Copy Secrets from one Namespace to another on Kubernetes

This container/NodeJS Script copies secrets from one source namespace to another one.

This can be used for example if secrets are managed centrally in a namespace but the clients needing the secrets live in another one.

Beware: For more advanced use cases a 'real' secret management system as Vault is highly recommended!

Installation

1. Set the NAMESPACE environment variable where k8s-copy-secrets should watch for secrets.

As a node script (for Development)

1. Ensure that kubectl is working and you can access the Kubernetes Cluster.

yarn
yarn run start

As a docker container

1. Setup the KUBECONFIG (in dev: $HOME/.kube/config, in prod: mounted e.g. from a secret)

docker build -t k8s-copy-secrets .
docker run -e NAMESPACE=[YOUR-NAMESPACE] \
  -e KUBECONFIG=/etc/kubeconfig \
  -v [PATH-TO-YOUR-KUBECONFIG]:/etc/kubeconfig \
   k8s-copy-secrets

Usage

Label the secret that should be copied with the target namespace. Example:

apiVersion: v1
kind: Secret
metadata:
  name: testsecret
  labels:
    k8s-copy-secret/target-namespace: foo # <---- This line is important
    # Use following label to copy additional secrets to the
    # target namespace. E.g. if you need to copy the CA cert belonging
    # to your private key
    #k8s-copy-secret/additional-secrets: testsecret2
type: Opaque
data:
  foo: YmFyCg==
  bar: YmFuYW5hCg==

1. On startup, k8s-copy-secret will attempt to copy all secrets with the label k8s-copy-secret/target-namespace to the target namespace.
2. When a new secret with that label is created while k8s-copy-secret is running, it will attempt to copy that secret.
3. When a secret is modified (with that label) while k8s-copy-secret is running, it will copy the secret in the target namespace
4. When a secret is deleted (with that label) while k8s-copy-secret is running, it will attempt delete the secret in the target namespace

k8s-copy-secret will never override secrets it did not copy from the watched namespace! This is determined by the label k8s-copy-secret/source-namespace in the target secret. If it does not exist or does not match the watched namespace, the secret is ignored.

Gotchas

• When a secret is deleted while no k8s-copy-secrets instance is running, the secret will not be deleted in the target namespace.
• If two k8s-copy-secrets instances are running in parallel watching the same namespace one of them will throw errors because the other instance was faster. Be careful
• k8s-copy-secrets can currently monitor only one namespace

License

k8s-copy-secrets is licensed under the Apache License, Version 2.0