It could be as simple as calling from a shell in your app:
kubectl create namespace <your-namespace-name>
Essentially, kubectl talks to the kube-apiserver.
You can also directly call the kube-apiserver. This is an example to list the pods:
$ curl -k -H 'Authorization: Bearer <token>' \
https://$KUBERNETES_SERVICE_HOST:6443/api/<api-version>/namespaces/default/pods
More specifically to create a namespace:
$ curl -k -H -X POST -H 'Content-Type: application/json' \
-H 'Authorization: Bearer <token>' \
https://$KUBERNETES_SERVICE_HOST:6443/api/v1/namespaces/ -d '
{
"apiVersion": "v1",
"kind": "Namespace",
"metadata": {
"name": "mynewnamespace"
}
}'
In case you are wondering about the <token>
, it's a Kubernetes Secret typically belonging to a ServiceAccount and bound to a ClusterRole
that allows you to create namespaces.
You can create a Service Account like this:
$ kubectl create serviceaccount namespace-creator
Then you'll see the token like this (a token is automatically generated):
$ kubectl describe sa namespace-creator
Name: namespace-creator
Namespace: default
Labels: <none>
Annotations: <none>
Image pull secrets: <none>
Mountable secrets: namespace-creator-token-xxxxx
Tokens: namespace-creator-token-xxxxx
Events: <none>
Then you would get the secret:
$ kubectl describe secret namespace-creator-token-xxxxx
Name: namespace-creator-token-xxxx
Namespace: default
Labels: <none>
Annotations: kubernetes.io/service-account.name: namespace-creator
kubernetes.io/service-account.uid: <redacted>
Type: kubernetes.io/service-account-token
Data
====
ca.crt: 1025 bytes
namespace: 7 bytes
token: <REDACTED> <== This is the token you need for Authorization: Bearer
Your ClusterRole
should look something like this:
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: namespace-creator
rules:
- apiGroups: ["*"]
resources: ["namespaces"]
verbs: ["create"]
Then you would bind it like this:
$ kubectl create clusterrolebinding namespace-creator-binding --clusterrole=namespace-creator --serviceaccount=namespace-creator
When it comes to writing code you can use any HTTP client library in any language to call the same endpoints.
There are also libraries like the client-go library that takes care of the plumbing of connecting to a kube-apiserver.