Server Disk Space Check & mail notification

0-install.sh

#!/bin/sh

apt update && \
apt install postfix mailutils && \
# manually cofigure postfix with "Internet site"

echo "test" | mail your@email.com

1-disk-space.sh

# size limit you want to alert at
ALERT=200
UNIT=G
# Choose partition to check
PARTITION=/dev/nvme1n1

df -B$UNIT | grep "^$PARTITION" |
while read partition size used free perc mnt ;
do
        free_space=$(echo $free | tr -d $UNIT )
        if [ $free_space -le $ALERT ]; then
                echo "Partition $partition ($mnt) running out of space ($free) on $(hostname) as on $(date)" | mail -s "Alert: $mnt almost out of disk space on $(hostname) - $free" your@email.com,other@email.com
        fi
done

2-node-check.sh

IP=192.168.1.3
PORT=8545
curl "$IP:$PORT" \
  -X POST \
  -H "Content-Type: application/json" \
  --data '{"jsonrpc":"2.0","method":"eth_syncing","params":[],"id":67}'

retval=$?

if [ $retval -eq 0 ]; then
    echo OK
else
    echo "Node at address $IP (port $PORT) is not responding anymore on $(hostname) as of $(date)" | mail -s "Alert: node on $(hostname) / $IP stopped" your@email.com,other@email.com
fi

3-crontab

# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'
# command to install the new version when you edit this file
# and files in /etc/cron.d. These files also have username fields,
# that none of the other crontabs do.

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name command to be executed
17 *    * * *   root    cd / && run-parts --report /etc/cron.hourly
25 6    * * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
47 6    * * 7   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
52 6    1 * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
0 * * * * root bash /home/user/disk-space.sh

4-docker-checker

#!/bin/bash

CONTAINER_NAME=mycontainer

RESPONSE=$(docker ps -a | grep $CONTAINER_NAME)

if [ -n "$(echo $RESPONSE | grep -i 'exited')" ]
then 
    echo "$(date) Container $CONTAINER_NAME has exited, restarting..."
    docker restart $CONTAINER_NAME ;
    else 
        echo "$CONTAINER_NAME running..."
    fi
fi