How to override a namespace override

This functionality doesn't exist in Kustomize yet. There's an open issue addressing this, but no open PRs at the time of this writing.

The quickest solution here is to remove the namespace setting in the dev/kustomize.yaml and hand-set the namespace in all resources in dev.

Another option, shamelessly copied from the issue I cited earlier, is to create a transformer to get around this:

#!/usr/bin/env /usr/bin/python3

import sys
import yaml

with open(sys.argv[1], "r") as stream:
    try:
        data = yaml.safe_load(stream)
    except yaml.YAMLError as exc:
        print("Error parsing NamespaceTransformer input", file=sys.stderr)

# See kubectl api-resources --namespaced=false
denylist = [
    "ComponentStatus",
    "Namespace",
    "Node",
    "PersistentVolume",
    "MutatingWebhookConfiguration",
    "ValidatingWebhookConfiguration",
    "CustomResourceDefinition",
    "APIService",
    "MeshPolicy",
    "TokenReview",
    "SelfSubjectAccessReview",
    "SelfSubjectRulesReview",
    "SubjectAccessReview",
    "CertificateSigningRequest",
    "ClusterIssuer",
    "BGPConfiguration",
    "ClusterInformation",
    "FelixConfiguration",
    "GlobalBGPConfig",
    "GlobalFelixConfig",
    "GlobalNetworkPolicy",
    "GlobalNetworkSet",
    "HostEndpoint",
    "IPPool",
    "PodSecurityPolicy",
    "NodeMetrics",
    "PodSecurityPolicy",
    "ClusterRoleBinding",
    "ClusterRole",
    "ClusterRbacConfig",
    "PriorityClass",
    "StorageClass",
    "VolumeAttachment",
]

try:
    for yaml_input in yaml.safe_load_all(sys.stdin):
        if yaml_input['kind'] not in denylist:
            if "namespace" not in yaml_input["metadata"]:
                yaml_input["metadata"]["namespace"] = data["namespace"]
        print("---")
        print(yaml.dump(yaml_input, default_flow_style=False))
except yaml.YAMLError as exc:
    print("Error parsing YAML input\n\n%s\n\n" % input, file=sys.stderr)

Unfortunately it is not possible, the namespace override in kustomization assume all resources should belong to the same namespace.

Your alternative are:

• Create separate kustomization for resources that does not belong to the same namespace.
• Deploy resources that does not need kustomization by using kubectl apply -f .
• Use alternative replacement approach like suggested by Eric staples.

I generally create one kustomization per set of resources, that are deployed together in a namespace to make the kustomization simple and independent from any other resources.