Object pruning utility for Go-based Operators

The operator-lib pruning utility lets Go-based Operators clean up, or prune, objects when they are no longer needed. Operator authors can also use the utility to create custom hooks and strategies.

About the operator-lib pruning utility

Objects, such as jobs or pods, are created as a normal part of the Operator life cycle. If the cluster administrator or the Operator does not remove these object, they can stay in the cluster and consume resources.

Previously, the following options were available for pruning unnecessary objects:

• Operator authors had to create a unique pruning solution for their Operators.

• Cluster administrators had to clean up objects on their own.

The operator-lib pruning utility removes objects from a Kubernetes cluster for a given namespace. The library was added in version 0.9.0 of the operator-lib library as part of the Operator Framework.

Pruning utility configuration

The operator-lib pruning utility is written in Go and includes common pruning strategies for Go-based Operators.

Example configuration

cfg = Config{
        log:           logf.Log.WithName("prune"),
        DryRun:        false,
        Clientset:     client,
        LabelSelector: "app=<operator_name>",
        Resources: []schema.GroupVersionKind{
                {Group: "", Version: "", Kind: PodKind},
        },
        Namespaces: []string{"<operator_namespace>"},
        Strategy: StrategyConfig{
                Mode:            MaxCountStrategy,
                MaxCountSetting: 1,
        },
        PreDeleteHook: myhook,
}

The pruning utility configuration file defines pruning actions by using the following fields:

Pruning execution

You can call the pruning action by running the execute function on the pruning configuration.

err := cfg.Execute(ctx)

You can also call a pruning action by using a cron package or by calling the pruning utility with a triggering event.