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Tenant

This folder provides a set of CRDs used to manage tenant resources in a Kubernetes cluster.

Overview

A cluster admin primarily leverages a tenant admin namespace to create, and thus manage all tenant related API objects including tenant namespaces (not directly though), arbitrary customized CRDs and policy objects like RBAC. This makes the tenant concept fully extensible instead of limiting the types of tenant objects specifically in TenantSpec. Basically, the tenant admin namespace name is specified in Tenant CR and tenant controller simply creates the namespace and configure the cluster RBAC rules for tenant admins to access various tenant related objects which are created on-demand (not implmented yet).

The most common tenant objects are tenant namespace CRs which encapsulate the configurations of tenant namespaces including name and RBAC rules etc. Tenant namespace controller does actual namespace creation for tenant users to use. The primary reason why we introduce tenant namespace CRD is that now tenant namespace creation can be RBAC permissioned, and tenant admins can do kubectl get tenantnamespace -n <tenant admin namespace> to list all the tenant namespaces. Otherwise had K8s namespace list API been used, all namespaces in the cluster would be exposed to tenant admins. Tenant admin can do self-service namespace creation via creating tenant namespace CR or even import existing namespace to tenant management system.

Getting Started

Install CRDs

kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/multi-tenancy/master/tenant/config/crds/tenancy_v1alpha1_tenant.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/multi-tenancy/master/tenant/config/crds/tenancy_v1alpha1_tenantnamespace.yaml

Install tenant-controller-managers

kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/multi-tenancy/master/tenant/config/manager/all_in_one.yaml

Basic Usage

As a cluster admin, use the following cmd to create a tenant CR. A tenant admin namespace tenant1admin will be created.

kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/multi-tenancy/master/tenant/config/samples/tenancy_v1alpha1_tenant.yaml

Create a testing service account, say t1-admin1 in any namespace, to mimic a tenant admin. (This script helps to create SA with corresponding KubeConfig file)

Then you can edit the tenant CR and add t1-admin1 to the tenantAdmins list

kubectl edit tenant tenant-sample

apiVersion: tenancy.x-k8s.io/v1alpha1
kind: Tenant
metadata:
  labels:
    controller-tools.k8s.io: "1.0"
  name: tenant-sample
spec:
  # Add fields here
  tenantAdminNamespaceName: "tenant1admin"
  tenantAdmins:
    - kind: ServiceAccount
      name: t1-admin1
      namespace: XXXXX

Once t1-admin1 is added, tenant controller will generate the following RBAC settings:

  • tenant-sample-tenant-admin-role cluster role and tenant-sample-tenant-admins-rolebinding cluster rolebindings, which allow t1-admin1 to access tenant-sample CR and tenant1admin namespace.
  • tenant-admin-role role and tenant-admins-rolebinding rolebinding in tenant1admin namespace, which allow t1-admin1 to create/update/delete tenantnamespace CR in tenant1admin namespace.

t1-admin1 can do self service namespace creation by creating a tenantnamespace CR in tenant1admin namespace:

KUBECONFIG=$PATH_TO_T1_ADMIN1_KUBECONFIG kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/multi-tenancy/master/tenant/config/samples/tenancy_v1alpha1_tenantnamespace.yaml

Tenantnamespace controller will create a t1-ns1 namespace and update tenant-sample-tenant-admin-role cluster role to allow all cluster admins to access t1-ns1 namespace.