ntp: New check for NTP clock condition.

diff --git a/check.d/ntp b/check.d/ntp
new file mode 100755 (executable)
index 0000000..68e8ac2
--- /dev/null
+++ b/check.d/ntp
@@ -0,0 +1,20 @@
+#! /bin/sh -e
+
+ntpdc -c peers | {
+  any=nil
+  while read remote local st poll reach delay offset disp; do
+    case "$remote" in
+      \**) ;;
+      *) continue ;;
+    esac
+    awk -v off="$offset" 'BEGIN {
+      if (off < 0) off = -off;
+      if (off >= 0.1) printf "W: absolute time offset %gs worrying\n", off;
+      else if (off >= 0.01) printf "I: absolute time offset %gs concerning\n", off;
+    }'
+    any=t
+  done
+  case $any in
+    nil) echo "W: not sychronized to any peer" ;;
+  esac
+}