Main & Backup Server

Setting Up Main & Backup Servers with Raspberry Pi 🍓

Prerequisites

• Two Raspberry-Pi
• Raspbian OS (Only CLI will also work, i.e Raspbian Lite) installed on both Pis
• Basic knowledge of terminal commands

Step 1: Install nala

nala is just a cover-up for apt. We will be using nala instead of apt for better readability.

sudo apt install nala -y

Step 2: Update both Raspberry Pi 🔄

Open the terminal on both Raspberry Pis and update the package list:

sudo nala update && sudo nala upgrade -y

Step 3: Install Apache2 🖥️

3.1 Install Apache on both Pi

sudo nala install apache2 -y

3.2 Start Apache2 Service on both Pi

sudo systemctl enable apache2
sudo systemctl start apache2

3.3 Verify Apache Installation 🌐

Open your web browser and visit http://. You should see the Apache2 default page.

Step 4: Install keepalived 🔧

4.1 Install keepalived

Install keepalived on both Raspberry Pis:

sudo nala install keepalived -y

4.2 Configure keepalived

Edit the keepalived configuration file on both Pi:

sudo nano /etc/keepalived/keepalived.conf

4.3 keepalived.conf Example

• For the Main Server (any one of the two Pi)

vrrp_instance VI_1 {
    state MASTER
    interface wlan0  # Change to your network interface (e.g., eth0 or wlan0)
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass secret  # Change this to a secure password
    }
    virtual_ipaddress {
        192.168.43.100  # Replace with your desired virtual IP
    }
}

Note

If you are using mobile hotspot as your local network, make sure that your virtual_ipaddress is withing the hotspot's IP Address's range.

• For the Backup Server (the other Pi)

vrrp_instance VI_1 {
    state BACKUP
    interface wlan0  # Change to your network interface (e.g., eth0 or wlan0)
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass secret  # Use the same password as the MASTER
    }
    virtual_ipaddress {
        192.168.43.100  # Use the same virtual IP as the MASTER
    }
}

Step 5: Start keepalived 🚀

Enable and start the keepalived service on both Pi:

sudo systemctl enable keepalived
sudo systemctl start keepalived

Verify Status

This will show if the service is activated or deactivated

sudo systemctl status keepalived

Step 6: Test Failover 🔄

1. Access the Virtual IP: Open a browser and go to http://192.168.43.100 (according to this eg.).
2. Stop keepalived on the Master:

   sudo systemctl stop keepalived

3. Check Failover: Refresh the browser; the backup server should take over.

Conclusion 🎉

You now have a main and backup server setup with two Raspberry Pis using Apache2 and keepalived! Enjoy your high availability web server! 🌟