kubernetes unable to delete namespace

Resolving the problem

Run the following command to view the namespaces that are stuck in the Terminating state:

 kubectl get namespaces

Select a terminating namespace and view the contents of the namespace to find out the finalizer. Run the following command:

 kubectl get namespace <terminating-namespace> -o yaml

Your YAML contents might resemble the following output:

 apiVersion: v1
 kind: Namespace
 metadata:
   creationTimestamp: 2018-11-19T18:48:30Z
   deletionTimestamp: 2018-11-19T18:59:36Z
   name: <terminating-namespace>
   resourceVersion: "1385077"
   selfLink: /api/v1/namespaces/<terminating-namespace>
   uid: b50c9ea4-ec2b-11e8-a0be-fa163eeb47a5
 spec:
   finalizers:
   - kubernetes
 status:
   phase: Terminating

Run the following command to create a temporary JSON file:

 kubectl get namespace <terminating-namespace> -o json >tmp.json

Edit your tmp.json file. Remove the kubernetes value from the finalizers field and save the file.

Your tmp.json file might resemble the following output:

  {
      "apiVersion": "v1",
      "kind": "Namespace",
      "metadata": {
          "creationTimestamp": "2018-11-19T18:48:30Z",
          "deletionTimestamp": "2018-11-19T18:59:36Z",
          "name": "<terminating-namespace>",
          "resourceVersion": "1385077",
          "selfLink": "/api/v1/namespaces/<terminating-namespace>",
          "uid": "b50c9ea4-ec2b-11e8-a0be-fa163eeb47a5"
      },
      "spec": {
         "finalizers": 
      },
      "status": {
          "phase": "Terminating"
      }
  }

To set a temporary proxy IP and port, run the following command. Be sure to keep your terminal window open until you delete the stuck namespace:

 kubectl proxy

Your proxy IP and port might resemble the following output:

 Starting to serve on 127.0.0.1:8001

From a new terminal window, make an API call with your temporary proxy IP and port:

 curl -k -H "Content-Type: application/json" -X PUT --data-binary @tmp.json http://127.0.0.1:8001/api/v1/namespaces/<terminating-namespace>/finalize

Your output might resemble the following content:

 {
   "kind": "Namespace",
   "apiVersion": "v1",
   "metadata": {
     "name": "<terminating-namespace>",
     "selfLink": "/api/v1/namespaces/<terminating-namespace>/finalize",
     "uid": "b50c9ea4-ec2b-11e8-a0be-fa163eeb47a5",
     "resourceVersion": "1602981",
     "creationTimestamp": "2018-11-19T18:48:30Z",
     "deletionTimestamp": "2018-11-19T18:59:36Z"
   },
   "spec": {

   },
   "status": {
     "phase": "Terminating"
   }
}

1. Note: The finalizer parameter is removed.

Verify that the terminating namespace is removed, run the following command:

 kubectl get namespaces

Continue to follow the steps for other namespaces that are stuck in the Terminating state.