The aim of Percona Kubernetes Operator for Percona XtraDB Cluster is to be a special type of controller introduced to simplify complex deployments. The Operator extends the Kubernetes API with custom resources. The Operator solution is using Percona XtraDB Cluster (PXC) behind the hood to provide a highly available, resilient, and scalable MySQL service in the Kubernetes space. 

This solution comes with all the advantages/disadvantages provided by Kubernetes, plus some advantages of its own like the capacity to scale reads on the nodes that are not Primary.

Of course, there are some limitations like the way PXC handles DDLs, which may impact the service, but there is always a cost to pay to get something, expecting to have it all for free is unreasonable.     

In this context, we need to …

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 …