Technical Tools

Recently, I was setting up MySQL Galera cluster on redhat 7.4. I installed MySQL 5.7 and Galera cluster on the system according to the instructions provided in galera support page ( Galera Cluster setup ). I have made a blog post for installation and setup here . But when I started the mysql, I was not able to login as I did not setup any password for mysql root account. When I tried logging in without password, I got access denied. After looking for the answers on internet, I found out that MySQL creates a temporary password and write it in log files. It is clrearly mentioned in mysql documentation here . All I needed to do to find this password is to run the following command.      grep 'temporary password' /var/log/mysqld.log Problem solved !

Galera Cluster is a master-master replication, this means it keeps same data on all the nodes. For this purpose it transfers data continuously between nodes (IST or SST). There are 2 methods with which you can transfer the data. Using Percona XtraBackup or rsync. We are going to use rsync.                         yum install rsync We need to setup SELinux in permissive mode for required ports so that nodes can communicate. For this purpose we are going to use semanage . We can install this by given command.        yum install policycoreutils-python Also you firewall should not stop communication between the nodes, you can use telnet utility to check if nodes can communicate with each other on specific ports. If its not already installed, you can install it.               ...