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CNF Deployment Using Operators

Overview

Operators are Kubernetes controllers that manage custom resources and automate application lifecycle tasks. When deploying CNFs (Cloud Native Network Functions) using operators, the test suite supports robust identification of resources created by operators, even when resources are created dynamically or indirectly.

Resource Identification Strategies

  1. Label-based Identification

    • The test suite fetches resources matching label selectors defined in cnf-testsuite.yml under workload_resource_labels.
    • After all deployments are installed, resources with these labels are identified and appended to the composite manifest (installed_cnf_files/common-manifest.yml).
    • This enables tests to reference resources reliably, regardless of when or how they are created by the operator.

  2. OwnerReference-based Identification

    • Many operators create workload resources (e.g., Deployments, Pods, ReplicaSets) with ownerReferences pointing to custom resources (CRDs) managed by the operator.
    • The test suite scans for resources owned by custom resources, using the ownerReferences field in Kubernetes metadata.
    • These owned resources are also appended to the composite manifest, ensuring that all relevant resources are tracked for testing.

Example: Operator Deployment

Suppose an operator creates Deployments for a custom resource (for example, PodSet) so the Pods are managed by those Deployments:

  • Labeled Deployments:

    • Deployments are created with labels such as cnf: my-operator.
    • The test suite will identify those workload resources using the label selectors and then inspect the Pods selected by the Deployment.

  • Owned Deployments:

    • Deployments are created with ownerReferences pointing to a custom resource (e.g., PodSet).
    • The test suite will identify those workload resources by traversing owner references from custom resources and then inspect the Pods selected by the Deployment.

How the Test Suite Handles Operator Resources

  • During installation, the suite waits for resources to become ready, using configurable timeouts.
  • After installation, it fetches label-identified and ownerReference-identified resources and adds them to the manifest.
  • Tests consume resources from the manifest, ensuring consistent and reliable test coverage even for dynamically created resources.

Configuration

  • Label Selectors:
    • Define label selectors in cnf-testsuite.yml under workload_resource_labels.
  • Timeouts:
    • Use the timeout CLI argument or CNF_TESTSUITE_LABEL_RESOURCE_SLEEP environment variable to control waiting behavior for resource identification.

Best Practices

  • Ensure operator sets meaningful labels or ownerReferences on the workload resources it creates.
  • Use unique labels for each CNF to avoid conflicts.
  • Review the composite manifest to verify all expected resources are included.
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