kubernetes: Reverse zone fall through (#53)

* add cidr default, move to  getopts

* add ipv6 zone

* update readme

kubernetes/README.md

@@ -21,10 +21,10 @@ You should examine the manifest carefully and make sure it is correct for your p
 cluster. Depending on how you have built your cluster and the version you are running,
 some modifications to the manifest may be needed.
 
-In the best case scenario, all that's needed to replace Kube-DNS are these two commands (replacing the CIDRs with the service and pod CIDRs in your deployment respectively):
+In the best case scenario, all that's needed to replace Kube-DNS are these two commands:
 
 ~~~
-$ ./deploy.sh 10.3.0.0/12 172.17.0.0/16 | kubectl apply -f -
+$ ./deploy.sh | kubectl apply -f -
 $ kubectl delete --namespace=kube-system deployment kube-dns
 ~~~
 

kubernetes/coredns.yaml.sed

@@ -49,9 +49,10 @@ data:
     .:53 {
         errors
         health
-        kubernetes CLUSTER_DOMAIN SERVICE_CIDR POD_CIDR {
+        kubernetes CLUSTER_DOMAIN REVERSE_CIDRS {
           pods insecure
           upstream /etc/resolv.conf
+          fallthrough in-addr.arpa ip6.arpa
         }
         prometheus :9153
         proxy . /etc/resolv.conf

kubernetes/deploy.sh

@@ -2,23 +2,51 @@
 
 # Deploys CoreDNS to a cluster currently running Kube-DNS.
 
-SERVICE_CIDR=$1
+show_help () {
-POD_CIDR=$2
+cat << USAGE
-CLUSTER_DNS_IP=$3
+usage: $0 [ -r REVERSE-CIDR ] [ -i DNS-IP ] [ -d CLUSTER-DOMAIN ] [ -t YAML-TEMPLATE ]
-CLUSTER_DOMAIN=${4:-cluster.local}
-YAML_TEMPLATE=${5:-`pwd`/coredns.yaml.sed}
 
-if [[ -z $SERVICE_CIDR ]]; then
+    -r : Define a reverse zone for the given CIDR. You may specifcy this option more
-	echo "Usage: $0 SERVICE-CIDR [ POD-CIDR ] [ DNS-IP ] [ CLUSTER-DOMAIN ] [ YAML-TEMPLATE ]"
+         than once to add multiple reverse zones. If no reverse CIDRs are defined,
-	exit 1
+         then the default is to handle all reverse zones (i.e. in-addr.arpa and ip6.arpa)
+    -i : Specify the cluster DNS IP address. If not specificed, the IP address of
+         the existing "kube-dns" service is used, if present.
+USAGE
+exit 0
+}
+
+# Simple Defaults
+CLUSTER_DOMAIN=cluster.local
+YAML_TEMPLATE=`pwd`/coredns.yaml.sed
+
+
+# Get Opts
+while getopts "hr:i:d:t:" opt; do
+    case "$opt" in
+    h)  show_help
+        ;;
+    r)  REVERSE_CIDRS="$REVERSE_CIDRS $OPTARG"
+        ;;
+    i)  CLUSTER_DNS_IP=$OPTARG
+        ;;
+    d)  CLUSTER_DOMAIN=$OPTARG
+        ;;
+    t)  YAML_TEMPLATE=$OPTARG
+        ;;
+    esac
+done
+
+# Conditional Defaults
+if [[ -z $REVERSE_CIDRS ]]; then
+  REVERSE_CIDRS="in-addr.arpa ip6.arpa"
 fi
-
 if [[ -z $CLUSTER_DNS_IP ]]; then
+  # Default IP to kube-dns IP
   CLUSTER_DNS_IP=$(kubectl get service --namespace kube-system kube-dns -o jsonpath="{.spec.clusterIP}")
   if [ $? -ne 0 ]; then
-      >&2 echo "Error! The IP address for DNS service couldn't be determined automatically. Please specify the DNS-IP in paramaters."
+      >&2 echo "Error! The IP address for DNS service couldn't be determined automatically. Please specify the DNS-IP with the '-i' option."
       exit 2
   fi
 fi
 
-sed -e s/CLUSTER_DNS_IP/$CLUSTER_DNS_IP/g -e s/CLUSTER_DOMAIN/$CLUSTER_DOMAIN/g -e s?SERVICE_CIDR?$SERVICE_CIDR?g -e s?POD_CIDR?$POD_CIDR?g $YAML_TEMPLATE
+sed -e s/CLUSTER_DNS_IP/$CLUSTER_DNS_IP/g -e s/CLUSTER_DOMAIN/$CLUSTER_DOMAIN/g -e "s?REVERSE_CIDRS?$REVERSE_CIDRS?g" $YAML_TEMPLATE