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[How-To] Install HAProxy on Ubuntu 24.04 LTS

Purpose

Purpose description.

Prerequisites

List of prerequisites:

  • Root user or sudo user
  • Debian 12 LXC or VM

Instructions

Step 1: Update and Install HAProxy

Install haproxy

sudo apt update
sudo apt install -y haproxy


# Global settings
global
    log /dev/log local0
    log /dev/log local1 notice
    maxconn 4096
    user haproxy
    group haproxy
    daemon

# Default settings
defaults
    log global
    option httplog
    option dontlognull
    timeout connect 5000ms
    timeout client 50000ms
    timeout server 50000ms

# Frontend for MariaDB
frontend mariadb_frontend
    bind 192.168.1.100:3306      # Replace with your VIP and port
    mode tcp
    default_backend mariadb_backend

# Backend for MariaDB Galera Cluster
backend mariadb_backend
    mode tcp
    balance roundrobin          # Load balancing method (roundrobin, leastconn, etc.)
    option tcp-check            # Enable health checks
    tcp-check connect port 3306
    tcp-check expect response string "wsrep_local_state_comment: Synced"
    default-server inter 3s fall 3 rise 2 on-marked-down shutdown-sessions
    server mariadb1 192.168.1.101:3306 check   # Replace with actual IPs of your nodes
    server mariadb2 192.168.1.102:3306 check
    server mariadb3 192.168.1.103:3306 check

Here’s a quick guide to installing and configuring Keepalived on your MariaDB servers to manage a Virtual IP (VIP). This setup ensures high availability by automatically moving the VIP between the servers based on health checks.

1. Install Keepalived

Run the following command on each MariaDB server:

bash
sudo apt update sudo apt install -y keepalived

2. Configure Keepalived

Edit or create the Keepalived configuration file, usually located at /etc/keepalived/keepalived.conf.

Here’s a template for the configuration:

Primary Node Configuration (Master):

bash
vrrp_instance VI_1 { state MASTER interface eth0 # Replace with your actual network interface virtual_router_id 51 priority 100 # Higher priority on the master advert_int 1 authentication { auth_type PASS auth_pass securepassword } virtual_ipaddress { 192.168.1.100 # Replace with your VIP } track_script { chk_mariadb } } vrrp_script chk_mariadb { script "/usr/local/bin/check_mariadb.sh" interval 2 weight -20 }

Secondary Node Configuration (Backup):

The configuration is almost identical, but you’ll change the state and priority values:

bash
vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 90 # Lower priority on the backup advert_int 1 authentication { auth_type PASS auth_pass securepassword } virtual_ipaddress { 192.168.1.100 } track_script { chk_mariadb } } vrrp_script chk_mariadb { script "/usr/local/bin/check_mariadb.sh" interval 2 weight -20 }
  • Replace eth0 with your actual network interface (e.g., ens192 or similar).
  • Replace 192.168.1.100 with your desired VIP.
  • Replace securepassword with a strong password for authentication.

3. Create the MariaDB Health Check Script

Create the health check script at /usr/local/bin/check_mariadb.sh:

bash
#!/bin/bash if ! mysqladmin ping -h 127.0.0.1 --silent; then exit 1 fi exit 0
  • Ensure the script is executable:
bash
sudo chmod +x /usr/local/bin/check_mariadb.sh

4. Enable and Start Keepalived

Enable Keepalived to start on boot and then start the service:

bash
sudo systemctl enable keepalived sudo systemctl start keepalived

Check the status to ensure it’s running:

bash
sudo systemctl status keepalived

5. Test the VIP

  1. Verify the VIP (192.168.1.100 in this example) is active on the Master node:

    bash
    ip addr show

    You should see the VIP assigned to the specified interface.

  2. Stop Keepalived on the Master node:

    bash
    sudo systemctl stop keepalived

    The VIP should automatically move to the Backup node.

  3. Restart Keepalived on the Master and observe the VIP move back.

6. Optional: Add Logging

To troubleshoot Keepalived issues, you can enable verbose logging by editing /etc/sysconfig/keepalived or passing -D for debug mode.

Documentation Tips

  • Keepalived Configuration Path: /etc/keepalived/keepalived.conf
  • VIP Address: 192.168.1.100
  • Health Check Script Path: /usr/local/bin/check_mariadb.sh
  • VRRP Settings:
    • virtual_router_id: Unique ID (e.g., 51).
    • priority: Higher on Master, lower on Backup.
    • auth_pass: Password for VRRP authentication.

Would you like assistance verifying the Keepalived setup or testing failover scenarios?

 

 

 

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