Loading manifests without namespace specified fails

[dpen2000]

Describe the bug
K3s fails to load manifests from /var/lib/rancher/k3s/server/manifests if they don't specify a namespace.

To Reproduce

1. Run k3s server in one terminal
2. Run nano /var/lib/rancher/k3s/server/manifests/deployment.yaml in another terminal
3. Paste ( from https://kubernetes.io/docs/tasks/run-application/run-stateless-application-deployment/ ):

apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 2 # tells deployment to run 2 pods matching the template
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80

4. Save
5. k3s logs in first terminal show error:

ERRO[2019-03-04T23:49:11.027423617Z] failed to process config: failed to process /var/lib/rancher/k3s/server/manifests/deployment.yaml: failed to create nginx-deployment apps/v1, Kind=Deployment for deployment: an empty namespace may not be set during creation

Expected behavior
K3s should assume default namespace and create deployment as per kubectl apply

[dpen2000]

@ibuildthecloud I've got k3s building myself now so happy to try to send a PR for this one.

[ibuildthecloud]

@dpen2000 I went ahead and tried to fix this while I was fixing another bug, but it's not heavily tested. Do you want to give v0.2.0-rc6 a try and see if its working now? It should assign the namespace to "default" for namespaced resources where the namespace is "".

[dpen2000]

@ibuildthecloud The example above works. As for helm charts, I tried:

apiVersion: k3s.cattle.io/v1
kind: HelmChart
metadata:
  name: redis
spec:
  chart: stable/redis

which doesn't work for me. I don't get any error output about it either. This doesn't either:

apiVersion: k3s.cattle.io/v1
kind: HelmChart
metadata:
  name: redis
  namespace: default
spec:
  chart: stable/redis

Only specifiying kube-system seems to work:

apiVersion: k3s.cattle.io/v1
kind: HelmChart
metadata:
  name: redis
  namespace: kube-system
spec:
  chart: stable/redis

Editing this chart to say default results in it creating job.batch/helm-delete-redis to delete redis from cluster.

[erikwilson]

Also verified that example nginx deployment works, created a new issue for Helm deployments.