drubin / rbac-manager

A Kubernetes operator that simplifies the management of Role Bindings and Service Accounts.

RBAC Manager

RBAC Manager was designed to simplify authorization in Kubernetes. This is an operator that supports declarative configuration for RBAC with new custom resources. Instead of managing role bindings or service accounts directly, you can specify a desired state and RBAC Manager will make the necessary changes to achieve that state.

This project has three main goals:

1. Provide a declarative approach to RBAC that is more approachable and scalable.
2. Reduce the amount of configuration required for great auth.
3. Enable automation of RBAC configuration updates with CI/CD.

An Example

To fully understand how RBAC Manager works, it's helpful to walk through a simple example. In this example we'll have a single user, Joe, that needs edit access to the web namespace and view access to api namespace.

With RBAC, that requires creating 2 role bindings, the first grants edit access to the web namespace.

kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: joe-web
  namespace: web
subjects:
- kind: User
  name: [email protected]
roleRef:
  kind: ClusterRole
  name: edit
  apiGroup: rbac.authorization.k8s.io

The second grants view access to the api namespace.

kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: joe-api
  namespace: api
subjects:
- kind: User
  name: [email protected]
roleRef:
  kind: ClusterRole
  name: api
  apiGroup: rbac.authorization.k8s.io

It's easy to see just how repetitive this becomes. With RBAC Manager, we can use a custom resource to achieve the same result.

apiVersion: rbacmanager.reactiveops.io/v1beta1
kind: RBACDefinition
metadata:
  name: joe-access
rbacBindings:
  - name: joe
    subjects:
      - kind: User
        name: [email protected]
    roleBindings:
      - namespace: api
        clusterRole: view
      - namespace: web
        clusterRole: edit

The Benefits

With an RBAC Definition custom resource, we can cut the amount of configuration in half (or often significantly more). RBAC Manager is deployed as an operator and listens for new and updated RBAC Definitions, making the necessary changes to achieve the desired state.

This approach is incredibly helpful for 2 specific cases:

1. Updating a Role Binding

Unfortunately there's no way to change the role an existing Kubernetes Role Binding refers to. That means that changing a role granted to a user involves deleting and recreating a Kubernetes Role Binding. With RBAC Manager, that process happens automatically when an RBAC Definition is updated.

2. Detecting Role Binding Removal

When it comes to potential CI automation of changes to RBAC configuration, tracking the removal of a role binding can get quite tricky. If you were using a traditional workflow where desired Kubernetes objects are represent in a repo as yaml files, the creates and updates are reasonably straightforward, but revoking access on the basis of a Role Binding being removed is quite tricky.

With RBAC Manager, each RBAC Definition "owns" any resources it creates, and will always compare the desired state in the current RBAC Definition with the list of resources currently owned by it. If a Role Binding is no longer included in a RBAC Definition, RBAC Manager will automatically remove it.

Getting Started

RBAC Manager is simple to install with either the Helm chart or Kubernetes deployment YAML included in this repo:

helm repo add reactiveops-stable https://charts.reactiveops.com/stable
helm install reactiveops-stable/rbac-manager --name rbac-manager --namespace rbac-manager

kubectl apply -f deploy/

Once RBAC Manager is installed in your cluster, you'll be able to deploy RBAC Definitions to your cluster. There are examples of these custom resources above as well as in the examples directory of this repository.

Dynamic Namespaces and Labels

RBAC Definitions can now include namespaceSelectors in place of namespace attributes when specifying Role Binding configuration. This can be incredibly helpful when working with dynamically provisioned namespaces.

apiVersion: rbacmanager.reactiveops.io/v1beta1
kind: RBACDefinition
metadata:
  name: dev-access
rbacBindings:
  - name: dev-team
    subjects:
      - kind: Group
        name: dev-team
    roleBindings:
      - clusterRole: edit
        namespaceSelector:
          matchLabels:
            team: dev

In the example above, Role Bindings would automatically get created for each Namespace with a team=dev label.

Further Reading

RBAC Definitions

RBAC Definitions can manage Cluster Role Bindings, Role Bindings, and Service Accounts. To better understand how these work, read our RBAC Definition documentation.

Cloud Specific Authentication Tips

To properly configure authorization with RBAC in Kubernetes, you first need to have good authentication. We've provided some helpful documentation for working with authentication on AWS, Google Cloud, and Azure.

Better Visibility With RBAC Lookup

We have a related open source tool that allows you to easily find roles and cluster roles attached to any user, service account, or group name in your Kubernetes cluster. If that sounds interesting, take a look at rbac-lookup on GitHub.

License

Apache License 2.0