Setting up ExternalDNS for Services on OVH¶
This tutorial describes how to setup ExternalDNS for use within a
Kubernetes cluster using OVH DNS.
Make sure to use >=0.6 version of ExternalDNS for this tutorial.
Creating a zone with OVH DNS¶
If you are new to OVH, we recommend you first read the following
instructions for creating a zone.
Creating a zone using the OVH manager
Creating a zone using the OVH API
Creating OVH Credentials¶
You first need to create an OVH application.
Using the OVH documentation you will have your Application key and Application secret
And you will need to generate your consumer key, here the permissions needed :
- GET on /domain/zone
- GET on /domain/zone/*/record
- GET on /domain/zone/*/record/*
- POST on /domain/zone/*/record
- DELETE on /domain/zone/*/record/*
- POST on /domain/zone/*/refresh
You can use the following curl request to generate & validated your Consumer key
curl -XPOST -H "X-Ovh-Application: <ApplicationKey>" -H "Content-type: application/json" https://eu.api.ovh.com/1.0/auth/credential -d '{
"accessRules": [
{
"method": "GET",
"path": "/domain/zone"
},
{
"method": "GET",
"path": "/domain/zone/*/record"
},
{
"method": "GET",
"path": "/domain/zone/*/record/*"
},
{
"method": "POST",
"path": "/domain/zone/*/record"
},
{
"method": "DELETE",
"path": "/domain/zone/*/record/*"
},
{
"method": "POST",
"path": "/domain/zone/*/refresh"
}
],
"redirection":"https://github.com/kubernetes-sigs/external-dns/blob/HEAD/docs/tutorials/ovh.md#creating-ovh-credentials"
}'
Deploy ExternalDNS¶
Connect your kubectl client to the cluster with which you want to test ExternalDNS, and then apply one of the following manifest files for deployment:
Manifest (for clusters without RBAC enabled)¶
apiVersion: apps/v1
kind: Deployment
metadata:
name: external-dns
spec:
strategy:
type: Recreate
selector:
matchLabels:
app: external-dns
template:
metadata:
labels:
app: external-dns
spec:
containers:
- name: external-dns
image: registry.k8s.io/external-dns/external-dns:v0.13.5
args:
- --source=service # ingress is also possible
- --domain-filter=example.com # (optional) limit to only example.com domains; change to match the zone created above.
- --provider=ovh
env:
- name: OVH_APPLICATION_KEY
value: "YOUR_OVH_APPLICATION_KEY"
- name: OVH_APPLICATION_SECRET
value: "YOUR_OVH_APPLICATION_SECRET"
- name: OVH_CONSUMER_KEY
value: "YOUR_OVH_CONSUMER_KEY_AFTER_VALIDATED_LINK"
Manifest (for clusters with RBAC enabled)¶
apiVersion: v1
kind: ServiceAccount
metadata:
name: external-dns
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: external-dns
rules:
- apiGroups: [""]
resources: ["services"]
verbs: ["get","watch","list"]
- apiGroups: [""]
resources: ["pods"]
verbs: ["get","watch","list"]
- apiGroups: ["extensions","networking.k8s.io"]
resources: ["ingresses"]
verbs: ["get","watch","list"]
- apiGroups: [""]
resources: ["nodes"]
verbs: ["list"]
- apiGroups: [""]
resources: ["endpoints"]
verbs: ["get","watch","list"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: external-dns-viewer
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: external-dns
subjects:
- kind: ServiceAccount
name: external-dns
namespace: default
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: external-dns
spec:
strategy:
type: Recreate
selector:
matchLabels:
app: external-dns
template:
metadata:
labels:
app: external-dns
spec:
serviceAccountName: external-dns
containers:
- name: external-dns
image: registry.k8s.io/external-dns/external-dns:v0.13.5
args:
- --source=service # ingress is also possible
- --domain-filter=example.com # (optional) limit to only example.com domains; change to match the zone created above.
- --provider=ovh
env:
- name: OVH_APPLICATION_KEY
value: "YOUR_OVH_APPLICATION_KEY"
- name: OVH_APPLICATION_SECRET
value: "YOUR_OVH_APPLICATION_SECRET"
- name: OVH_CONSUMER_KEY
value: "YOUR_OVH_CONSUMER_KEY_AFTER_VALIDATED_LINK"
Deploying an Nginx Service¶
Create a service file called ‘nginx.yaml’ with the following contents:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- image: nginx
name: nginx
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx
annotations:
external-dns.alpha.kubernetes.io/hostname: example.com
external-dns.alpha.kubernetes.io/ttl: "120" #optional
spec:
selector:
app: nginx
type: LoadBalancer
ports:
- protocol: TCP
port: 80
targetPort: 80
A note about annotations
Verify that the annotation on the service uses the same hostname as the OVH DNS zone created above. The annotation may also be a subdomain of the DNS zone (e.g. ‘www.example.com’).
The TTL annotation can be used to configure the TTL on DNS records managed by ExternalDNS and is optional. If this annotation is not set, the TTL on records managed by ExternalDNS will default to 10.
ExternalDNS uses the hostname annotation to determine which services should be registered with DNS. Removing the hostname annotation will cause ExternalDNS to remove the corresponding DNS records.
Create the deployment and service¶
Depending on where you run your service, it may take some time for your cloud provider to create an external IP for the service. Once an external IP is assigned, ExternalDNS detects the new service IP address and synchronizes the OVH DNS records.
Verifying OVH DNS records¶
Use the OVH manager or API to verify that the A record for your domain shows the external IP address of the services.
Cleanup¶
Once you successfully configure and verify record management via ExternalDNS, you can delete the tutorial’s example: