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Setup a dedicated Debian subdomain (VM), Install MySQL 14 and connect to it from a WordPress on a different VM

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This is how I set up a dedicated Debian subdomain (VM), Installed MySQL 14 and connected to it from a WordPress installation on a different VM

Aside

If you have not read my previous posts I have now moved my blog to the awesome UpCloud host (signup using this link to get $25 free UpCloud VM credit). I compared Digital Ocean, Vultr and UpCloud Disk IO here and UpCloud came out on top by a long way (read the blog post here). Here is my blog post on moving fearby.com from Vultr to UpCloud.

Buy a domain name here

Domain names for just 88 cents!

Now on with the post.

Fearby.com

I will be honest, fearby.com is my play server where I can code, learn about InfoSec and share (It’s also my stroke rehab blog).

There is no faster way to learn than actually doing. The problem is my “doing” usually breaks the live site from time to time (sorry).

I really need to set up a testing environment (DEV-TEST-LIVE or GREEN-BLUE) server(s). GREEN-BLUE has advantages as I can always have a hot spare ready. All I need to do is toggle DNS and I can set the GREEN or BLUE server as the live server.

But first  I need to separate my database from my current fearby.com server and setup up a new web server. Having a Green and Blue server that uses one database server will help with near real-time production website switches.

Dedicated Database Server

I read the following ( Should MySQL and Web Server share the same server? ) at Percona Database Performance Blog. Having a separate database server should not negatively impact performance (It may even help improve speeds).

Deploy a Debian VM (not Ubuntu)

I decided to set up a Debian server instead of Ubuntu (mostly because of the good focus on stability and focus on security within Debian).

I logged into the UpCloud dashboard on my mobile phone and deployed a Debian server in 5 mins.  I will be using my existing how to setup Ubuntu on UpCloud guide (even though this is Debian).

TIP: Sign up to UpCloud using this link to get $25 free UpCloud VM credit.

Deploy Debian Sevrer

Deploy a Debian server setup steps:

  1. Login to UpCloud and go to Create server.
  2. Name your Server (use a fully qualified domain name)
  3. Add a description.
  4. Choose your data centre (Chicago for me)
  5. Choose the server specs (1x CPU, 50GB Disk, 2GB Memory, 2TB Traffic for me)
  6. Name the Primary disk
  7. Choose an operating system (Debian for me)
  8. Select an SSH Key
  9. Choose misc settings
  10. Click Deploy server

After 5 mins your server should be deployed.

After Deploy

Setup DNS

Login to your DNS provider and create DNS records to the new IP’s (IPv4 and IPv6) provided by UpCloud. It took DNS 12 hours to replicate to my in Australia.

Add a DNS record with your domain registra A NAMe = IPV4 and AAAA Name = IPv6

Setup a Firewall (at UpCloud)

I would recommend you set up a firewall at UpCloud as soon as possible (don’t forget to add the recommended UpCloud DNS IP’s and any whitelisted IP’s your firewall).

Block everything and only allow

  • Port 22: Allow known IP(s) of your ISP or VPN.
  • Port 53: Allow known UpCloud DNS servers
  • Port 80 (ALL)
  • Port 443 (ALL)
  • Port 3306 Allow your WordPress site and known IP(s) of your ISP or VPN.

Read my post on setting up a whitelisted IP on an UpCloud VM… as it is a good idea.

UpCloud thankfully has a copy firewall feature that is very handy.

Copy Firewall rules option at UpCloud

After I set up the firewall I SSH’ed into my server (I use vSSH on OSX buy you could use PUTTY).

I updated the Debian system with the following  command

Get the MySQL Package

Visit http://repo.mysql.com/ and get the URL of the latest apt-config repo deb file (e.g “mysql-apt-config_0.8.9-1_all.deb”). Make a temp folder.

Download the MySQL deb Package

Install the package

Update the system again

Install MySQL on Debian

Secure MySQL

You can secure the MySQL server deployment (set options as needed)

Install NGINX

I installed NGINX to allow Adminer MySQL GUI to be used

I ran these commands to install NGINX.

I edited my NGINX configuration as required.

  • Set a web server root
  • Set desired headers
  • Optimized NGINX (see past guides here, here and here)

I reloaded NGINX

Install PHP

I followed this guide to install PHP on Debian.

Install PHP FPM

Increase Upload Limits

You may need to temporarily increase upload limits in NGINX and PHP before you can restore a WordPress database. My feabry.com blog is about 87MB.

Add “client_max_body_size 100M;” to “/etc/nginx/nginx.conf”

Add the following to “/etc/php/7.2/fpm/php.ini”

  • post_max_size = 100M
  • upload_max_filesize = 100M

Restore a backup of my MySQL database in MySQL

You can now use Adminer to restore your blog to MySQL. Read my post here on Adminer here. I used Adminer to move my WordPress site from CPanel to a self-managed server a year ago.

First login to your source server and export your desired database then login to the target server and import the database.

Firewall Check

Don’t forget to allow your WordPress site’s 2x Public IP’s and 1x Private IP to access port 3306 in your UpCloud Firewall.

How to check open ports on your current server

Set MySQL Permissions

Open MySQL

I ran these statements to grant the user logging in on the nominate IP’s access to MySQL.

Reload permissions in MySQL

Allow access to the Debian machine from known IP’s

Edit “/etc/host.allow”

Additions (known safe IP’s that need access to this MySQL remotely).

Tell MySQL to listen on

Edit “/etc/mysql/my.cnf”

Added..

I guess you could change the port to something random???

Restart MySQL

Install a second local firewall on Debian

Install ufw

Do add the IP of your desired server or VPN to access SSH

Do add the IP of your desired server or VPN to access WWW

Now add the known IP’s (e.g any web servers public (IPv4/IPv6) or Private IP’s) that you wish to grant access to MySQL (e.g the source website that used to have MySQL)

Do add UpCloud DNS Servers to your firewall

Add all other rules as needed (if you stuff up and lock your self out you can login to the server with the Console on UpCloud)

Restart the ufw firewall

Prevent MySQL starting on the source server

Now we can shut down MySQL on the source server (leave it there just in case).

Edit “/etc/init/mysql.conf”

Comment out the line that contains “start on ” and save the file

and run

Reboot

Stop and Disable NGINX on the new DB server

We don’t need NGINX running now the database has been imported with Adminer.

Stop and prevent NGINX from starting up on startup.

Check to see if MySQL is Disabled

Yep

Test access to the database server in PHP code

Add to dbtest.php

<em>SELECT guid FROM wp_posts</em>()<br />
<ul><?php

//External IP (charged after quota hit)
//$servername = 'db.yourserver.com';

//Private IP (free)
//$servername = '10.x.x.x';

$username = 'username';
$password = '********your*password*********';
$dbname = 'database';

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$sql = 'SELECT guid FROM wp_posts';
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo $row["guid"] . "<br>";
    }
} else {
    echo "0 results";
}
$conn->close();
?></ul>
Done

Check for open ports.

You can install nmap on another server and scan for open ports

Install nmap

Scan a server for open ports with nmap

You should see this on a server that has access to see port 3306 (port 3306 should not be visible by non-whitelisted IP’s).  Port 3shouldoudl not be seen via everyone.

You should see something like this on a server that has access to see port 80/443 (a web server)

I’d recommend you use a service like https://pentest-tools.com/network-vulnerability-scanning/tcp-port-scanner-online-nmap# to check for open ports.  https://hackertarget.com/tcp-port-scan/ is a great tool too.

https://www.infobyip.com/tcpportchecker.php is also a free port checker that you can use to verify individual closed ports.

Screeshot of https://www.infobyip.com/tcpportchecker.php

Hardening MySQL and Debian

Read: https://www.debian.org/doc/manuals/securing-debian-howto/ap-checklist.en.html

Configuring WordPress use the dedicated Debian VM

On the source server that used to have MySQL edit your wp-config.php file for WordPress.

Remove

define('DB_HOST', 'localhost');

add (read the update below, I changed the DNS IP to the Private IP to have free traffic)

//Oriinal localhost
//define('DB_HOST', 'localhost');

//New external host via DNS (Charged after quota hit)
//define('DB_HOST', 'db.fearby.com');

//New external host via Private IP (Free)
define('DB_HOST','10.x.x.x');

Restart NGINX

Restart PHP-FPM

Conclusion

Nice, I seem to have shaved off 0.3 seconds in load times (25% improvement)

1sec gtmtrix load time

Update: Using a Private IP or Public IP between WordPress and MySQL servers

After I released this blog post (version 1.0 with no help from UpCloud) UpCloud contacted me and said the following.

I will have updated my references in this post and replace the public IP address (that is linked to DNS record for db.fearby.com) and instead use the private ip address (e.g 10.x.x.x), your servers private IP address is listed against the public IPv$ and IPv6 address.

I checked that the local ufw firewall did indeed allow the private IP access to MySQL.

On my new Debian MySQL server, I edited the file /etc/mysql/my.cnf and changed the IP to the private IP and not the public IP.

Now it looked like

(10.x.x.x  my Debian servers private IP)

On my WordPress instance, I edited the file  /www-root/wp-config.php

I added the new private host

//Oriinal localhost
//define('DB_HOST', 'localhost');

//New external host via DNS (Charged after quota hit)
//define('DB_HOST', 'db.fearby.com');

//New external host via Private IP (Free)
define('DB_HOST','10.x.x.x');

(10.x.x.x  my Debian servers private IP)

Alos on Debian/MySQL ensure you have granted access to the private IP of the WordPress server

Edit /etc/host.allow

Add

Restart MySQL

TIP: Enable UpCloud Backups

Do setup automatic backups (and or take manual backups). Backups are an extra charge but are essential IMHO.

UpCloud backups

Troubleshooting

If you can’t access MySQL log back into MySQL

and run

Reboot

Lower Upload Limits

Don’t forget to lower file upload sizes in NGINX and PHP (e.g 2M) now that the database has been restored.

I hope this guide helps someone.

TIP: Sign up to UpCloud using this link to get $25 free UpCloud VM credit.

https://www.upcloud.com/register/?promo=D84793

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Revision History

v1.6 Changed Public IP use to private IP use to ensure we are not charged when the serves sage goes over the quota

v1.5 Fixed 03 type (should have been 0.3)

v1.4 added disable nginx info

v1.3 added https://www.infobyip.com/tcpportchecker.php

v1.1 added https://hackertarget.com/tcp-port-scan/

v1.0 Initial Post