HashiCorp Consul

Detailed information on the HashiCorp Consul name resolution component

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

Field Required Type Details Examples
Client N *api.Config Configures client connection to the Consul agent. If blank it will use the sdk defaults, which in this case is just an address of 127.0.0.1:8500 10.0.4.4:8500
QueryOptions N *api.QueryOptions Configures query used for resolving healthy services, if blank it will default to UseCache:true UseCache: false, Datacenter: "myDC"
Checks N []*api.AgentServiceCheck Configures health checks if/when registering. If blank it will default to a single health check on the Dapr sidecar health endpoint See sample configs
Tags N []string Configures any tags to include if/when registering services - "dapr"
Meta N map[string]string Configures any additional metadata to include if/when registering services DAPR_METRICS_PORT: "${DAPR_METRICS_PORT}"
DaprPortMetaKey N string The key used for getting the Dapr sidecar port from Consul service metadata during service resolution, it will also be used to set the Dapr sidecar port in metadata during registration. If blank it will default to DAPR_PORT "DAPR_TO_DAPR_PORT"
SelfRegister N bool Controls if Dapr will register the service to Consul. The name resolution interface does not cater for an “on shutdown” pattern so please consider this if using Dapr to register services to Consul as it will not deregister services. If blank it will default to false true
AdvancedRegistration N *api.AgentServiceRegistration Gives full control of service registration through configuration. If configured the component will ignore any configuration of Checks, Tags, Meta and SelfRegister. See sample configs

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


HashiCorp offer in depth guides on how to setup Consul for different hosting models. Check out the self-hosted guide here


HashiCorp offer in depth guides on how to setup Consul for different hosting models. Check out the Kubernetes guide here


Last modified May 31, 2024: Merge 61e65296a85dd35c3b7040b281b7c17caffcc144 into 27b6a61b0e1b0a30ea4e4f31bea712dfec3813b3 (525f2ab)