How-To: Scope components to one or more applications

Limit component access to particular Dapr instances

Dapr components are namespaced (separate from the Kubernetes namespace concept), meaning a Dapr runtime instance can only access components that have been deployed to the same namespace.

Namespaces

Namespaces can be used to limit component access to particular Dapr instances.

Example of component namespacing in Kubernetes

Let’s consider the following component in Kubernetes:

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: statestore
  namespace: production
spec:
  type: state.redis
  metadata:
  - name: redisHost
    value: redis-master:6379

In this example, the Redis component is only accessible to Dapr instances running inside the production namespace.

Example of component namsespacing in self-hosted mode

In self hosted mode, a developer can specify the namespace to a Dapr instance by setting the NAMESPACE environment variable. If the NAMESPACE environment variable is set, Dapr will not load any component that does not specify the same namespace in its metadata.

Considering the example above, to tell Dapr which namespace it is deployed to, set the environment variable:

MacOS/Linux:

export NAMESPACE=production

# run Dapr as usual

Windows:

setx NAMESPACE "production"

# run Dapr as usual

When Dapr runs, it matches it’s own configured namespace with the namespace of the components that it loads and initializes only the the one matching its namespaces. All other components in a different namespace are not loaded.

Application access to components with scopes

Developers and operators might want to limit access for one database to a certain application, or a specific set of applications. To achieve this, Dapr allows you to specify scopes on the component YAML. Application scopes added to a component limit only the applications with specific IDs to be able to use the component.

The following example shows how to give access to two Dapr enabled apps, with the app IDs of app1 and app2 to the Redis component named statestore which itself is in the production namespace

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: statestore
  namespace: production
spec:
  type: state.redis
  metadata:
  - name: redisHost
    value: redis-master:6379
scopes:
- app1
- app2

Example

Last modified November 20, 2020: Revert commands for 0.11 (#947) (904c3d3)