k8s_multi_cluster_dns_discovery

2-cluster-example.yaml

# This example exposes service/foo from cluster1 and cluster2 so it's reachable
# by foo.example.com. DNS is used to load-balance traffic to foo.example.com
# across cluster1 and cluster2.
#
# Note that a DNSRecord is not needed to create the multi-cluster FQDN for the
# foo services in both clusters. A controller watches xRoutes and creates a DNS
# record from the xRoute's hostname.
---
# A new resource for managing multi-cluster DNS records.
apiVersion: dns.x-k8s.io/v1alpha1
kind: DNSRecord
metadata:
  name: foo
spec:
  # dnsName could be an xref to a separate resource for DNS domain, zone, etc. management.
  # Creates a CNAME record for foo.example.com -> foo.default.cluster1.svc.cluster.local & foo.default.cluster2.svc.cluster.local
  dnsName: foo.example.com
  recordTTL: 300
  targets:
  - resource: Gateway
    name: cluster1-gateway
  - resource: Gateway
    name: cluster2-gateway
    # A secret containing cluster-2 kubeconfig. Local cluster assumed if creds is nil.
    creds: cluster2-kubeconfig
status:
  addresses:
  - name: cluster1-gateway
    listener: http-listener
    address: 1.1.1.1 # Cluster 1 gateway listener ip.
  - name: cluster2-gateway
    listener: http-listener
    address: 2.2.2.2 # Cluster 2 gateway listener ip.
---
# Cluster-1 Gateway config.
kind: Gateway
apiVersion: networking.x-k8s.io/v1alpha1
metadata:
  name: cluster1-gateway
spec:
  class: my-lb # Note the GatewayClass is not ommitted from this example.
  listeners:
  - name: http-listener
    protocol: HTTP
  routes:
    routeSelector:
      matchLabels:
        "app": "foo"
status:
  addresses:
  - name: http-listener
    address: 1.1.1.1
---
# Cluster-1 HTTPRoute that forwards http requests for foo1.example.com to service "foo-service"
kind: HTTPRoute
apiVersion: networking.x-k8s.io/v1alpha1
metadata:
  name: http-example
  labels:
    app: foo
spec:
  hosts:
    - hostname: foo1.example.com
      rules:
          action:
            forwardTo:
              targetRef:
                name: foo1-service
---
# Cluster-2 Gateway config.
kind: Gateway
apiVersion: networking.x-k8s.io/v1alpha1
metadata:
  name: cluster2-gateway
spec:
  class: my-lb # Note the GatewayClass is not ommitted from this example.
  listeners:
  - name: http-listener
    protocol: HTTP
  routes:
    routeSelector:
      matchLabels:
        "app": "foo"
status:
  addresses:
  - name: http-listener
    address: 2.2.2.2
---
# Cluster-2 HTTPRoute that forwards http requests for foo2.example.com to service "foo-service"
kind: HTTPRoute
apiVersion: networking.x-k8s.io/v1alpha1
metadata:
  name: http-example
  labels:
    app: foo
spec:
  hosts:
    - hostname: foo2.example.com
      rules:
          action:
            forwardTo:
              targetRef:
                name: foo-service