cmstate-injector-operator

Overview

cmstate-injector-operator is a Kubernetes operator that simplifies the management of ConfigMaps by dynamically creating them based on the specifications defined in Custom Resource Definitions (CRDs). The operator focuses on the interaction between CMTemplate and CMState CRDs, offering a streamlined approach to ConfigMap management in a Kubernetes cluster.

Features

• CMTemplate CRD: Define a template for ConfigMaps using the CMTemplate CRD. This includes specifying annotations for template replacement values.

• CMState CRD: Track the usage of ConfigMaps by Pods through the CMState CRD. Maintain an audience list to identify Pods utilizing the created ConfigMap.

• Reconcile Loop: The operator performs reconciliation for CMState and CMTemplate CRDs, ensuring that the ConfigMap state aligns with the desired specifications.

• Mutating Webhook: Triggered on Pod creation and deletion, the mutating webhook watches for a specific annotation, cache.spicedelver.me/cmtemplate, targeting a valid and created CMTemplate.

Getting Started

Prerequisites

• Kubernetes cluster
• kubectl configured to access the cluster

Only if modifying this operator by adding more controllers should you need this:

• operator-sdk installed

Installation

Operator Deployment

1. Clone the repository:

   git clone https://github.com/your-username/cmstate-injector-operator.git
   cd cmstate-injector-operator

2. Build and deploy the operator:

   make install
   make deploy

3. Verify the deployment:

   kubectl get pods -n <namespace>

Helm Chart Deployment

Alternatively, you can deploy the operator using the Helm chart located in the charts directory.

1. Change into the charts directory:

   cd charts

2. Install the Helm chart:

   helm install cmstate-injector-operator .

3. Verify the deployment:

   kubectl get pods -n <namespace>

Usage

1. Define a CMTemplate to specify the template for your ConfigMap:

    apiVersion: cache.spicedelver.me/v1alpha1
    kind: CMTemplate
    metadata:
        name: cmtemplate-example
    spec:
    template:
        annotationreplace:
            example-annotation: '{example-regex}'
        cmtemplate:
            config.ini: |
                name = {example-regex}
                write_to_example = true
            targetAnnotation: example-target-annotation

2. Create a CMState to track ConfigMap usage:

    apiVersion: cache.spicedelver.me/v1alpha1
    kind: CMState
    metadata:
        name: cmstate-example
        namespace: example
    spec:
        audience:
        - kind: Pod
            name: example
        cmtemplate: cmtemplate-example
        target: cmstate-example-configmap

3. Pods that reference the created ConfigMap should include the annotation:

   metadata:
     annotations:
       cache.spicedelver.me/cmtemplate: cmtemplate-example

Contributing

Contributions are welcome! Please check out our contribution guidelines for more details.

License

This project is licensed under the MIT License. See the LICENSE file for details.

Acknowledgments

• operator-sdk
• Kubernetes community

Contact

For any questions or feedback, please reach out to stephen@tollenaar.com.