -e “SHOW STATUS LIKE ‘wsrep_cluster_size’”

Enter password: ±-------------------±------+ | Variable_name | Value | ±-------------------±------+ | wsrep_cluster_size | 0 | ±-------------------±------+

The cnf file of the initial node I set is as follows.

/etc/my.cnf.d/galera.cnf


[mysqld] binlog_format=ROW default-storage-engine=innodb innodb_autoinc_lock_mode=2 bind-address=0.0.0.0

Galera Provider Configuration

wsrep_on=ON wsrep_provider=/usr/lib64/galera-3/libgalera_smm.so

Galera Cluster Configuration

wsrep_cluster_name=“test_cluster” wsrep_cluster_address=“gcomm://”

Galera Synchronization Configuration

wsrep_sst_method=rsync

Galera Node Configuration

wsrep_node_address=“my node_1 ip” wsrep_node_name=“galera1”


I turned off both firewall and selinux.

Please tell me the solution.

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Hello,

For MySQL and CentOS 7, I could suggest following the steps from this tutorial here:

https://bobbyiliev.com/blog/galera-cluster-mariadb-10-1-on-centos-7-server

However, as a side note, keep in mind that both MySQL 5.6 and CentOS 7 are both EOL, meaning that they are no longer officially supported and no security updates will be released. So if you are setting this up for a production system, I would advise going for a tech stack that is still supported.

For example, you could set up a Galera Cluster with MariaDB on Ubuntu 20.04 Server as described here:

https://www.digitalocean.com/community/tutorials/how-to-configure-a-galera-cluster-with-mariadb-on-ubuntu-18-04-servers

Best,

Bobby

Hi @

It’s hard to troubleshoot it like that, quick searches have showed me similar issues which have been resolved like:

  • Check if /etc/mysql/my.cnf is missing the line !includedir /etc/mysql/mysql.conf.d/
  • Make sure both servers have the exact same version of MySQL.