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[How-To] Configure HAProxy for MariaDB Galera Cluster Load Balancing

Purpose

Explain the process of configuring the cfg file on haproxy to load balance a MariaDB Galera cluster of 3 servers.

Prerequisites

List of prerequisites:

  • Root user or sudo user
  • MariaDB Galera Clustered Servers (Minimum 3)
  • HAProxy Server

Instructions

Step 1: Edit the HAProxy Config File

Use the following base config to either replace or edit the haproxy config on your servers to allow for load balancing of MariaDB Galera clustered servers:

global
    log /dev/log    local0
    log /dev/log    local1 notice
    chroot /var/lib/haproxy
    stats socket /run/haproxy/admin.sock mode 660 level admin
    stats timeout 30s
    user haproxy
    group haproxy
    daemon

defaults
    log     global
    option  tcplog
    timeout connect 5s
    timeout client  50s
    timeout server  50s

frontend mariadb_frontend
    bind 192.168.1.200:3306  # VIP and MariaDB port
    mode tcp
    default_backend mariadb_backend

backend mariadb_backend
    mode tcp
    balance roundrobin  # Distribute traffic evenly
    option tcp-check    # Health check for TCP (MariaDB port)
    server mariadb1 192.168.1.101:3306 check
    server mariadb2 192.168.1.102:3306 
    server mariadb3 192.168.1.103:3306

Once you update this config, you can move onto binding your VIP (Virtual IP) to your NIC.

Step 2: Bind VIP to NIC Manually

Now, we can bind the VIP you set in the config to the NIC. First, get the name of your NIC with the following command:

ip a

Look for something like ens18 or eno1. Once you know the name of your nic, use the following command to bind the VIP to the NIC:

sudo ip addr add <VIP>/32 dev <NIC_interface>

Verify the VIP is bound to the NIC with the same command:

ip a

Step 3: Make the VIP Persistent

On Debian, do this:

sudo nano /etc/network/interfaces.d/<interface>

Then, add:

auto  <interface>:0
iface <interface>:0 inet static
    address <VIP>
    netmastk 255.255.255.255

Then, restart networking:

sudo systemctl restart networking

On Ubuntu, find documentation:

 

 

 

 

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