Name resolution provider component specs

• 1: HashiCorp Consul
• 2: Kubernetes DNS
• 3: mDNS
• 4: SQLite

<tr>
    <td><a href="/reference/components-reference/supported-name-resolution/setup-nr-consul/">HashiCorp Consul</a>
    </td>
    <td>Alpha</td>
    <td>v1</td>
    <td>1.2</td>
</tr>

<tr>
    <td><a href="/reference/components-reference/supported-name-resolution/nr-sqlite/">SQLite</a>
    </td>
    <td>Alpha</td>
    <td>v1</td>
    <td>1.13</td>
</tr>

<tr>
    <td><a href="/reference/components-reference/supported-name-resolution/nr-kubernetes/">Kubernetes</a>
    </td>
    <td>Stable</td>
    <td>v1</td>
    <td>1.0</td>
</tr>

<tr>
    <td><a href="/reference/components-reference/supported-name-resolution/nr-mdns/">mDNS</a>
    </td>
    <td>Stable</td>
    <td>v1</td>
    <td>1.0</td>
</tr>

1 - HashiCorp Consul

Configuration format

Hashicorp Consul is setup within the Dapr Configuration.

Within the config, add a nameResolution spec and set the component field to "consul".

If you are using the Dapr sidecar to register your service to Consul then you will need the following configuration:

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "consul"
    configuration:
      selfRegister: true

If Consul service registration is managed externally from Dapr you need to ensure that the Dapr-to-Dapr internal gRPC port is added to the service metadata under DAPR_PORT (this key is configurable) and that the Consul service Id matches the Dapr app Id. You can then omit selfRegister from the config above.

Behaviour

On init the Consul component either validates the connection to the configured (or default) agent or registers the service if configured to do so. The name resolution interface does not cater for an “on shutdown” pattern so consider this when using Dapr to register services to Consul as it does not deregister services.

The component resolves target apps by filtering healthy services and looks for a DAPR_PORT in the metadata (key is configurable) in order to retrieve the Dapr sidecar port. Consul service.meta is used over service.port so as to not interfere with existing Consul estates.

Spec configuration fields

The configuration spec is fixed to v1.3.0 of the Consul API

Sample configurations

Basic

The minimum configuration needed is the following:

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "consul"

Registration with additional customizations

Enabling SelfRegister it is then possible to customize the checks, tags and meta

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "consul"
    configuration:
      client:
        address: "127.0.0.1:8500"
      selfRegister: true
      checks:
        - name: "Dapr Health Status"
          checkID: "daprHealth:${APP_ID}"
          interval: "15s"
          http: "http://${HOST_ADDRESS}:${DAPR_HTTP_PORT}/v1.0/healthz"
        - name: "Service Health Status"
          checkID: "serviceHealth:${APP_ID}"
          interval: "15s"
          http: "http://${HOST_ADDRESS}:${APP_PORT}/health"
      tags:
        - "dapr"
        - "v1"
        - "${OTHER_ENV_VARIABLE}"
      meta:
        DAPR_METRICS_PORT: "${DAPR_METRICS_PORT}"
        DAPR_PROFILE_PORT: "${DAPR_PROFILE_PORT}"
      daprPortMetaKey: "DAPR_PORT"
      queryOptions:
        useCache: true
        filter: "Checks.ServiceTags contains dapr"

Advanced registration

Configuring the advanced registration gives you full control over setting all the Consul properties possible when registering.

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "consul"
    configuration:
      client:
          address: "127.0.0.1:8500"
      selfRegister: false
      queryOptions:
        useCache: true
      daprPortMetaKey: "DAPR_PORT"
      advancedRegistration:
        name: "${APP_ID}"
        port: ${APP_PORT}
        address: "${HOST_ADDRESS}"
        check:
          name: "Dapr Health Status"
          checkID: "daprHealth:${APP_ID}"
          interval: "15s"
          http: "http://${HOST_ADDRESS}:${DAPR_HTTP_PORT}/v1.0/healthz"
        meta:
          DAPR_METRICS_PORT: "${DAPR_METRICS_PORT}"
          DAPR_PROFILE_PORT: "${DAPR_PROFILE_PORT}"
        tags:
          - "dapr"

Setup HashiCorp Consul

• Self-Hosted
• Kubernetes

Related links

• Service invocation building block

2 - Kubernetes DNS

Configuration format

Generally, Kubernetes DNS name resolution is configured automatically in Kubernetes mode by Dapr. There is no configuration needed to use Kubernetes DNS as your name resolution provider unless some overrides are necessary for the Kubernetes name resolution component.

In the scenario that an override is required, within a Dapr Configuration CRD, add a nameResolution spec and set the component field to "kubernetes". The other configuration fields can be set as needed in a configuration map, as seen below.

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "kubernetes"
    configuration:
      clusterDomain: "cluster.local"  # Mutually exclusive with the template field
      template: "{{.ID}}-{{.Data.region}}.internal:{{.Port}}" # Mutually exclusive with the clusterDomain field

Behaviour

The component resolves target apps by using the Kubernetes cluster’s DNS provider. You can learn more in the Kubernetes docs.

Spec configuration fields

The configuration spec is fixed to v1.3.0 of the Consul API

Related links

• Service invocation building block
• Kubernetes DNS docs

3 - mDNS

Configuration format

Multicast DNS (mDNS) is configured automatically in self-hosted mode by Dapr. There is no configuration needed to use mDNS as your name resolution provider.

Behaviour

The component resolves target apps by using the host system’s mDNS service. You can learn more about mDNS here.

Troubleshooting

In some cloud provider virtual networks, such as Microsoft Azure, mDNS is not available. Use an alternate provider such as HashiCorp Consul instead.

On some enterprise-managed systems, mDNS may be disabled on macOS if a network filter/proxy is configured. Check with your IT department if mDNS is disabled and you are unable to use service invocation locally.

Spec configuration fields

Not applicable, as mDNS is configured by Dapr when running in self-hosted mode.

Related links

• Service invocation building block
• mDNS reference

4 - SQLite

As an alternative to mDNS, the SQLite name resolution component can be used for running Dapr on single-node environments and for local development scenarios. Dapr sidecars that are part of the cluster store their information in a SQLite database on the local machine.

Configuration format

Name resolution is configured via the Dapr Configuration.

Within the Configuration YAML, set the spec.nameResolution.component property to "sqlite", then pass configuration options in the spec.nameResolution.configuration dictionary.

This is the basic example of a Configuration resource:

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "sqlite"
    version: "v1"
    configuration:
      connectionString: "/home/user/.dapr/nr.db"

Spec configuration fields

When using the SQLite name resolver component, the spec.nameResolution.configuration dictionary contains these options:

Related links

• Service invocation building block