The Declarative Model and the Desired State

Declarative model

The declarative model and desired state are at the core of how Kubernetes operates. They operate on three basic principles:

• Observed state

• Desired state

• Reconciliation

Observed state is what we have, desired state is what we want, and reconciliation is the process of keeping observed state in sync with desired state.

Note: We use the terms actual state, current state, and observed state to mean the same thing — the most up-to-date view of the cluster.

Working of the declarative model

In Kubernetes, the declarative model works like this: