Object Reconciler

The Object Reconciler (package pkg/reconciler) is the workhorse — the core, the low-level engine — of component-operator-runtime. Its main type, Reconciler, takes a set of provided resource manifests and maintains them in a target Kubernetes cluster.

Everything the higher-level controller-runtime integration does eventually funnels down into this engine. You can also use it directly, without the component abstraction, whenever you need programmatic, ordered, drift-aware management of a set of Kubernetes objects.

What it does

Given a list of manifests and a persisted inventory, the reconciler will:

• create objects that do not exist yet,
• update objects that have drifted from their desired manifest,
• remove objects that are no longer part of the desired set,
• order all of this into apply and delete waves,
• track everything it manages in the inventory,
• protect extension types (CRDs, aggregated APIs) from unsafe deletion.

How it is driven

The reconciler is level-based and idempotent. Its Apply() and Delete() methods are designed to be called repeatedly: each call moves the cluster a step closer to the desired state and reports — via a boolean return value — whether the target state has been fully reached. The caller persists the inventory between invocations and re-invokes until the operation is complete.

Topics

• Overview — the Reconciler type, its constructor, options, and the Apply / Delete / IsDeletionAllowed methods.
• Drift Detection — how object digests and the reapply interval keep the cluster in sync.
• Apply and Delete Waves — ordering the reconciliation of dependent objects.
• Completion — ephemeral objects and the purge order.
• Policies — adoption (ownership), reconcile, update, delete, and missing-namespaces policies.
• Managed Types — special handling of CRDs and APIService types, and the stuck-finalizer safeguard.
• Dependent Objects — the full list of annotations supported on dependent objects.
• Enhanced Status Detection — why vanilla kstatus is not enough, and how it is improved.
• The Inventory — anatomy and function of the inventory.
• Client and Scheme — requirements on the client and scheme passed to the reconciler.