# Setting up ExternalDNS for CoreDNS with minikube
This tutorial describes how to setup ExternalDNS for usage within a [minikube](https://github.com/kubernetes/minikube) cluster that makes use of [CoreDNS](https://github.com/coredns/coredns) and [nginx ingress controller](https://github.com/kubernetes/ingress-nginx).
You need to:
* install CoreDNS with [etcd](https://github.com/etcd-io/etcd) enabled
* install external-dns with coredns as a provider
* enable ingress controller for the minikube cluster
## Creating a cluster
```
minikube start
```
## Installing CoreDNS with etcd enabled
Helm chart is used to install etcd and CoreDNS.
### Initializing helm chart
```
helm init
```
### Installing etcd
[etcd operator](https://github.com/coreos/etcd-operator) is used to manage etcd clusters.
```
helm install stable/etcd-operator --name my-etcd-op
```
etcd cluster is installed with example yaml from etcd operator website.
```
kubectl apply -f https://raw.githubusercontent.com/coreos/etcd-operator/HEAD/example/example-etcd-cluster.yaml
```
### Installing CoreDNS
In order to make CoreDNS work with etcd backend, values.yaml of the chart should be changed with corresponding configurations.
```
wget https://raw.githubusercontent.com/helm/charts/HEAD/stable/coredns/values.yaml
```
You need to edit/patch the file with below diff
```
diff --git a/values.yaml b/values.yaml
index 964e72b..e2fa934 100644
--- a/values.yaml
+++ b/values.yaml
@@ -27,12 +27,12 @@ service:
rbac:
# If true, create & use RBAC resources
- create: false
+ create: true
# Ignored if rbac.create is true
serviceAccountName: default
# isClusterService specifies whether chart should be deployed as cluster-service or normal k8s app.
-isClusterService: true
+isClusterService: false
servers:
- zones:
@@ -51,6 +51,12 @@ servers:
parameters: 0.0.0.0:9153
- name: proxy
parameters: . /etc/resolv.conf
+ - name: etcd
+ parameters: example.org
+ configBlock: |-
+ stubzones
+ path /skydns
+ endpoint http://10.105.68.165:2379
# Complete example with all the options:
# - zones: # the `zones` block can be left out entirely, defaults to "."
```
**Note**:
* IP address of etcd's endpoint should be get from etcd client service. It should be "example-etcd-cluster-client" in this example. This IP address is used through this document for etcd endpoint configuration.
```
$ kubectl get svc example-etcd-cluster-client
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
example-etcd-cluster-client ClusterIP 10.105.68.165 <none> 2379/TCP 16m
```
* Parameters should configure your own domain. "example.org" is used in this example.
After configuration done in values.yaml, you can install coredns chart.
```
helm install --name my-coredns --values values.yaml stable/coredns
```
## Installing ExternalDNS
### Install external ExternalDNS
ETCD_URLS is configured to etcd client service address.
#### Manifest (for clusters without RBAC enabled)
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: external-dns
namespace: kube-system
spec:
strategy:
type: Recreate
selector:
matchLabels:
app: external-dns
template:
metadata:
labels:
app: external-dns
spec:
containers:
- name: external-dns
image: k8s.gcr.io/external-dns/external-dns:v0.7.3
args:
- --source=ingress
- --provider=coredns
- --log-level=debug # debug only
env:
- name: ETCD_URLS
value: http://10.105.68.165:2379
```
#### Manifest (for clusters with RBAC enabled)
```yaml
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
name: external-dns
rules:
- apiGroups: [""]
resources: ["services","endpoints","pods"]
verbs: ["get","watch","list"]
- apiGroups: ["extensions","networking.k8s.io"]
resources: ["ingresses"]
verbs: ["get","watch","list"]
- apiGroups: [""]
resources: ["nodes"]
verbs: ["list"]
---
apiVersion: rbac.authorization.k8s.io/v1beta1
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: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: external-dns
namespace: kube-system
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: external-dns
namespace: kube-system
spec:
strategy:
type: Recreate
selector:
matchLabels:
app: external-dns
template:
metadata:
labels:
app: external-dns
spec:
serviceAccountName: external-dns
containers:
- name: external-dns
image: k8s.gcr.io/external-dns/external-dns:v0.7.3
args:
- --source=ingress
- --provider=coredns
- --log-level=debug # debug only
env:
- name: ETCD_URLS
value: http://10.105.68.165:2379
```
## Enable the ingress controller
You can use the ingress controller in minikube cluster. It needs to enable ingress addon in the cluster.
```
minikube addons enable ingress
```
## Testing ingress example
```
$ cat ingress.yaml
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
name: nginx
annotations:
kubernetes.io/ingress.class: "nginx"
spec:
rules:
- host: nginx.example.org
http:
paths:
- backend:
serviceName: nginx
servicePort: 80
$ kubectl apply -f ingress.yaml
ingress.extensions "nginx" created
```
Wait a moment until DNS has the ingress IP. The DNS service IP is from CoreDNS service. It is "my-coredns-coredns" in this example.
```
$ kubectl get svc my-coredns-coredns
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
my-coredns-coredns ClusterIP 10.100.4.143 <none> 53/UDP 12m
$ kubectl get ingress
NAME HOSTS ADDRESS PORTS AGE
nginx nginx.example.org 10.0.2.15 80 2m
$ kubectl run -it --rm --restart=Never --image=infoblox/dnstools:latest dnstools
If you don't see a command prompt, try pressing enter.
dnstools# dig @10.100.4.143 nginx.example.org +short
10.0.2.15
dnstools#
```