Getting multiple Notifications per alert

icinga2 - The Icinga 2 network monitoring daemon (version: r2.10.5-1)

I am member of two groups. There is one service, that has notification assigned to both of that groups. Result is that I get two notifications for that service.

If I remember correctly, wasnt there a mechanism to prevent notifications getting sent to the same person multiple times? Like a filter before sending?

Yes, while your user is in two groups, it is still only one user and so only should get one notification.

Just to ensure and because I had an similar issue in the past, there are not two different users with your mail address or a mailing list (probably the wrong term) containing your email as a second user?

Good idea, but no. Every user and every email address is unique.

What do you see in /var/log/icinga2/icinga2.log with the label
“informaton/Notification”?

Does it show the machine sending two notifications at the same time?

Does it show any difference between the reasons for those notifications being
sent?

Antony.

Another idea: Can you see the sending system in the email header? If notification feature is enabled somewhere else a different host like a satellite could be sending.

Yes, I do see two notifications being sent, the reason seems to be that two notification rules hit. My user is member of two groups that receive notification for a service.
Checking the group settings and the log it looks to me like Icinga is going though the groups and sends notifications - without checking if that user has got notification about this issue before.

object User "MY-USER" {
   import "generic-user"
   display_name = "THIS IS ME"
   groups = [ "oncall", "sdm", "veeam-admins" ]
   email ="MY EMAIL"
}

apply Notification "mail-bereitschaft" to Service {
   import "mail-service-notification"
   user_groups = [ "oncall" ]
   states = [ Warning, Critical, OK, Unknown ]
   interval = 12h
  assign where service.vars.oncall
}

apply Notification "veeam-alert" to Service {
   import "mail-service-notification"
   user_groups = [ "veeam-admins","sdm" ]
   interval = 0
   assign where service.vars.veeam_alert
}
230835 [2021-06-10 06:14:51 +0200] information/Checkable: Checking for configured notifications for object 'HOST!Veeam Backup Success Percent'
230836 [2021-06-10 06:14:51 +0200] information/Notification: Sending 'Problem' notification 'HOST!Veeam Backup Success Percent!mail-bereitschaft' for user 'MY-USER'
230837 [2021-06-10 06:14:51 +0200] information/Notification: Sending 'Problem' notification 'HOST!Veeam Backup Success Percent!veeam-alert' for user 'USER1'
230838 [2021-06-10 06:14:51 +0200] information/Notification: Sending 'Problem' notification 'HOST!Veeam Backup Success Percent!veeam-alert' for user 'USER2'
230839 [2021-06-10 06:14:51 +0200] information/Notification: Sending 'Problem' notification 'HOST!Veeam Backup Success Percent!veeam-alert' for user 'USER3'
230840 [2021-06-10 06:14:51 +0200] information/Notification: Sending 'Problem' notification 'HOST!Veeam Backup Success Percent!veeam-alert' for user 'USER$'
230841 [2021-06-10 06:14:51 +0200] information/Notification: Sending 'Problem' notification 'HOST!Veeam Backup Success Percent!veeam-alert' for user 'MY-USER'

Also a good idea, but I got only one master configured to send notifications. Sadly, the header is being cleaned befroe it leaves the company, so I don’t see the details interesting to us.