If you have a series of yaml files without namespaces in their metadata, and add one and reapply the files, an entirely new series of resources will be created in the new namespace. Moving a series of resources, then, involves spinning up a new set of resources, migrating the data across, and taking down the old set.

Create a new namespace:

apiVersion: v1
kind: Namespace
  name: test
    name: test

It’s convenient to also create a context for your namespace:

kubectl config set-context test --user=USERNAME --cluster CLUSTERNAME --namespace=test

Check which resources are and are not namespaced


kubectl api-resources --namespaced=false

you can see that the common resources that aren’t namespace are Namespaces, Nodes and PersistentVolumes (though Claims are). In particular, ServiceAccounts are namespaced! This lead to having to make a change to our eksctl-managed file and running eksctl create iamserviceaccount again (having duplicated the service account but with a namespace this time).

Apply the new, namespaced resources

Add a metadata.namespace entry to each resource, and apply. This will create a series of brand new resources in the new namespace, in addition to the old resources in the old namespace. Wait until they all come up. If any errors, you can check on the replica sets kubectl describe rs NAME for more detail.

Moving the data across

A PVC in the new namespace will have a new PV associated to it. You could move the PV across, possibly, by switching the persistentVolumeReclaimPolicy to Retain, deleting the original claim, then setting the volume of the new PVC. An alternative would be to copy the data from one volume to the other. The latter allows you to keep both deployments up until you’re ready to switch over, but could take a long time if there’s a lot of data.

I used mongodump / mongorestore to dump / restore the mongo database, taking the basic command from StackExchange:

kubectl port-forward deployment/mongo --namespace default 27017:27017 &
docker run --rm -v $(pwd):/workdir/ -w /workdir/ --network host mongo:4.4.4 mongodump --out /workdir/dump/

followed by

kubectl port-forward deployment/mongo --namespace test 27017:27017 &
docker run --rm -v $(pwd):/workdir/ -w /workdir/ --network host mongo:4.4.4 mongorestore /workdir/dump

Changing the DNS to point to the new servers

After confirming that the data was moved, I changed the DNS records to point to the new load balancers visible on kubectl get svc.

Deleting the old resources

I switched back to the old namespace (very important), and then a series of kubectl delete X commands cleaned the old resources up. I did these manually, as I tend to do while deleting things, checking the timestamps to confirm I was deleting the right things.