Systemd Service / Timer

1. Create Systemd Service File (e.g. wan-failover.service):

• Purpose: Defines how the failover script is run and managed by systemd.

• Key Sections:

  • [Unit]: Description, dependencies (e.g., network target)

  • [Service]: Specifies the script to execute (ExecStart), user/group, restart policy (e.g., always restart on failure)

  • [Install]: Defines when the service should be enabled (e.g., multi-user.target)

[Unit]
Description=WAN Failover Service
After=network-online.target
Wants=network-online.target

[Service]
Type=oneshot
ExecStart=/path/to/wan-failover.sh
Restart=on-failure
RestartSec=10
User=cardano

[Install]
WantedBy=multi-user.target

• ExecStartPre=/bin/sleep 10: You might add a delay to allow network to initialize before running the script.

1. Create Systemd Timer File (e.g. wan-failover.timer):

• Purpose: Periodically triggers the failover script.

[Unit]
Description=Timer for WAN Failover Script
[Timer]
OnBootSec=1min
OnUnitActiveSec=30
AccuracySec=10

[Install]
WantedBy=timers.target

• This example runs the timer 1 minute after boot and then every 30 seconds. You can adjust these settings

1. Installation:

• Save the script: Place the wan-failover.sh script in a suitable location (e.g., /usr/local/bin )

• Create the service file: Save the wan-failover.service file in /etc/systemd/system/

• Create the timer file: Save the wan-failover.timer file in /etc/systemd/system/

• Enable and start

1. To start WAN Failover as a service when the computer boots, type:

sudo systemctl daemon-reload
sudo systemctl enable wan-failover.service

1. Managing Services

To help administer an instance of WAN Failover running as a systemd service, use the following commands:

• To view the status of the WAN Failover service, type:

sudo systemctl status wan-failover.service

• To restart the WAN Failover service, type:

sudo systemctl reload-or-restart wan-failover.service

• To stop the WAN Failover service, type:

sudo systemctl stop wan-failover.service

• To display the logs of WAN Failover service, type:

sudo journalctl -u wan-failover.service -f -o cat