Notification bundling is PagerDuty's term for the incident summary we switch to when multiple incidents are triggered and assigned to a user.
PagerDuty's mission is to notify you to the incidents you need to know about, at the level you need to know them. This directive becomes complicated when your notification volume explodes: if 100 notifications a minute are incoming, what is the best way to notify you?
Normally, we would notify you for each individual incident. However, if your notification method is set to phone, and your phone starts ringing off the hook until 100 consecutive phone calls and voicemails are pushed through, the problem becomes serious. We call these "notification storms," and calibrate our policies to avoid this.
Notification bundling means we roll together or bundle these multiple notifications into a single summarizing notification, regardless of your notification method (phone, SMS, email, or push). All incidents that are in the triggered state (i.e. not acknowledged or resolved) will be included in the bundled notification.
Here are examples of how each contact method will notify you, in the event of near-simultaneous incidents. For this example, assume I've triggered 5 incidents on a service named "Nagios" within a 1-minute time frame.
You have 5 triggered incidents on Nagios. Press 4 to acknowledge all incidents. Press 6 to resolve all incidents. Press 0 for help or press * to repeat this message.
ALRT: #100,#101,#102,#103,#104 on Nagios. Reply 14:Ack all, 16:Resolv all
You are assigned 5 triggered incidents in PagerDuty:
Please visit the following URL to manage these incidents.
1) Incident #100
Opened on: Jan 1 at 12:00pm PST
Description: Emergency in the server room
Another way to minimize the number of notifications that you receive is to adjust your notification rules so that you are notified of an incident several minutes after it is assigned to you as opposed to immediately after it is assigned to you. Adjusting the notification rules will allow more time for incidents to aggregate and you will receive fewer notifications during a notification storm.