Q: How can I access the events which triggered the Reconciliation?

In the v1.* version events were exposed to Reconciler (which was called ResourceController then). This included events (Create, Update) of the custom resource, but also events produced by Event Sources. After long discussions also with developers of golang version (controller-runtime), we decided to remove access to these events. We already advocated to not use events in the reconciliation logic, since events can be lost. Instead, reconcile all the resources on every execution of reconciliation. On first this might sound a little opinionated, but there is a sound agreement between the developers that this is the way to go.

Note that this is also consistent with Kubernetes level based reconciliation approach.

Q: Can I re-schedule a reconciliation, possibly with a specific delay?

Yes, this can be done using UpdateControl and DeleteControl , see:

  public UpdateControl<MyCustomResource> reconcile(
     EventSourceTestCustomResource resource, Context context) {
    return UpdateControl.patchStatus(resource).rescheduleAfter(10, TimeUnit.SECONDS);

without an update:

  public UpdateControl<MyCustomResource> reconcile(
     EventSourceTestCustomResource resource, Context context) {
    return UpdateControl.<MyCustomResource>noUpdate().rescheduleAfter(10, TimeUnit.SECONDS);

Although you might consider using EventSources, to handle reconciliation triggering in a smarter way.

Q: How can I run an operator without cluster scope rights?

By default, JOSDK requires access to CRs at cluster scope. You may not be granted such rights and you will see some error at startup that looks like:

io.fabric8.kubernetes.client.KubernetesClientException: Failure executing: GET at: https://kubernetes.local.svc/apis/mygroup/v1alpha1/mycr. Message: Forbidden! Configured service account doesn't have access. Service account may have been revoked. mycrs.mygroup is forbidden: User "system:serviceaccount:ns:sa" cannot list resource "mycrs" in API group "mygroup" at the cluster scope.

To restrict the operator to a set of namespaces, you may override which namespaces are watched by a reconciler at Reconciler-level configuration:

Operator operator;
Reconciler reconciler;
operator.register(reconciler, configOverrider ->

Note that configuring the watched namespaces can also be done using the @ControllerConfiguration annotation.

Furthermore, you may not be able to list CRDs at startup which is required when checkingCRDAndValidateLocalModel is true (false by default). To disable, set it to false at Operator-level configuration:

Operator operator = new Operator( override -> override.checkingCRDAndValidateLocalModel(false));

Q: How to fix sun.security.provider.certpath.SunCertPathBuilderException on Rancher Desktop and k3d/k3s Kubernetes

It’s a common issue when using k3d and the fabric8 client tries to connect to the cluster an exception is thrown:

Caused by: javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:131)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:352)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:295)

The cause is that fabric8 kubernetes client does not handle elliptical curve encryption by default. To fix this, add the following dependency on the classpath:


Last modified May 21, 2024: feat: docsy migration (#2352) (1bd712e0)