Custom text exporters for prometheus

fstab-mount-check

#!/bin/bash

# Reports on all filesystems declared in fstab, and if they are mounted or not - to detect unmounted filesystems

# NOTE: exporter info to stdout, human readable info to stderr
# in normal operation, pipe stdout to the datafile and stderr to null or syslog

# TODO : add a second error metric so that errors in this script are reported

tmpfile="$(mktemp)"
finalOut="$(mktemp)"

echo "# HELP node_filesystem_mounts_fstab_mounted Indicates if a filesystem in fstab is currently mounted" > "$finalOut"
echo "# TYPE node_filesystem_mounts_fstab_mounted gauge" >> "$finalOut"

# Get a list of all significant (non-comment/dupe) lines
cat /etc/fstab | grep -vE "^#" | uniq | sort > "$tmpfile"

# Loop through the lines
while read -r line
do
  blockDevice="$(echo "$line" | awk '{print $1}')"
  mountPoint="$(echo "$line" | awk '{print $2}')"
  type="$(echo "$line" | awk '{print $3}')"
  options="$(echo "$line" | awk '{for(i=4;i<=NF;i++){out=out" "$i}; print out}')"

  # skip things which are not valid mounts
  if [[ "$blockDevice" == "" || "$mountPoint" == "" ]] ; then
    echo "Skipping the following line as invalid. Note, it's probably a blank line." >>/dev/stderr
    echo "$line" >>/dev/stderr
    echo "" >>/dev/stderr
    continue
  fi
  echo "Found filesystem line to parse" >>/dev/stderr
  echo "BLOCK: $blockDevice" >>/dev/stderr
  echo "MOUNT: $mountPoint ">>/dev/stderr
  echo "TYPE: $type" >>/dev/stderr
  echo "OPTIONS: $options" >>/dev/stderr
  echo "" >>/dev/stderr

  # Check if mounted
  # More strict, breaks with uuids
  #mount | grep -E "^$blockDevice on $mountPoint type $type" &> /dev/null
  # ignores uuids
  mount | grep -E "^.* $mountPoint type $type" &> /dev/null
  if [[ "$?" == "0" ]] ; then
    isMounted="1"
  else
    isMounted="0"
  fi

  echo "node_filesystem_mounts_fstab_mounted{device=\"$blockDevice\",mountpoint=\"$mountPoint\",type=\"$type\"} $isMounted" >> "$finalOut"

  #printf '%s\n' "$line"
done < <(cat $tmpfile)

cat $finalOut

rm $tmpfile
rm $finalOut