Reflector

Reflector is a Kubernetes addon designed to monitor changes to resources (secrets and configmaps) and reflect changes to mirror resources in the same or other namespaces.

Supports amd64, arm and arm64

Extensions

Reflector includes a cert-manager extension used to automatically annotate created secrets and allow reflection. See the cert-manager extension usage below for more details.

Support

If you need help or found a bug, please feel free to open an Issue on GitHub (https://github.com/emberstack/kubernetes-reflector/issues).

You can also join our Slack workspace and talk to us:

Deployment

Reflector can be deployed either manually or using Helm (recommended).

Prerequisites

• Kubernetes 1.14+
• Helm 3 (if deployed using Helm)

Deployment using Helm

Use Helm to install the latest released chart:

$ helm repo add emberstack https://emberstack.github.io/helm-charts
$ helm repo update
$ helm upgrade --install reflector emberstack/reflector

You can customize the values of the helm deployment by using the following Values:

Parameter	Description	Default
nameOverride	Overrides release name	""
fullnameOverride	Overrides release fullname	""
image.repository	Container image repository	emberstack/kubernetes-reflector
image.tag	Container image tag	Same as chart version
image.pullPolicy	Container image pull policy	IfNotPresent
configuration.logging.minimumLevel	Logging minimum level	Information
rbac.enabled	Create and use RBAC resources	true
serviceAccount.create	Create ServiceAccount	true
serviceAccount.name	ServiceAccount name	release name
livenessProbe.initialDelaySeconds	livenessProbe initial delay	5
livenessProbe.periodSeconds	livenessProbe period	10
readinessProbe.initialDelaySeconds	readinessProbe initial delay	5
readinessProbe.periodSeconds	readinessProbe period	10
resources	Resource limits	{}
nodeSelector	Node labels for pod assignment	{}
tolerations	Toleration labels for pod assignment	[]
affinity	Node affinity for pod assignment	{}

Find us on Helm Hub

Manual deployment

Each release (found on the Releases GitHub page) contains the manual deployment file (reflector.yaml).

$ kubectl apply -f https://github.com/emberstack/kubernetes-reflector/releases/latest/download/reflector.yaml

Usage

1. Annotate the source secret or configmap

• Add reflector.v1.k8s.emberstack.com/reflection-allowed: "true" to the resource annotations to permit reflection to mirrors.
• Add reflector.v1.k8s.emberstack.com/reflection-allowed-namespaces: "<list>" to the resource annotations to permit reflection from only the list of comma separated namespaces or regular expressions. If this annotation is omitted or is empty, all namespaces are allowed.

Automatic mirror creation:

Reflector can create mirrors with the same name in other namespaces automatically. The following annotations control if and how the mirrors are created:

• Add reflector.v1.k8s.emberstack.com/reflection-auto-enabled: "true" to the resource annotations to automatically create mirrors in other namespaces. Note: Requires reflector.v1.k8s.emberstack.com/reflection-allowed to be true since mirrors need to able to reflect the source.
• Add reflector.v1.k8s.emberstack.com/reflection-auto-namespaces: "<list>" to the resource annotations specify in which namespaces to automatically create mirrors. If this annotation is omitted or is empty, all namespaces are allowed. Note: Namespaces in this list will also be checked by reflector.v1.k8s.emberstack.com/reflection-allowed-namespaces since mirrors need to be in namespaces from where reflection is permitted.

Important: If the source is deleted, automatic mirrors are deleted. Also if either reflection or automirroring is turned off or the automatic mirror's namespace is no longer a valid match for the allowed namespaces, the automatic mirror is deleted.

Important: Reflector will skip any conflicting resource when creating auto-mirrors. If there is already a resource with the source's name in a namespace where an automatic mirror is to be created, that namespace is skipped and logged as a warning.

Example source secret:

apiVersion: v1
kind: Secret
metadata:
 name: source-secret
 annotations:
   reflector.v1.k8s.emberstack.com/reflection-allowed: "true"
   reflector.v1.k8s.emberstack.com/reflection-allowed-namespaces: "namespace-1,namespace-2,namespace-[0-9]*"
data:
 ...

Example source configmap:

apiVersion: v1
kind: ConfigMap
metadata:
 name: source-config-map
 annotations:
   reflector.v1.k8s.emberstack.com/reflection-allowed: "true"
   reflector.v1.k8s.emberstack.com/reflection-allowed-namespaces: "namespace-1,namespace-2,namespace-[0-9]*"
data:
 ...

2. Annotate the mirror secret or configmap

• Add reflector.v1.k8s.emberstack.com/reflects: "<source namespace>/<source name>" to the mirror object. The value of the annotation is the full name of the source object in namespace/name format.

Note: Add reflector.v1.k8s.emberstack.com/reflected-version: "" to the resource annotations when doing any manual changes to the mirror (for example when deploying with helm or re-applying the deployment script). This will reset the reflected version of the mirror.

Example mirror secret:

apiVersion: v1
kind: Secret
metadata:
 name: mirror-secret
 annotations:
   reflector.v1.k8s.emberstack.com/reflects: "default/source-secret"
data:
 ...

Example mirror configmap:

apiVersion: v1
kind: ConfigMap
metadata:
 name: mirror-config-map
 annotations:
   reflector.v1.k8s.emberstack.com/reflects: "default/source-config-map"
data:
 ...

3. Done!

Reflector will monitor any changes done to the source objects and copy the following fields:

• data for secrets
• data and binaryData for configmaps Reflector keeps track of what was copied by annotating mirrors with the source object version.

---

cert-manager extension

Supported cert-manager version: 0.11.0 or higher.

Reflector can automatically annotate secrets created by cert-manager by annotating the Certificate object. This allows for issued certificates (example: wildcard certificates) to be reused in other namespaces and permit automatic updates of mirrors on certificate renewal.

• Add reflector.v1.k8s.emberstack.com/secret-reflection-allowed to the certificate annotations. Reflector will automatically annotate the resulting secret with reflector.v1.k8s.emberstack.com/reflection-allowed.
• Add reflector.v1.k8s.emberstack.com/secret-reflection-allowed-namespaces: "<list>" to the certificate annotations. Reflector will automatically annotate the resulting secret with reflector.v1.k8s.emberstack.com/reflection-allowed-namespaces.
• Add reflector.v1.k8s.emberstack.com/secret-reflection-auto-enabled: "true" to the certificate annotations. Reflector will automatically annotate the resulting secret with reflector.v1.k8s.emberstack.com/reflection-auto-enabled.
• Add reflector.v1.k8s.emberstack.com/secret-reflection-auto-namespaces: "<list>" to the certificate annotations. Reflector will automatically annotate the resulting secret with reflector.v1.k8s.emberstack.com/reflection-auto-namespaces.

In the following example, the generated secret certificate-secret will be annotated with the reflector.v1.k8s.emberstack.com/reflection-allowed and reflector.v1.k8s.emberstack.com/reflection-allowed-namespaces based on the certificate annotations.

apiVersion: cert-manager.io/v1alpha1
kind: Certificate
metadata:  
  name: some-certificate
  annotations:
    reflector.v1.k8s.emberstack.com/secret-reflection-allowed: "true"
    reflector.v1.k8s.emberstack.com/secret-reflection-allowed-namespaces: "namespace-1,namespace-2,namespace-[0-9]*"
spec:
  secretName: certificate-secret
  ...

Example mirror certificate secret:

apiVersion: v1
kind: Secret
metadata:
  name: mirror-certificate-secret
  annotations:
    reflector.v1.k8s.emberstack.com/reflects: "default/certificate-secret"
data:
  ...