Reconciler Guide

This guide describes how to enable the reconciler in Open Service Mesh (OSM).

How the reconciler works

The goal of building a reconciler in OSM is to ensure resources required for the correct operation of OSM’s control plane are in their desired state at all times. Resources that are installed as a part of OSM install and have the labels openservicemesh.io/reconcile: true and app.kubernetes.io/name: openservicemesh.io will be reconciled by the reconciler.

Note: The reconciler will not operate as desired if the lables openservicemesh.io/reconcile: true and app.kubernetes.io/name: openservicemesh.io are modified or deleted on the reconcilable resources.

An update or delete event on the reconcilable resources will trigger the reconciler and it will reconcile the resource back to its desired state. Only metadata changes (excluding a name change) will be permitted on the reconcilable resources.

Resources reconciled

The resources that OSM reconciles are:

  • CRDs : The CRDs installed/required by OSM CRDs for OSM will be reconciled. Since OSM manages the installation and upgrade of the CRDs it needs, OSM will also reconcile them to ensure that their spec, stored and served verions are always in the state that is required by OSM.

  • MutatingWebhookConfiguration : A MutatingWebhookConfiguration is deployed as a part of OSM’s control plane to enable automatic sidecar injection. As this is a very critical component for pods joining the mesh, OSM reconciles this resource.

  • ValidatingWebhookConfiguration : A ValidatingWebhookConfiguration is deployed as a part of OSM’s control plane to validate various mesh configurations. This resources validates configurations being applied to the mesh, hence OSM will reconcile this resource.

How to install OSM with the reconciler

To install OSM with the reconciler, use the below command:

  1. $ osm install --set osm.enableReconciler=true
  2. OSM installed successfully in namespace [osm-system] with mesh name [osm]