statefulset-pvc-cleaner

Overview

This project is a Kubernetes controller to handle garbage collection of PersistentVolumeClaims created by StatefulSets.

This controller is simpler and is not intended to replace the Kubernetes StatefulSet PVC Auto-Deletion feature but rather to provide a PersistentVolumeClaim garbage collection mechanism on clusters that do not yet have this feature.

Installation

Helm

Follow statefulset-pvc-cleaner documentation for Helm deployment here.

Usage

In order to handle the removal of PersisPersistentVolumeClaims from a StatefulSet when it is deleted, this controller simply updates them to set an owner reference to the StatefulSet (to learn more about garbage collection of kubernetes resources, refer to this documentation).

To do this, it relies on two annotations to put on the PersisPersistentVolumeClaims.

• statefulset-pvc-cleaner.quortex.io/retention: Set this annotation value to delete to enable garbage collection on this PersisPersistentVolumeClaim.
• statefulset-pvc-cleaner.quortex.io/statefulset: Specify the name of the PersisPersistentVolumeClaim's StatefulSet as the value of this annotation. This is required by the controller to avoid heavy processing in order to deduce it.

Once the owner reference is defined, we have no way of knowing if the owner reference of the StatefulSet is ours alone (another controller could be responsible for similar behavior...), so we don't proceed to remove the reference, even if the annotations changes.

An example of StatefulSet configuration, in this case, only xxx PersisPersistentVolumeClaim will be garbage collected on StatefulSet's deletion.

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: nginx:latest
          ports:
            - containerPort: 80
              name: web
          volumeMounts:
            - name: www
              mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
    - metadata:
        name: www
      spec:
        accessModes: ["ReadWriteOnce"]
        resources:
          requests:
            storage: 1Gi
    - metadata:
        name: xxx
        annotations:
          statefulset-pvc-cleaner.quortex.io/retention: delete
          statefulset-pvc-cleaner.quortex.io/statefulset: web
      spec:
        accessModes: ["ReadWriteOnce"]
        resources:
          requests:
            storage: 1Gi

Configuration

Optional args

The statefulset-pvc-cleaner container takes the following flags as argument.

Key	Description	Default
metrics-bind-address	The address the metric endpoint binds to.	:8080
health-probe-bind-address	The address the probe endpoint binds to.	:8081
leader-elect	Enable leader election for controller manager. Enabling this will ensure there is only one active controller manager.	false
zap-devel	Whether to enable development logs.	false
zap-encoder	Logs encoding (one of json or console)	Defaults to console when zap-devel is true and json otherwise.
zap-log-level	Level to configure the verbosity of logging. Can be one of debug, info, error, or any integer value > 0 which corresponds to custom debug levels of increasing verbosity).	Defaults to debug when zap-devel is true and info otherwise.
zap-stacktrace-level	Level at and above which stacktraces are captured (one of info, error or panic).	Defaults to warn when zap-devel is true and error otherwise.
zap-time-encoding	Logs time encoding (one of epoch, millis, nano, iso8601, rfc3339 or rfc3339nano).	epoch

License

Distributed under the Apache 2.0 License. See LICENSE for more information.

Contributing

To contribute to this project, please first consult the contribution rules guide.

Got a question? File a GitHub issue.