update runbook repo to work with the new githost-prometheus cookbook

alerts/down.md

-Prometheus cannot reach this host.
-

alerts/githost.rules

+ALERT instance_20_disk
+  IF ((node_filesystem_avail{fstype=~"ext4|xfs"} / node_filesystem_size{fstype=~"ext4|xfs"}) * 100) < 20 AND ((node_filesystem_avail{fstype=~"ext4|xfs"} / node_filesystem_size{fstype=~"ext4|xfs"}) * 100) > 10
+  FOR 1m
+  LABELS { severity = "warn" }
+  ANNOTATIONS {
+    title = "Low disk space left on {{ $labels.mountpoint }} on {{ $labels.instance }}: {{ $value | humanize }}%",
+    description = "",
+    runbook="troubleshooting/filesystem_alerts.md",
+  }
+
+ALERT instance_10_disk
+  IF ((node_filesystem_avail{fstype=~"ext4|xfs"} / node_filesystem_size{fstype=~"ext4|xfs"}) * 100) <= 10
+  FOR 1m
+  LABELS { severity = "crit" }
+  ANNOTATIONS {
+    title = "Really low disk space left on {{ $labels.mountpoint }} on {{ $labels.instance }}: {{ $value | humanize }}%",
+    description = "",
+    runbook="troubleshooting/filesystem_alerts.md"
+    }
+
+ALERT down
+  IF up == 0
+  FOR 5m
+  LABELS { severity = "crit" }
+  ANNOTATIONS {
+    summary = "Instance {{ $labels.instance }} is down.",
+    description = "{{ $labels.instance }} is reporting as down, prometheus cannot reach the exporter.",
+    runbook="troubleshooting/instance_down.md"
+  }
\ No newline at end of file

alerts/instance_10_disk.md

-This instance has 10% or less disk space remaining.
-
-

alerts/instance_20_disk.md

-This instance has less 20% or less disk space left.
-
-