ONLINE Alert (Node Returned to Operation)

Why do you receive this message?

The ONLINE alert is sent when the system detects that the node returned to operation after a failure period. You receive it when:

• The node responds to HTTP queries again
• Status changes from OFFLINE to ONLINE
• The system successfully retrieved metrics from the node

✅ Good news!

The node is working again. Check if it's synchronized and if everything works normally.

What does the message contain?

• Recovery image - Sent as the first message
• Status - ✅ ONLINE – Responding to requests
• Detection time - Exact timestamp of return to operation
• Failure duration (if available):
  • Duration - time from last_down_at to now
  • Last known OFFLINE event - when the node stopped working
• Summary - Information about node return to operation
• Recommendations - Check synchronization and stability

How should you react?

1. Check synchronization:

   • Open the monitoring panel
   • Check if the node is synchronized (block difference ≤ 5)

2. Check logs (if the failure was long):

   journalctl -u redbelly.service --since "1 hour ago"

3. Check stability:

   • Is the node staying ONLINE?
   • Are there frequent ONLINE/OFFLINE switches (flapping)?

4. If the node frequently switches:

   • Check system resources (CPU, RAM, disk)
   • Check logs for errors
   • Check network connection

Sending Logic

Element	Details
Trigger	Status change from OFFLINE → ONLINE in background_monitor() function
Check frequency	Every 15 seconds (each monitoring cycle)
Conditions	• previous_online_status != is_online • is_online == True • Telegram alerts enabled • Uses last_down_at to calculate failure time
Format	First image, then text message in Markdown
Duplicate prevention	Alert sent only on status change