Using External Services Discovery In ApisixUpstream

In this tutorial, we will introduce how to configure external services discovery in the ApisixUpstream resources.

APISIX already supports various service discovery components, such as DNS, consul, nacos, etc. Please see Integration service discovery registry for details.

Prerequisites

• An available Kubernetes cluster
• An available APISIX and APISIX Ingress Controller installation

We assume that your APISIX is installed in the apisix namespace.

Introduction

Integration of APISIX Ingress with service discovery components is configured through the ApisixUpstream resource. In this case, we don't configure the backends field in the ApisixRoute resource. Instead, we will use the upstreams field to refer to an ApisixUpstream resources with the discovery field configured.

For example:

# httpbin-route.yaml
apiVersion: apisix.apache.org/v2
kind: ApisixRoute
metadata:
  name: httpbin-route
spec:
  http:
  - name: rule1
    match:
      hosts:
      - local.httpbin.org
      paths:
      - /*
    # backends:  # We won't use the `backends` field
    #    - serviceName: httpbin
    #      servicePort: 80
    upstreams:
    - name: httpbin-upstream

This configuration tells the ingress controller not to resolve upstream hosts through the K8s services, but to use the configuration defined in the referenced ApisixUpstream. The referenced ApisixUpstream MUST have discovery field configured. For example:

# httpbin-upstream.yaml
apiVersion: apisix.apache.org/v2
kind: ApisixUpstream
metadata:
  name: httpbin-upstream
spec:
  discovery:
    type: dns
    serviceName: httpbin.default.svc.cluster.local

In this yaml example, we configured httpbin.default.svc.cluster.local as the backend. The type of service discovery needs to be pre-configured in APISIX. For example:

discovery:
  dns:
    servers:
      - "10.96.0.10:53" # default kube-dns cluster IP.

After applying the above configuration, we can try to access httpbin.default.svc.cluster.local directly through APISIX.