Munin-limits seems to trigger notifications for any state change (OK->CRITICAL, OK->WARNING, WARNING->CRITICAL) bidirectionally. Is there a way to prevent Munin from notifying returns to "OK"?
I freely concede this question is about munin rather than NAGIOS. However, the two tools live hand-in-glove, and NAGIOS's notification engine is sophisticated and configurable, whilst munin's isn't. So instead of asking munin to notify you, have it inform NAGIOS and let NAGIOS do the notifying. Then you can set restrictions on time of day, use service escalations to notify management if problems persist, craft the form of the notification so as to be more appropriate to the medium (SMS and email notifications shouldn't look like each other), and, yes, control whether notification is sent on recovery.
In the contact template, or wherever this is defined for you, change
service_notification_options w,u,c,r,f,s host_notification_options d,u,r,f,s
service_notification_options w,u,c,f,s host_notification_options d,u,f,s
That is to say, remove the
r for recovery from both service and host notification options. Or you can override this on a contact-by-contact basis, in the contact's definition.
I must apologise to the author of this question because I am so habituated to having munin notify via NAGIOS - all my munin installations, and there are quite a few of them, do that - that I didn't originally notice that the question was munin-specific. However, my answer stands: if you want a notification engine that you can make configuration changes to, use a configurable engine.