Is there any benefit in using relational databases on K8s?

General Discussions
1

As far I as I understand K8s allows us to implement relatively easily horizontal scaling, deployment rollback and rolling deployments.

However, the moment our application uses a relational database these benefits seem to vaporize:

  1. Relational databases do not scale horizontally.
  2. Having explicit schema implies no rollback in a general case.
    • Rollback is hard If the DB schema changes are not backwards compatible
  3. Rolling deployments may mean having two versions of the code talk to one version of the schema - can be problematic in a general case.
    • New changes must be compatible with the old DB schema.

Am I missing anything? If I am right and we cannot take advantage of horizontal scaling, deployment rollbacks and rolling deployments (in a general case), what other reasons are there to use K8s?

Your thoughts are very much appreciated and welcome.

2
  1. Traditional RDBMSs don’t allow scaling. They allow read replicas at most. So you need to use distributed database like YugabyteDB.

2 and 3 are are problems with or without kubernetes.

For 2 - You have to look at backup / restoration, point in time recovery, etc.
For 3 - You breaking schema changes should be done in multiple steps
V1 App + V1 DB
V1.1 + V1/V1.1 DB
V1.1 + V1.1 DB
V1.2 + v1.1/V1.2 DB
V1.2 + v1.2 DB

Discloser: I work for Yugbayte