Configure DNS to access OpenStack

Configure DNS to access OpenStack¶

The OpenStack services are exposed through the Ingress NGINX controller.

To configure DNS to access your OpenStack environment:

Obtain the external IP address of the Ingress service:

kubectl -n openstack get services ingress

Example of system response:

NAME      TYPE           CLUSTER-IP    EXTERNAL-IP    PORT(S)                                      AGE
ingress   LoadBalancer   10.96.32.97   10.172.1.101   80:34234/TCP,443:34927/TCP,10246:33658/TCP   4h56m

Select from the following options:

If you have a corporate DNS server, update your corporate DNS service and create appropriate DNS records for all OpenStack public endpoints.

To obtain the full list of public endpoints:

kubectl -n openstack get ingress -ocustom-columns=NAME:.metadata.name,HOSTS:spec.rules[*].host | awk '/cluster-fqdn/ {print $2}'

Example of system response:

barbican.it.just.works
cinder.it.just.works
cloudformation.it.just.works
designate.it.just.works
glance.it.just.works
heat.it.just.works
horizon.it.just.works
keystone.it.just.works
neutron.it.just.works
nova.it.just.works
novncproxy.it.just.works
octavia.it.just.works
placement.it.just.works

If you do not have a corporate DNS server, perform one of the following steps:

Add the appropriate records to /etc/hosts locally. For example:

172.1.101 barbican.it.just.works
172.1.101 cinder.it.just.works
172.1.101 cloudformation.it.just.works
172.1.101 designate.it.just.works
172.1.101 glance.it.just.works
172.1.101 heat.it.just.works
172.1.101 horizon.it.just.works
172.1.101 keystone.it.just.works
172.1.101 neutron.it.just.works
172.1.101 nova.it.just.works
172.1.101 novncproxy.it.just.works
172.1.101 octavia.it.just.works
172.1.101 placement.it.just.works

Deploy your DNS server on top of Kubernetes:

Deploy a standalone CoreDNS server by including the following configuration into coredns.yaml:

apiVersion: lcm.mirantis.com/v1alpha1
kind: HelmBundle
metadata:
  name: coredns
  namespace: osh-system
spec:
  repositories:
  - name: hub_stable
    url: https://kubernetes-charts.storage.googleapis.com
  releases:
  - name: coredns
    chart: hub_stable/coredns
    version: 1.8.1
    namespace: coredns
    values:
      image:
        repository: mirantis.azurecr.io/openstack/extra/coredns
        tag: "1.6.9"
      isClusterService: false
      servers:
      - zones:
        - zone: .
          scheme: dns://
          use_tcp: false
        port: 53
        plugins:
        - name: cache
          parameters: 30
        - name: errors
        # Serves a /health endpoint on :8080, required for livenessProbe
        - name: health
        # Serves a /ready endpoint on :8181, required for readinessProbe
        - name: ready
        # Required to query kubernetes API for data
        - name: kubernetes
          parameters: cluster.local
        - name: loadbalance
          parameters: round_robin
        # Serves a /metrics endpoint on :9153, required for serviceMonitor
        - name: prometheus
          parameters: 0.0.0.0:9153
        - name: forward
          parameters: . /etc/resolv.conf
        - name: file
          parameters: /etc/coredns/it.just.works.db it.just.works
      serviceType: LoadBalancer
      zoneFiles:
      - filename: it.just.works.db
        domain: it.just.works
        contents: |
          it.just.works.            IN      SOA     sns.dns.icann.org. noc.dns.icann.org. 2015082541 7200 3600 1209600 3600
          it.just.works.            IN      NS      b.iana-servers.net.
          it.just.works.            IN      NS      a.iana-servers.net.
          it.just.works.            IN      A       1.2.3.4
          *.it.just.works.           IN      A      1.2.3.4

Update the public IP address of the Ingress service:

sed -i 's/1.2.3.4/10.172.1.101/' release/ci/30-coredns.yaml
kubectl apply -f release/ci/30-coredns.yaml

Verify that the DNS resolution works properly:

Assign an external IP to the service:

kubectl -n coredns patch service coredns-coredns --type='json' -p='[{"op": "replace", "path": "/spec/ports", "value": [{"name": "udp-53", "port": 53, "protocol": "UDP", "targetPort": 53}]}]'
kubectl -n coredns patch service coredns-coredns --type='json' -p='[{"op": "replace", "path": "/spec/type", "value":"LoadBalancer"}]'

Obtain the external IP address of CoreDNS:

kubectl -n coredns get service coredns-coredns

Example of system response:

NAME              TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)         AGE
coredns-coredns   ClusterIP   10.96.178.21   10.172.1.102      53/UDP,53/TCP   25h

Point your machine to use the correct DNS. It is 10.172.1.102 in the example system response above.
If you plan to launch Tempest tests or use the OpenStack client from a keystone-client-XXX pod, verify that the Kubernetes built-in DNS service is configured to resolve your public FQDN records by adding your public domain to the stubdomain list. For example, to add the it.just.works domain:
```
kubectl -n kube-system get configmap kube-dns -o jsonpath='{.data.stubDomains}'
{"mirantis.net": ["172.18.208.44"],
 "it.just.works": ["10.96.178.21"]
}
```

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