Seamless MySQL 5.7 to 8.0 Migration on Kubernetes: Avoid Common Pitfalls (Part 3)

Introduction

In our ongoing migration series, we’re now diving into a critical phase: upgrading MySQL 5.7 to 8.0 within a Kubernetes (k8s) environment. Whether you're managing a small database or overseeing large-scale deployments, understanding the nuances of this process is key to avoiding costly errors.

Main Content

Our test environment involves a k8s cluster with a stateful MySQL 5.7 deployment. The data is stored in a persistent volume, just under 10GB. Given the constraints of our environment, using an in-place upgrade method isn't viable. Instead, we'll explore a safer and more reliable approach that minimizes the risk of data corruption.

Upgrading MySQL in a Kubernetes environment isn't as straightforward as updating the Docker image tag. A simple tag change from

public.ecr.aws/docker/library/mysql:5.7.x         

to

public.ecr.aws/docker/library/mysql:8.0.x        

can lead to severe table corruption, as shown in the following common errors:

(I'll cover how to solve this problem in my next article.)

[MY-013139] [Server] Cannot load from mysql.tables_priv. The table is probably corrupted!
[MY-013139] [Server] Cannot load from mysql.tables_priv. The table is probably corrupted!
[MY-013139] [Server] Cannot load from mysql.columns_priv. The table is probably corrupted!
[MY-013139] [Server] Cannot load from mysql.procs_priv. The table is probably corrupted!
[MY-013139] [Server] Cannot load from mysql.procs_priv. The table is probably corrupted!
        

For databases under 10GB, the safest and easiest migration strategy involves dumping the MySQL 5.7 database and restoring it in MySQL 8.0. This approach ensures data integrity and smooth transition, bypassing potential pitfalls that could arise from a direct in-place upgrade.

Curious if there's a more efficient method for managing MySQL upgrades within a Kubernetes environment, especially for minor versions? You're in luck! The solution lies in leveraging Kubernetes operators. I'll leave you with a powerful tool to explore: k8s MySQL Operator. Dive in and discover how it can streamline your database management.

Conclusion

Kubernetes shines with stateless applications, but it requires extra caution with stateful sets like MySQL. Have you faced challenges in your MySQL upgrades? Share your experiences or questions in the comments below—I’d love to hear from you!