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Consul
Consul on Kubernetes

Ingress with Consul on Kubernetes

  • 10min

  • Consul

In this tutorial, you will enable external access into your service mesh by deploying a Consul API Gateway. Consul API Gateway provides a consistent method to handle inbound requests and route them to the appropriate service within your service mesh.

Select your learning path by clicking one of the following tabs.

To set up ingress into your service mesh, you will:

  • Enable Consul ingress features
  • Deploy Consul API Gateway
  • Deploy RBAC and Reference Grant resources
  • View Consul services with the CLI, UI, and/or API
  • Explore ingress into the HashiCups UI

Prerequisites

The tutorial assumes that you have completed the previous tutorials in this getting started collection.

For this tutorial, you will need:

Enable Consul ingress features

You will now enable additional Consul features in your Kubernetes cluster using the official Consul Helm chart or the consul-k8s CLI.

Consul API Gateway implements and is configured through the Kubernetes Gateway API Specification. This specification defines a set of custom resource definitions (CRDs) that can create logical gateways which route traffic based on a client request's path or protocol.

First, create the custom resource definitions (CRD) for the API Gateway Controller. 

$ kubectl apply --kustomize "github.com/hashicorp/consul-api-gateway/config/crd?ref=v0.5.1"
customresourcedefinition.apiextensions.k8s.io/gatewayclassconfigs.api-gateway.consul.hashicorp.com created
customresourcedefinition.apiextensions.k8s.io/gatewayclasses.gateway.networking.k8s.io created
customresourcedefinition.apiextensions.k8s.io/gateways.gateway.networking.k8s.io created
customresourcedefinition.apiextensions.k8s.io/httproutes.gateway.networking.k8s.io created
customresourcedefinition.apiextensions.k8s.io/meshservices.api-gateway.consul.hashicorp.com created
customresourcedefinition.apiextensions.k8s.io/referencepolicies.gateway.networking.k8s.io created
customresourcedefinition.apiextensions.k8s.io/tcproutes.gateway.networking.k8s.io created
customresourcedefinition.apiextensions.k8s.io/tlsroutes.gateway.networking.k8s.io created
customresourcedefinition.apiextensions.k8s.io/udproutes.gateway.networking.k8s.io created

Review the additional configuration details.

helm/values-v2.yaml
# Contains values that affect multiple components of the chart.
global:
 ## ...

# Configures and installs the Consul API Gateway.
apiGateway:
 enabled: true
 # Image to use for the api-gateway-controller pods and gateway instances
 image: "hashicorp/consul-api-gateway:0.5.1"
 # Configuration settings for the GatewayClass
 managedGatewayClass:
   # Defines the type of service created for gateways (e.g. LoadBalancer, ClusterIP, NodePort)
   # LoadBalancer is primarily used for cloud deployments.
   serviceType: LoadBalancer

Since these Consul resources are managed with Terraform, the respective module's Helm configuration file controls the Helm chart deployment for this environment.

Update your Consul deployment's Helm chart values.

cp helm/values-v2.yaml modules/eks-client/template/consul.tpl

Then, deploy the resources. Confirm the run by entering yes.

$ terraform apply

## ...
Do you want to perform these actions?
 Terraform will perform the actions described above.
 Only 'yes' will be accepted to approve.

 Enter a value: yes

## ...

Apply complete! Resources: 1 added, 1 changed, 1 destroyed.

Deploy Consul API Gateway

Review Consul API Gateway configuration

Now that you have enabled ingress features in your Consul service mesh, you can deploy the Consul API Gateway and associated HTTP Routes to your Kubernetes cluster. The Consul API Gateway uses HTTP Routes to route traffic to your applications.

Review the api-gw/consul-api-gateway.yaml configuration file. This file contains the configuration for the API Gateway pod, the listener, and TLS attributes.

api-gw/consul-api-gateway.yaml
apiVersion: gateway.networking.k8s.io/v1alpha2
# The Gateway is the main infrastructure resource that links API gateway components.
kind: Gateway
metadata:
  name: api-gateway
  namespace: consul
spec:
  gatewayClassName: consul-api-gateway
  # Configures the listener that is bound to the gateway's address.
  listeners:
    # Defines the listener protocol (HTTP, HTTPS, or TCP)
  - protocol: HTTP
    port: 8080
    name: http
    allowedRoutes:
      namespaces:
        from: Same

Review the api-gw/routes.yaml configuration file. This file contains the configuration for HTTP routing including the network traffic rules and the backend service that will receive the ingress traffic.

api-gw/routes.yaml
apiVersion: gateway.networking.k8s.io/v1alpha2
# HTTPRoute routes HTTP requests to backend services.
kind: HTTPRoute
metadata:
  name: http-route-1
  namespace: consul
spec:
  # Defines the gateway listener.
  parentRefs:
  - name: api-gateway
  # Rules define behaviors for network traffic that goes through the route.
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /
    # Defines the backend service.
    backendRefs:
    - kind: Service
      name: nginx
      namespace: default
      port: 80

Deploy Consul API Gateway

Next, deploy the API Gateway, wait for the API Gateway to completely deploy, and deploy the routes. 

$ kubectl apply --filename api-gw/consul-api-gateway.yaml --namespace consul && \
kubectl wait --for=condition=ready gateway/api-gateway --namespace consul --timeout=90s && \
kubectl apply --filename api-gw/routes.yaml --namespace consul

Expected output:

gateway.gateway.networking.k8s.io/api-gateway created
gateway.gateway.networking.k8s.io/api-gateway condition met
httproute.gateway.networking.k8s.io/http-route-1 created

Verify you have created all the pods in your consul namespace. You should find an output similar to the following.

$ kubectl get pods --namespace consul | grep "api-gateway"
NAME                                             READY   STATUS    RESTARTS   AGE
api-gateway-6ddbd69979-bm5kq                     1/1     Running   0          64s
consul-api-gateway-controller-66dddfb4c8-jj8w2   1/1     Running   1          7m9s

The diagram below shows the services running in your Kubernetes cluster. This includes Consul API Gateway, service mesh layer, and HashiCups microservice application pods.

Kubernetes and Application Architecture for this tutorial

Consul API Gateway enables ingress, load-balancing, and other advanced traffic behavior for your service mesh applications. In this tutorial, Consul API Gateway allows external traffic into the HashiCups service.

Deploy RBAC and Reference Grant resources

Now that Consul API Gateway is operational in your cluster, you will deploy role-based access control (RBAC) and Reference Grant resources. RBAC enables the Consul API gateway to interact with Consul datacenter resources and reference grants enable the Consul API Gateway to route traffic between different namespaces.

Deploy the RBAC and Reference Grant resources.

$ kubectl apply --filename hashicups/v2/
clusterrolebinding.rbac.authorization.k8s.io/consul-api-gateway-tokenreview-binding created
clusterrole.rbac.authorization.k8s.io/consul-api-gateway-auth created
clusterrolebinding.rbac.authorization.k8s.io/consul-api-gateway-auth-binding created
clusterrolebinding.rbac.authorization.k8s.io/consul-auth-binding created
referencegrant.gateway.networking.k8s.io/consul-reference-grant created

View Consul services

In this section, you will view your Consul services with the CLI, UI, and/or API to explore the details of your service mesh ingress.

In your terminal, run the CLI command consul catalog services to return the api-gateway service registered in Consul.

$ consul catalog services | grep api-gateway
api-gateway

Return the list of Consul intentions. Consul automatically creates intentions between the Consul API Gateway and any destination services defined in your route configuration files. In this case, it created an intention to allow traffic from api-gateway to nginx.

$ consul intention list
ID  Source       Action  Destination     Precedence
    api-gateway  allow   nginx           9
    nginx        allow   frontend        9
    nginx        allow   public-api      9
    product-api  allow   product-api-db  9
    public-api   allow   payments        9
    public-api   allow   product-api     9

Explore ingress into the demo application

Set your Consul API Gateway address to the CONSUL_APIGW_ADDR environment variable. 

$ export CONSUL_APIGW_ADDR=http://$(kubectl get svc/api-gateway --namespace consul -o json | jq -r '.status.loadBalancer.ingress[0].hostname'):8080

Output the Consul API Gateway value to your terminal and paste it in your browser to access the HashiCups UI through the API Gateway.

$ echo $CONSUL_APIGW_ADDR
http://a46cc0cc9dc6841a4b1a0fa1771973ca-1032165333.us-west-2.elb.amazonaws.com:8080

HashiCups UI

For more information on accessing service mesh services via the Consul API Gateway, visit the Consul API Gateway documentation page.

Next Steps

In this tutorial, you enabled Consul ingress features and deployed Consul API Gateway into your Kubernetes cluster. After deploying Consul API Gateway, you accessed the demo application HashiCups through the Consul API Gateway endpoint and explored how ingress into a service mesh application works.

In the next tutorial, you will deploy an observability suite to explore metrics, logs, and distributed traces within your Consul service mesh.

For more information about the topics covered in this tutorial, refer to the following resources:

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