Keep shared config in sync across namespaces.

The annotation value is a namespace label selector. Replikate keeps a managed copy of the source in each matching namespace: a change to the source updates every copy, deleting the source or removing the annotation deletes the copies, and a newly labelled namespace is populated automatically.

Replikate never overwrites an object it does not manage. If a namespace already holds an unmanaged object of the same name, it is left alone and a Conflict event is emitted.

1. Install.

$ helm upgrade --install replikate charts/replikate \
    --namespace replikate --create-namespace \
    --set image.tag=v1.4.0

2. Create the source.

apiVersion: v1
kind: ConfigMap
metadata:
  name: shared-config
  namespace: default
  annotations:
    replikate.ubixsys.com/sync: "team=web"
data:
  LOG_LEVEL: "info"

$ kubectl apply -f shared-config.yaml

3. Opt a namespace in by labelling it.

$ kubectl label namespace some-namespace team=web
$ kubectl get configmap shared-config -n some-namespace

4. Change the source; the copy follows.

$ kubectl patch configmap shared-config -n default \
    --type merge -p '{"data":{"LOG_LEVEL":"debug"}}'
$ kubectl get configmap shared-config -n some-namespace -o jsonpath='{.data.LOG_LEVEL}'
debug

5. Stop replicating. Removing the annotation deletes every managed copy.

$ kubectl annotate configmap shared-config -n default replikate.ubixsys.com/sync-

Replikate also replicates Secrets, and can copy a source into other clusters, and into several namespaces on each (green:web,green:live), with the target-clusters annotation; see the Replikate page for the hub-and-spoke setup.

The manifests above, with a script that checks each step, are in ubixsys-manual-examples under examples/replikate/.