How to Replace MySQL with Percona on Plesk CentOS 7

This article outlines the procedure for replacing the native MySQL®️ or MariaDB®️ service that is preinstalled on any typical Plesk Onyx 11 CentOS 7 server. The procedure outlines removal of the existing MySQL related binaries and replaces them with an adequate version of the Percona binaries. Once these Percona binaries are in place, a typical multistage MySQL Incremental version upgrade is processed to bring the existing databases and Percona binaries to the desired Percona 5.7 version.

Maintenance Expectations: Length & Downtime

Suggested Maintenance Duration:  90 minutes
Minimum Expected Downtime: ~30 minutes of service flapping

The expected MySQL service downtime for this procedure is less than 30 minutes of MySQL service availability going up and down repeatedly (flapping). This figure assumes that all goes smoothly and no unforeseen errors are encountered. The suggested maintenance length allows time for troubleshooting should error arise as well as an extra 30 minutes in the unlikely event that all changes need to be reverted and the maintenance plan aborted.

 

Maintenance Stages Overview

The plan is broken up into preparation tasks and stages. Preparation tasks should be completed prior to the start time of your maintenance window. Stages are conducted throughout the maintenance event window and walk through the entire procedure for accomplishing each important stage of the outline.

Preparation – Pre Maintenance Tasks

These two important tasks must be completed prior to the scheduled start time of your maintenance window:

  • Copy existing MySQL config file
  • Stage backup of MySQL database data

We use stage zero in this plan to help expedite the backup process of the MySQL data. Since the amount of data MySQL will hold varies wildly per server, it is a good practice to run an incremental backup solution, like rsync, prior to the maintenance event window. Rsync will backup the majority of static data while MySQL is still running and then will backup the incremental difference once MySQL is shut down for maintenance.

Copy existing MySQL config file:
1) Make a backup copy of the existing myself config file.

cp -pv /etc/my.cnf{,.pre-percona.bak}

Stage backup of MySQL database data:

2) Run the following rsync to clone the MySQL data. [IMPORTANT: trailing slash required]

rsync -vaH /var/lib/mysql{,.pre-percona}/

Note:
Very Large databases will take considerably longer to complete so plan accordingly.

3) Wait for step 1 to complete before starting Stage 1.

 

Stage 1 – Shutdown MySQL & Rerun Rsync Final Sync

The purpose of stage one is to ensure a pristine backup of the MySQL data is in place before proceeding. To accomplish this, it is necessary to completely stop MySQL services so all buffers are written and no additional changes are being written to the database. Once stopped, rsync is executed again to copy the differences between the now stopped pristine data and the target backup data.

1) Shutdown MySQL/MariaDB Service

systemctl stop mysql

2) Rerun the following rsync to finalize the cloned data. [IMPORTANT: trailing slash required]

rsync -vaH /var/lib/mysql{,.pre-percona}/

3) Wait for rsync to complete before moving on to Stage 3.

 

Stage 2 – Replace MariaDB 5.5 Binaries With Percona 5.5

NOTE:
MariaDB 5.5 is the version installed with Onyx 11 CentOS 7, so this is the starting point.

Replacing the existing binaries involves removing the necessary binary packages from the system using the RPM command line tool instead of yum. This allows the packages to be removed without touching any of the dependencies linking to other system packages. Since Percona, like MariaDB, is a drop-in replacement for MySQL, once the new binaries are in place the linked dependencies won’t know the difference and will function normally.

1) Remove MariaDB packages without dependencies:

rpm -e --nodeps mariadb mariadb-libs mariadb-server

2) Remove mariadb-devel package (do this as a separate command from above to avoid removal failure do to missing package)

rpm -e --nodeps mariadb-devel

3) Install Percona repository:

yum install https://www.percona.com/redir/downloads/percona-release/redhat/percona-release-0.1-4.noarch.rpm

4) Install Percona DB server:

yum install Percona-Server-client-55 Percona-Server-server-55 Percona-Server-shared-55

5) Execute the following commands (allows InnoDB plugin to load correctly)

mv /var/lib/mysql/ibdata1 /var/lib/mysql/ibdata1.bak
cp -a /var/lib/mysql/ibdata1.bak /var/lib/mysql/ibdata1
mv /var/lib/mysql/ib_logfile0 /var/lib/mysql/ib_logfile0.bak
cp -a /var/lib/mysql/ib_logfile0.bak /var/lib/mysql/ib_logfile0
mv /var/lib/mysql/ib_logfile1 /var/lib/mysql/ib_logfile1.bak
cp -a /var/lib/mysql/ib_logfile1.bak /var/lib/mysql/ib_logfile1

6) Make sure that there are no processes listening on port 3306 and kill the process if any.

netstat -tulpn | grep 3306

7) Start MySQL (now Percona 5.5)

service mysql start

8) Run mysql_upgrade script

mysql_upgrade -uadmin -p`cat /etc/psa/.psa.shadow`

9) [Optional]  Enable Percona XtraDB Cluster UDF from Percona Toolkit:

plesk db -e "CREATE FUNCTION fnv1a_64 RETURNS INTEGER SONAME 'libfnv1a_udf.so'"
plesk db -e "CREATE FUNCTION fnv_64 RETURNS INTEGER SONAME 'libfnv_udf.so'"
plesk db -e "CREATE FUNCTION murmur_hash RETURNS INTEGER SONAME 'libmurmur_udf.so'"

10) Restart MySQL to complete upgrade procedure

systemctl start mysql

 

Stage 3 – Switch Plesk MySQL Package over to the Plesk MySQL Community package

Running Percona on Plesk is an unsupported configuration. For this reason, to satisfy dependency connections between the Plesk MySQL package and the new Percona binaries, it is necessary to switch the Plesk MySQL release over to using the Plesk MySQL Community release instead. The change is necessary to facilitate upgrading and downgrading Percona versions.

1) Create the necessary repo config file:

printf '[PLESK_17_8_11-dist] %s\nname=PLESK_17_5_3 dist %s\nbaseurl=http://autoinstall.plesk.com/PSA_17.8.11/dist-rpm-CentOS-7-x86_64/ %s\nenabled=1 %s\ngpgcheck=1 %s\n' > /etc/yum.repos.d/plesk178.repo

2) Install “plesk-mysql-server-community” package from the new repository:

yum install plesk-mysql-server-community

3) Disable /etc/yum.repos.d/plesk178.repo file as it’s no longer needed:

mv /etc/yum.repos.d/plesk178.repo{,.disabled}

4) Remove ”plesk-mysql-server” package without touching dependencies.

rpm -e --nodeps plesk-mysql-server

 

Percona should now be installed and working on the base 5.5 version. The next stages are identical to the typical MySQL upgrade process where binaries are upgraded, and then the schema updates are made manually using the mysql_upgrade tool.

Upgrade Percona 5.5 to 5.6

1) Stop MySQL service:

service mysql stop

2) Remove Percona 55 packages without dependencies:

rpm -e --nodeps Percona-Server-shared-55 Percona-Server-client-55 Percona-Server-server-55

3) Install Percona 56 packages

yum install Percona-Server-shared-56 Percona-Server-client-56 Percona-Server-server-56

4) Make sure that there are no processes listening on port 3306 and kill the process if any.

netstat -tulpn | grep 3306

5) Start the MySQL service:

service mysql start

6) Upgrade MySQL tables:

mysql_upgrade -uadmin -p`cat /etc/psa/.psa.shadow`

 

Stage 4 – Upgrade Percona 5.6 to 5.7

1) Stop MySQL service:

service mysql stop

2) Remove Percona 56 packages without dependencies:

rpm -e --nodeps Percona-Server-shared-56 Percona-Server-client-56 Percona-Server-server-56

3) Install Percona 57 packages

yum install Percona-Server-shared-57 Percona-Server-client-57 Percona-Server-server-57

4)  Make sure that there are no processes listening on port 3306 and kill the process if any.

netstat -tulpn | grep 3306

5) Start the MySQL service:

service mysql start

6) Upgrade MySQL tables:

mysql_upgrade -uadmin -p`cat /etc/psa/.psa.shadow`

 

Stage 5 – Finalizing Upgrade

The system should now be running Percona 5.7 and be fully accessible by applications. At this stage, any sites or application using a database should be tested and any errors investigated.

Install Java 8 on CentOS 7

In this tutorial, we’ll be showing you how to install Oracle’s Java 8 programming language specifically onto a CentOS 7 server. This simple object-oriented language is used for many of the applications and websites you come across today.  Let’s jump right in!

Pre-flight

  1. Open the terminal and login as root.  If you are logged in as another user, you will need to add sudo before each command.
  2. Working on a Linux CentOS 7 server
  3. No installations of previous Java versions

Installing Java 8 on CentOS 7

Step 1: Update

As a matter of best practice we’ll update before installing any new programs:

yum -y update

Step 2: Install Java 8

yum install java-1.8.0-openjdk

Step 3:  Verify Java is Installed

java -version

Example Output:

java -version
openjdk version "1.8.0_191"
OpenJDK Runtime Environment (build 1.8.0_191-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)

Set Java’s Home Environment

Step 1: Find Java’s Path

Let’s set the JAVA_HOME variable, using the following command will give us a path so we can set the variable.

update-alternatives --config java

You’ll see a prompt to “Enter to keep the current selection[+], or type selection number:”, if you had multiple Java version you could set the default here, but all we need is the path of Java so we can exit pressing enter.  The highlighted area is the path we will need to copy/paste into our .bash_profile file.

Selection    Command
-----------------------------------------------
*+ 1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/jre/bin/java)</code?

Step 2: Setting Java’s Path in Your Environment

After copying your Java’s path, open the .bash_profile with your text editor.

vim .bash_profile

Export your Java path into the .bash_profile by adding the following to the bottom of the file. (Your path may look different from mine, and it’s not important that they vary.)

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/jre/bin/java

Refresh the File:

Source .bash_profile

When you use the JAVA_HOME variable you’ll now be able to see the path you set.

echo $JAVA_HOME

Example Output:

/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/jre/bin/java

 

Transfer an SSL to Ubuntu 16.04 or CentOS 7

SSL certificates have become a de facto part of every website. If you don’t yet have an SSL on your site to encrypt data, you should. Rather than showing an extra layer of security on sites protected by SSL, modern browsers instead now display a warning when a website does not have an SSL, essentially requiring sites to maintain their positive image.

When moving from one server to another, what needs to happen to your SSL to maintain your secure status? We’ll cover the basics for transferring traditional and Let’s Encrypt SSLs to Ubuntu 16.04 and CentOS 7.

Note:
This article will address SSLs in Apache specifically, but the same concepts apply to any service that supports SSL encryption.

Can SSLs be transferred between servers?

Continue reading “Transfer an SSL to Ubuntu 16.04 or CentOS 7”

How to Use Ansible

Ansible symbolAnsible is an easy to use automation software that can update a server, configure tasks, manage daily server functions and deploys jobs as needed on a schedule of your choosing. It is usually administered from a single location or control server and uses SSH to connect to the remote servers. Because it employs SSH to connect, it is very secure and, there is no software to install on the servers being managed. It can be run from your desktop, laptop or other platforms to assist with automating the tedious tasks which every server owner faces.

Continue reading “How to Use Ansible”

Apache Performance Tuning: Configuring MPM Directives

 

Our previous article in this series focused on defining and fitting MPM to match your environment.  Building off of our last tutorial we will be discussing specific details on how to adjust the previously mentioned Apache configuration directives on the various types of Liquid Web servers.  

Continue reading “Apache Performance Tuning: Configuring MPM Directives”

What is mod_deflate?

How mod_deflate works

When a visitor accesses a website, a request is made to the web server for a specific kind of data. An example might be a home page of a site. Next, the web server locates that data and delivers it to the client who is requesting that data – basically back to the web browser.

In this example, the speed at which the home page loads can depend on a variety of factors. One of them could be how long it takes to find and deliver the data for that page. This is just one example.

Some of that data – such as javascript files, css files, and php files – can actually be compressed into smaller sizes before they are delivered back to the visiting client or browser at the smaller size. The visitor can now have a more optimized browsing experience.

This is where mod_deflate comes in.

Continue reading “What is mod_deflate?”

Generating a Certificate Signing Request (CSR) in CentOS

This guide will walk you through the steps to create a Certificate Signing Request, (CSR for short.) SSL certificates are the industry-standard means of securing web traffic to and from your server, and the first step to getting your own SSL is to generate a CSR. This guide is written specifically for CentOS 7.

Continue reading “Generating a Certificate Signing Request (CSR) in CentOS”

How to Install and Configure vsftpd on CentOS 7

FTP (File Transfer Protocol) is one of the most popular methods to upload files to a server. There exist a wide array of FTP servers, such as vsftpd, you can use and FTP clients exist for every platform.

Essentially no matter what OS you use you can find an easy to use FTP client, so it makes for a great solution to transfer files. On CentOS based servers before you can connect via FTP you’ll have to setup an FTP server. Here we’re gonna setup vsftpd which is a great option since it has a focus on security and speed.

Continue reading “How to Install and Configure vsftpd on CentOS 7”

How to enable EPEL repository?

The EPEL repository is an additional package repository that provides easy access to install packages for commonly used software. This repo was created because Fedora contributors wanted to use Fedora packages they maintain on RHEL and other compatible distributions.

To put it simply the goal of this repo was to provide greater ease of access to software on Enterprise Linux compatible distributions.

What’s an ‘EPEL repository’?

The EPEL repository is managed by the EPEL group, which is a Special Interest Group within the Fedora Project. The ‘EPEL’ part is an abbreviation that stands for Extra Packages for Enterprise Linux. The EPEL group creates, maintains and manages a high quality set of additional packages. These packages may be software not included in the core repository, or sometimes updates which haven’t been provided yet.
Continue reading “How to enable EPEL repository?”

Fully Managed Templates Now Optimized with FCGI

Note:
Please note that this article is considered legacy documentation for an older account management system.

Your fully managed cPanel server has several different PHP handlers from which to choose, including DSO, SuPHP, and FCGI. These handlers are responsible for reading/interpreting PHP code, then compiling and executing it.

Selecting the best PHP handler for your server is critical to overall performance, but it’s not always an easy choice to make. While FCGI currently is the best-performing PHP handler available on cPanel, it can be somewhat difficult to properly configure.

Since we’re the best Managed Hosting company around, we decided to take care of the initial configuration for you to help make your decision that much easier.

Liquid Web has spent the past few months optimizing FCGI settings to achieve the best performance gains possible while lowering resource utilization and further improving stability. Today, we’re thrilled to announce that we’ve updated our Fully Managed CentOS 6 and CentOS 7 templates to include these optimizations by default!

What type of performance gain does FCGI provide over SuPHP? We’re glad you asked!

To measure performance, we installed a default WordPress site on a Zone C 16 GB Storm VPS, then used Apache Benchmark to hit the server with 10 concurrent connections, and a total of 1,000 requests.

PHP with FCGI and OPcache performed 5 times faster than suPHP in this simpla Apache Benchmark test

With SuPHP as the PHP handler, we were able to get around 30 requests per second. Once we switched the PHP handler to FCGI with our optimizations (which include enabling and configuring OPcache), we were able to get more than 150 requests per second! In this case we saw a 500% increase in performance!

These optimizations are not reserved for new Storm® VPS and Dedicated servers, either. If you have an existing fully managed cPanel server and would like to take advantage of the performance gains FCGI and OPcache can bring to your sites, let us know! Our Heroic Support® technicians can quickly examine your server’s current settings and walk you through any changes necessary to help your server realize its full potential with FCGI and OPcache.