diff --git a/CHANGELOG.md b/CHANGELOG.md
index a862784c..f1c2fbff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ System:
 * When upgrading, network checks like blocked port 25 are now skipped.
 * Tweaks to the intrusion detection rules for IMAP.
 * Improve the sort order of the domains in the status checks.
+* Munin was not working on machines confused about their hostname.
 
 v0.12c (July 19, 2015)
 ----------------------
diff --git a/setup/munin.sh b/setup/munin.sh
index 8ee0ae5b..87922ca6 100755
--- a/setup/munin.sh
+++ b/setup/munin.sh
@@ -28,5 +28,9 @@ contact.admin.command mail -s "Munin notification ${var:host}" administrator@$PR
 contact.admin.always_send warning critical
 EOF
 
+# ensure munin-node knows the name of this machine
+tools/editconf.py /etc/munin/munin-node.conf -s \
+	host_name=$PRIMARY_HOSTNAME
+
 # generate initial statistics so the directory isn't empty
 sudo -u munin munin-cron