Kubernetes has been a big trend for a while now, particularly well-suited for microservices. Running your main databases on Kubernetes is probably NOT what you are looking for. However, there’s a niche market for them. My colleague Stephen Thorn did a great job explaining this in The Criticality of a Kubernetes Operator for Databases. If you are considering running your database on Kubernetes, have a look at it first. And, if after reading it you start wondering how the Operator works, Stephen also wrote an Introduction to Percona Kubernetes Operator for Percona XtraDB Cluster (PXC), which presents the Kubernetes architecture and how the Percona Operator simplifies the deployment of a …

Galera replication technology, a key component of Percona XtraDB Cluster, suffered from a remote code execution vulnerability. Percona has been working with the vendor since early September on this issue and has made releases available to address the problem.

Applicability

A malicious party with access to the WSREP service port (4567/TCP) as well as prerequisite knowledge of the configuration of the Galera cluster name is required in order to exploit this vulnerability, which leads to remote code execution via the WSREP protocol. 

Fixes are available in Percona XtraDB Cluster versions:

>= 8.0.20-11.2

>= …

Schema changes are the big challenges in Galera replication. So, it is recommended to understand the schema changes operation for everyone who uses the Percona XtraDB Cluster (PXB)/Galera clusters. In this blog, I am going to explain the operation and impact of the various schema changes methods used in the PXB/Galera cluster.

• Schema changes with “wsrep_OSU_method = TOI”
• Schema changes with “wsrep_OSU_method = RSU”
• Schema changes with “ONLINE ALGORITHMS”
• Schema changes with “pt-osc”
• Schema changes with “gh-ost”

For testing:

• I have configured the 3-node Percona Xtradb Cluster (8.0.19).
• Executing read/write load using the sysbench.

mysql> select @@wsrep_cluster_address\G
*************************** 1. row …

I got this question on the “How to Avoid Pitfalls in Schema Upgrade with Percona XtraDB Cluster (PXC)” webinar and wanted to answer it in a separate post.

Will RSU have an effect on GTID consistency if replication PXC cluster to another cluster?

Answer for this: yes and no.

Galera assigns its own GTID for the operations, replicated to all nodes of the cluster. Such operations include DML (

INSERT/UPDATE/DELETE

 ) on InnoDB tables and DDL commands, executed with default TOI method. You can find more details on how GTIDs work in the Percona XtraDB Cluster in this blog post.

However, DDL commands, executed with RSU method, are …

On July 21, 2020, Percona delivered an updated version of our Percona Kubernetes Operator for Percona XtraDB Cluster (PXC) focused on easing deployment and operations management of a clustered MySQL environment. Included in the Percona Distribution for MySQL, our Operator is based on the best practices for MySQL cluster configuration and setup in Kubernetes. This update adds a variety of important new features including:

Smart Update to Safely and Reliably Upgrade your PXC Environment Automatically
We implemented a new update strategy called Smart Update. Smart Update is aware of the context of your environment and minimizes the number of failover events that need to occur to fully upgrade a …

You got yourself a Kubernetes cluster and are now testing our Percona Kubernetes Operator for Percona XtraDB Cluster. Everything is working great and you decided that you want to increase the number of Percona XtraDB Cluster (PXC) pods from the default 3, to let’s say, 5 pods.

It’s just a matter of running the following command:

kubectl patch pxc cluster1 --type='json' -p='[{"op": "replace", "path": "/spec/pxc/size", "value": 5 }]'

Good, you run the command without issues and now you will have 5 pxc pods! Right? Let’s check out how the pods are being replicated:

kubectl get pods | grep pxc
cluster1-pxc-0                                     1/1     Running   0          25m
cluster1-pxc-1                                     1/1     Running   0          23m
cluster1-pxc-2                                     1/1     Running …

The Percona Kubernetes Operator for Percona XtraDB Cluster(PXC) comes with ProxySQL as part of the deal. And to be honest, the behavior of ProxySQL is pretty much the same as in a regular non-k8s deployment of it. So why bother to write a blog about it? Because what happens around ProxySQL in the context of the operator is actually interesting.

ProxySQL is deployed on its own POD (that can be scaled as well as the PXC Pods can). Each ProxySQL Pod has its own ProxySQL Container and a sidecar container. If you are curious, you can find out which node holds the pod by running

kubectl describe pod cluster1-proxysql-0 | grep Node:
Node: ip-192-168-37-111.ec2.internal/192.168.37.111

Login into and ask for the running containers. You will see something like this:

[root@ip-192-168-37-111 ~]# docker ps | grep -i proxysql …

In real life, there are frequent cases where getting a running application to work correctly is strongly dependent on consistent write/read operations. This is no issue when using a single data node as a provider, but it becomes more concerning and challenging when adding additional nodes for high availability and/or read scaling. 

In the MySQL dimension, I have already described it here in my blog Dirty Reads in High Availability Solution.

We go from the most loosely-coupled database clusters with primary-replica async replication, to the fully tightly-coupled database clusters with NDB Cluster (MySQL/Oracle).

Adding components like ProxySQL to the architecture can, from one side, help in improving high availability, and from the other, it can amplify and randomize the negative effect of …

Long months of the pandemic lockdown have brought to life many great online events enabling the MySQL community to get together and stay informed about the very recent developments and innovations available to MySQL users. It isn’t over yet! Next Thursday, June 4th, Percona & ProxySQL are co-hosting the ProxySQL Tech Talks with Percona virtual meetup covering ProxySQL, MySQL and Percona XtraDB Cluster.

The attendees are invited to participate in the two-hour deep-dive event with plenty of time for questions and answers (we will have two 40-minute sessions + 20 minutes allocated for Q&A). Get prepared, come with your burning questions and true war stories – we’ll have our speakers answer and comment on them! And here come the speakers:

• René Cannaò, ProxySQL author and CEO of ProxySQL …

Percona has enforced stronger security in Percona XtraDB Cluster (PXC) 8, but this requires some attention during the rollout of the new server version, so let see the why and what.

In PXC there are two different kinds of traffic: client-server exchange (ie: application traffic), and replication traffic. The latter refers to any SST/IST, write-set, and other service messages the nodes exchange.

In PXC 5.7 it is possible to activate SSL encryption by enabling the variable pxc-encrypt-cluster-traffic by following the instructions.

In PXC 8, we choose to enable encryption by default on all replication traffic, to have the highest out-of-box security enforcement.

While this is an obvious …