Icinga seems to be randomly loosing connectivity to maps1002.eqiad.wmnet. maps1002 is not yet configured and only has the default puppet role applied. It is in scheduled downtime in Icinga, so those alerts are not sent. This server had some issue during initial installation (see T135018#2372770), which might or might not be related. I don't see anything strange in dmesg. /var/log/syslog indicates that diamond also has intermittent connection issues with Graphite.
This leads me to think that this is a more generic networking issue for that host.