Bash Script for Nagios to Check Status of Docker Container

check_docker_container.sh

#!/bin/bash

# Author: Erik Kristensen, Lorenzo Gaggini
# Email: erik@erikkristensen.com, lorenzo.gaggini@dada.eu
# License: MIT
# Nagios Usage: check_nrpe!check_docker_container!_container_id_
# Usage: ./check_docker_container.sh _container_id_
#
# The script checks if a container is running and grab performance data
#   OK - running
#   WARNING - container is ghosted
#   CRITICAL - container is stopped
#   UNKNOWN - does not exist

CONTAINER=$1

RUNNING=$(docker inspect --format="{{ .State.Running }}" $CONTAINER 2> /dev/null)

if [ $? -eq 1 ]; then
  echo "UNKNOWN - $CONTAINER does not exist."
  exit 3
fi

if [ "$RUNNING" == "false" ]; then
  echo "CRITICAL - $CONTAINER is not running."
  exit 2
fi

GHOST=$(docker inspect --format="{{ .State.Dead }}" $CONTAINER)

if [ "$GHOST" == "true" ]; then
  echo "WARNING - $CONTAINER is dead."
  exit 1
fi

STARTED=$(docker inspect --format="{{ .State.StartedAt }}" $CONTAINER)
NETWORK=$(docker inspect --format="{{ .NetworkSettings.IPAddress }}" $CONTAINER)

STATS=$(docker stats --no-stream $CONTAINER | tail -1)
CPU=$(echo $STATS | awk '{print $2}')
MEMUSAGE=$(echo $STATS | awk '{print $6}')
MEMUSED=$(echo $STATS | awk '{print $3$4}' | cut -d '/' -f1)
NETIN=$(echo $STATS | awk '{print $7$8}' | cut -d '/' -f1)
NETOUT=$(echo $STATS |  awk '{print $8$9}' | cut -d'/' -f2)

echo "OK - $CONTAINER is running. IP: $NETWORK, StartedAt: $STARTED | cpu=$CPU mem=$MEMUSAGE memused=$MEMUSED netIn=$NETIN netOut=$NETOUT"