9.8Grouped notifications
When several monitors fail at the same time, a channel gets one combined message instead of many. This is called grouping.
- The first alert to a channel goes out at once.
- Alerts to the same channel in the next 60 seconds are held. They are then sent together as one message.
- If alerts keep coming, you get about one combined message a minute.
- Reminders are grouped the same way. Acknowledgement notices are never grouped.
- If only one alert was held, it goes out as a normal message.
| Channel type | Grouped? |
|---|---|
| Email, Slack, Microsoft Teams, Discord, Telegram | Yes |
| Webhook, PagerDuty | Never. Every alert is its own request. |
What a combined message looks like#
The headline sums up the alerts, for example 5 more monitors are down or 3 more monitors are down, 1 recovered. For email, it is the subject, after [obsrvly]. Each monitor gets one line:
Down: <monitor> — <cause> — since 14:02:11 UTCA message lists at most 25 monitors, then and N more. It ends with: These alerts came within a minute of an earlier one on this channel, so they were sent together.
If a monitor recovers while its alert is held#
No separate down alert is sent. The combined message lists it as Recovered: <monitor>. If the recovery goes out alone, it says: No alert was sent when it went down. It recovered while alerts to this channel were being grouped.