Fail to test Galera Cluster with MySQL 5.6 on CentOS 7.2

Question

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.

Bobby Iliev · Answer

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

KFSys · Answer

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.

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