Co-Author: Rafael Alvarez

When you look up the word idempotence in wikipedia you get the following definition: Idempotence is the property of certain operations in mathematics and computer science whereby they can be applied multiple times without changing the result beyond the initial application.

When I think of idempotence in the sense of how IT operations work, the very first thing that comes to mind is Ansible. In Ansible you have a yml file that represents a state you want the target host to be in. For example, I can use the yum module to ensure that MySQL is installed on my RHEL virtual machine. When the playbook is run, it checks if MySQL is installed. If not, it will install it. It is installed, then it will ignore that …

MySQL privilege system is small, almost all administrative tasks can be completed using a handful of privileges. If we exclude generic ones as ALL, SHOW DATABASES and USAGE, create and drop permissions as CREATE USER, DROP ROLE or CREATE TABLESPACE, the number of privileges remaining is really limited: PROCESS, PROXY, RELOAD, REPLICATION_CLIENT, REPLICATION_SLAVE, SHUTDOWN and SUPER.

Having such a reduced list of privileges means that it is very difficult to control what a connected session can do. For example, if a user has privileges to stop replication, it also has privileges to start it, and also to configure it. Actually, it has rights to do almost everything as the privilege required to stop replication is …

Everyone knows those situations where there is a task that you need to do and you want to do, but you just don’t come around to actually doing it. Well, for me, this new release was such a task.

Early in 2017, I released the first version of puppet-proxysql on GitHub. It was my first puppet-module release and I was quite proud of it. I had implemented types and providers for managing the ProxySQL resources such as mysql_user, mysql_servers, etc…

At Config Management Camp Gent (February 2017) I met Vox Pupuli, who is the group that forms the puppet-user-community. They picked up the responsibility of taking ownership of well-known modules that are left unmaintained or abandoned and/or modules that only had a single maintainer. The puppet-proxysql module was kind of the latter. Additionally, they …

In this blog post, I’ll walk you through setting up encrypted replication on MySQL 5.7 with GTID enabled. I will walk you through how to create sample certificates and keys, and then configure MySQL to only use replication via an encrypted SSL tunnel.

For simplicity, the credentials and certificates I used in this tutorial are very basic. I would suggest, of course, you use stronger passwords and accounts.

Let’s get started.

Create a folder where you will keep the certificates and keys

mkdir /etc/newcerts/
cd /etc/newcerts/

Create CA certificate

[root@po-mysql2 newcerts]# openssl genrsa 2048 > ca-key.pem
Generating RSA private key, 2048 bit long modulus
.............+++
..................+++
e is 65537 (0x10001)

[root@po-mysql2 newcerts]# openssl req -new -x509 -nodes -days 3600 -key ca-key.pem -out ca.pem
You are about to be asked to enter …

“We made it a point to hire really smart, visionary people and then let them do their work.
I wanted to delegate and let people be in charge of things. My own decision-making process was to decide who got to decide. To make decisions, you have to first outline the problem, and if you hire really great people, they’re going to know more about the problem they’re dealing with than you ever will.”–Scott McNealy

I have interviewed Scott McNealy. Scott is a Silicon Valley pioneer, most famous for co-founding Sun Microsystems in 1982. We talked about Innovation, AI, Big Data, Redis, Curriki and Wayin.

RVZ

Q1. You co-Founded Sun Microsystems in 1982, and served as CEO and Chairman of the Board for 22 years. What are the main lessons learned in all these years?

Scott …

One problem that’s a lot less common these days is swapping. Most of the issues that cause swapping with MySQL have been nailed down to several different key configuration points, either in the OS or MySQL, or issues like the swap insanity issue documented by Jeremy Cole back in 2010. As such, it’s usually pretty easy to resolve these issues and keep MySQL out of swap space. Recently, however, we had tried all of the usual tricks but had an issue where MySQL was still swapping.

The server with the issue was a VM running with a single CPU socket (multiple cores), so we knew it wasn’t NUMA. Swappiness and MySQL were both configured correctly and when you checked the output of free -m it showed 4735M of memory available.

[sylvester@host~]$ free -m
              total        used        free      shared  buff/cache   available …

I’ve been posting quite a bit about Docker as I’ve been working with it a lot as of late. I thought I would share something interesting I discovered a couple weeks ago while working on setting up a Docker container-based lab environment for training purposes here at Pythian, specifically when attempting to install the MySQL-python package inside the container.

I know what you’re thinking: why is he trying to install a package in a Docker container? Doesn’t that go against the “Docker run and forget about it” philosophy? Sure, but in this case, I’m looking to add orchestration via ansible, which I don’t think is completely out of the question in order to coordinate your Docker containers for something like replication. This requires using the …

There are numerous ways to filter your replication stream in MySQL.  So many, that the documentation team has created guided “walk-through” pages for considering the various complex DB Filtering and subsequent Table Filtering paths folks have used for the “global” filtering options.  But now there are “channel specific” options that can be implemented at startup with enhanced… Read More »

In one of the projects I have been working on, one requirement was the ability to stop traffic from reaching a MySQL host which has been lagging behind its master for longer than a specific amount of time and then bring it back online once the lag has gone away. Of course, this is all automated and no human intervention is required.

In this scenario, we are using HAProxy as the load balancer, and I will walk you through how to configure an agent so we can use HAProxy httpchk to flag the host as up or down, via systemd socket and then automatically set the host as being down/up when applicable, in HAProxy.

I will be setting up a systemd service (I’m running centos7 hosts) and creating a listening socket in the MySQL host we want to monitor so haproxy can have access to replication status.

Scenario:

master: po-mysql1
slaves: po-mysql2, po-mysql3, po-mysql4
secondary slaves: …

In a previous post I had mentioned that I was doing a bit of digging into Docker in order to get a better grasp of the technology. Part of that was exploring common administrative tasks. I would venture to say that backups are probably among the most important tasks we take on with database administration, so it’s important to know how to do this for Docker MySQL instances.

There is a fair bit of documentation on how to handle this logically (mysqldump / mydumper) as this is a simple task to perform as long as you can connect to the database instance, so I wanted to approach physical backups using the very common xtrabackup tool. Additionally, we’re trying to think with containers here, so I wanted to make sure that not only would I be taking a backup of the Docker container MySQL instance, but I would do it with another Docker container running …