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| -rw-r--r-- | middleware/kubernetes/README.md | 10 | ||||
| -rw-r--r-- | middleware/kubernetes/coredns.yaml.sed | 93 | ||||
| -rwxr-xr-x | middleware/kubernetes/deploy.sh | 19 |
3 files changed, 122 insertions, 0 deletions
diff --git a/middleware/kubernetes/README.md b/middleware/kubernetes/README.md index b64a3b1d0..46237ab2c 100644 --- a/middleware/kubernetes/README.md +++ b/middleware/kubernetes/README.md @@ -128,4 +128,14 @@ all values. The labels that accept wildcards are: * multiple wild cards are allowed in a single query. * e.g. `A` Request `*.*.svc.zone.` or `SRV` request `*.*.*.*.svc.zone.` +## deploy.sh and coredns.yaml.sed +A convenience script to generate a manifest for running CoreDNS on a cluster that is currently +running standard kube-dns. It creates a ConfigMap and a CoreDNS deployment, then updates the +Kube-DNS service selector to use the CoreDNS deployment. It doesn't delete the kube-dns +deployment or replication controller - you'll have to do that manually. + +~~~ +$ ./deploy.sh 10.3.0.0/24 | kubectl apply -f - +$ kubectl delete --namespace=kube-system deployment kube-dns +~~~ diff --git a/middleware/kubernetes/coredns.yaml.sed b/middleware/kubernetes/coredns.yaml.sed new file mode 100644 index 000000000..04f80d64c --- /dev/null +++ b/middleware/kubernetes/coredns.yaml.sed @@ -0,0 +1,93 @@ +apiVersion: v1 +kind: ConfigMap +metadata: + name: coredns + namespace: kube-system +data: + Corefile: | + .:53 { + errors + log stdout + health + kubernetes CLUSTER_DOMAIN { + cidrs SERVICE_CIDR + } + proxy . /etc/resolv.conf + cache 30 + } +--- +apiVersion: extensions/v1beta1 +kind: Deployment +metadata: + name: coredns + namespace: kube-system + labels: + k8s-app: coredns + kubernetes.io/cluster-service: "true" + kubernetes.io/name: "CoreDNS" +spec: + replicas: 1 + selector: + matchLabels: + k8s-app: coredns + template: + metadata: + labels: + k8s-app: coredns + annotations: + scheduler.alpha.kubernetes.io/critical-pod: '' + scheduler.alpha.kubernetes.io/tolerations: '[{"key":"CriticalAddonsOnly", "operator":"Exists"}]' + spec: + containers: + - name: coredns + image: infoblox/coredns:latest + imagePullPolicy: Always + args: [ "-conf", "/etc/coredns/Corefile" ] + volumeMounts: + - name: config-volume + mountPath: /etc/coredns + ports: + - containerPort: 53 + name: dns + protocol: UDP + - containerPort: 53 + name: dns-tcp + protocol: TCP + livenessProbe: + httpGet: + path: /health + port: 8080 + scheme: HTTP + initialDelaySeconds: 60 + timeoutSeconds: 5 + successThreshold: 1 + failureThreshold: 5 + dnsPolicy: Default + volumes: + - name: config-volume + configMap: + name: coredns + items: + - key: Corefile + path: Corefile +--- +apiVersion: v1 +kind: Service +metadata: + name: kube-dns + namespace: kube-system + labels: + k8s-app: coredns + kubernetes.io/cluster-service: "true" + kubernetes.io/name: "CoreDNS" +spec: + selector: + k8s-app: coredns + clusterIP: CLUSTER_DNS_IP + ports: + - name: dns + port: 53 + protocol: UDP + - name: dns-tcp + port: 53 + protocol: TCP diff --git a/middleware/kubernetes/deploy.sh b/middleware/kubernetes/deploy.sh new file mode 100755 index 000000000..d8aade328 --- /dev/null +++ b/middleware/kubernetes/deploy.sh @@ -0,0 +1,19 @@ +#!/bin/bash + +# Deploys CoreDNS to a cluster currently running Kube-DNS. + +SERVICE_CIDR=$1 +CLUSTER_DOMAIN=${2:-cluster.local} +YAML_TEMPLATE=${3:-`pwd`/coredns.yaml.sed} +YAML=${4:-`pwd`/coredns.yaml} + +if [[ -z $SERVICE_CIDR ]]; then + echo "Usage: $0 SERVICE-CIDR [ CLUSTER-DOMAIN ] [ YAML-TEMPLATE ] [ YAML ]" + exit 1 +fi + +CLUSTER_DNS_IP=$(kubectl get service --namespace kube-system kube-dns -o jsonpath="{.spec.clusterIP}") + +sed -e s/CLUSTER_DNS_IP/$CLUSTER_DNS_IP/g -e s/CLUSTER_DOMAIN/$CLUSTER_DOMAIN/g -e s?SERVICE_CIDR?$SERVICE_CIDR?g $YAML_TEMPLATE + + |