Zonax7100
By:
Zonax7100

Automatically restart MySQL on Ubuntu 16.04.x - If statement may be wrong?

September 16, 2016 2.3k views
MySQL Ubuntu 16.04

Hey guys!

I have a Ubuntu 16.04.x server, where I installed MySQL.
Works great and everything, but I would like MySQL to be restarted if it, for any reason stops.
First of all, i know this isn't a very good solution, because there is a reason that the MySQL proccess stops. But I also have a Ubuntu 14.04.x server which has been running for over a year, where it happend 2 times. In these cases it would be really nice to get it up and running again. I have my logs to see why it went down.

So to the actual thing I need help with:

I found this script, that claims to be able to restart MySQL if it stops:

I have made a file called mysqlfix.sh in /root/

#!/bin/bash
PATH=/usr/sbin:/usr/bin:/sbin:/bin
if [[ ! "$(/usr/sbin/service mysql status)" =~ "start/running" ]]
then
    echo " The MySQL service on the server has been stopped. It has now been restarted." | mail -s " MySQL has been restarted" my@email.com
    sudo service mysql start
fi

Then made sure that it can run:

chmod +x mysqlfix.sh

Then added a cron job(crontab -e) that checks it every minute:

chmod +x mysqlfix.sh

This seems to be working on Ubuntu 14.04.x. But not on my new Ubuntu 16.04 server.
It sends me an E-mail every minute with the "The MySQL has been restarted" message.
This makes me think that the if statement is wrong. But I haven't been able to find what is wrong with it.

3 Answers
xMudrii September 16, 2016
Accepted Answer

Reason could be that Ubuntu 16.04.x is now using systemd instead of Upstart. This results in changed output of service status command.
When you run /usr/sbin/service mysql status in terminal you will notice this:

● mysql.service - MySQL Community Server
   Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2016-09-16 17:46:40 CEST; 1min 30s ago
  Process: 25747 ExecStartPost=/usr/share/mysql/mysql-systemd-start post (code=exited, status=0/SUCCESS)
  Process: 25744 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)
 Main PID: 25746 (mysqld)
    Tasks: 28
   Memory: 128.4M
      CPU: 265ms
   CGroup: /system.slice/mysql.service
           └─25746 /usr/sbin/mysqld

As far as you see, output is changed.
Most important change is this: Active: active (running).

So, if you change your if to: if [[ ! "$(/usr/sbin/service mysql status)" =~ "active (running)" ]], your script should be working fine.

Whole script for reference will be:

#!/bin/bash
PATH=/usr/sbin:/usr/bin:/sbin:/bin
if [[ ! "$(/usr/sbin/service mysql status)" =~ "active (running)" ]]
then
    echo " The MySQL service on the server has been stopped. It has now been restarted." | mail -s " MySQL has been restarted" my@email.com
    sudo service mysql start
fi

I have a similar script, but it can check other services as well. I recently updated it to work with 16.04:

https://github.com/sierracircle/services-checker

Hello, both of you.

Thanks for the feedback. That was pretty obvious, when you break it down.
I have marked xMudrii's answer as accepted, because it was a specific answer to the question.

But altso thanks to you sierracircle, I'll use your script instead. This way I can monitor more services.

Thanks to both of you!

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