- A Cloud Guru
Implement a Primary-Replica Cluster Using MariaDB Galera Cluster and Galera Load Balancer
In this activity, you are working as a DBA and have been tasked with configuring a MariaDB Galera Cluster in a Primary-Replica configuration. The cluster is already up and running, but you will need to install the Galera Load Balancer and configure it appropriately.
Table of Contents
Set the root Database User's Password and Create a Database User Account
The database nodes are running and connected to the cluster, however the
rootuser's password has not been set. You must first set the
rootuser's password by running the
Now you can connect to the database as the
rootuser and create a user account:
mysql -u root -p
Once connected, you can use the following SQL to create a user named
remotewho is able to login remotely. Be sure to replace mypasswd with a password of your choice.
create user remote identified by 'mypasswd'; grant usage on *.* to 'remote'@'%' identified by 'mypasswd';
Install the Prerequisite Packages
sudo yum -y install git autoconf automake libtool gcc-c++ nmap-ncat
Build the Galera Load Balancer Binaries
git clone https://github.com/codership/glb cd glb ./bootstrap.sh ./configure make sudo make install
Configure and Start Galera Load Balancer
sudo cp /home/cloud_user/glb/files/mysql.sh /usr/local/bin/mysql-check.sh sudo cp /home/cloud_user/glb/files/glbd.sh /etc/init.d/glb
Create glbd configuration file:
sudo vi /etc/sysconfig/glbd
# Address to listen for client connections at. Mandatory parameter. # To bind to all interfaces only port should be specified. LISTEN_ADDR="10.0.1.100:13306" # Address for controlling connection. Mandatory part is port. # If not specified control socket will not be opened CONTROL_ADDR="127.0.0.1:4444" # Target servers for client connections, space separated. # Target specification: IP[:PORT[:WEIGHT]] (WEIGHT and PORT optional) # WEIGHT defaults to 1, PORT defaults to LISTEN_ADDR port. DEFAULT_TARGETS="10.0.1.100:3306:10 10.0.1.110:3306:1" # Other glbd options if any as they would appear on the command line. OTHER_OPTIONS="--single --watchdog exec:'/usr/local/bin/mysql-check.sh -uremote -pmypasswd'"
Start the service:
sudo service glb start sudo service glb status
Confirm Connections to Primary and Replica Nodes
Connect to the primary node via the load balancer:
mysql -h 10.0.1.100 -P 13306 -u remote -p
The connection is sent to the single server with the highest weight of those available, in this case
Connections to the replica can be made directly on port 3306:
mysql -h 10.0.1.110 -P 3306 -u remote -p
Promote Replica to Primary
A replica node can become the primary node by changing each of their weights:
service glb add 10.0.1.100:3306:1 service glb add 10.0.1.110:3306:10
Confirm connections are routed to
mysql -h 10.0.1.100 -P 13306 -u remote -p service glb status
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