mirror of
https://github.com/notherealmarco/coredns-deployment.git
synced 2025-05-05 12:32:34 +02:00
preferredDuringSchedulingIgnoredDuringExecution cause single node failure in mostly deployment when increasing node one by one by cluster. In most deployment, when one node running coredns is lost, coredns service is outage at least 5mins.Suggest to use **requiredDuringSchedulingIgnoredDuringExecution** instead to avoid single node failure issue. Signed-off-by: Eric <cu.eric.lee@gmail.com>
196 lines
4.2 KiB
YAML
196 lines
4.2 KiB
YAML
apiVersion: v1
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kind: ServiceAccount
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metadata:
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name: coredns
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namespace: kube-system
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRole
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metadata:
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labels:
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kubernetes.io/bootstrapping: rbac-defaults
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name: system:coredns
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rules:
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- apiGroups:
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- ""
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resources:
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- endpoints
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- services
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- pods
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- namespaces
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verbs:
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- list
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- watch
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- apiGroups:
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- discovery.k8s.io
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resources:
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- endpointslices
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verbs:
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- list
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- watch
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRoleBinding
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metadata:
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annotations:
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rbac.authorization.kubernetes.io/autoupdate: "true"
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labels:
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kubernetes.io/bootstrapping: rbac-defaults
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name: system:coredns
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roleRef:
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apiGroup: rbac.authorization.k8s.io
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kind: ClusterRole
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name: system:coredns
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subjects:
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- kind: ServiceAccount
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name: coredns
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namespace: kube-system
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---
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apiVersion: v1
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kind: ConfigMap
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metadata:
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name: coredns
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namespace: kube-system
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data:
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Corefile: |
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.:53 {
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errors
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health {
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lameduck 5s
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}
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ready
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kubernetes CLUSTER_DOMAIN REVERSE_CIDRS {
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fallthrough in-addr.arpa ip6.arpa
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}
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prometheus :9153
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forward . UPSTREAMNAMESERVER {
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max_concurrent 1000
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}
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cache 30
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loop
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reload
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loadbalance
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}STUBDOMAINS
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---
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: coredns
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namespace: kube-system
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labels:
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k8s-app: kube-dns
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kubernetes.io/name: "CoreDNS"
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spec:
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# replicas: not specified here:
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# 1. Default is 1.
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# 2. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
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strategy:
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type: RollingUpdate
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rollingUpdate:
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maxUnavailable: 1
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selector:
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matchLabels:
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k8s-app: kube-dns
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template:
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metadata:
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labels:
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k8s-app: kube-dns
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spec:
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priorityClassName: system-cluster-critical
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serviceAccountName: coredns
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tolerations:
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- key: "CriticalAddonsOnly"
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operator: "Exists"
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nodeSelector:
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kubernetes.io/os: linux
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affinity:
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podAntiAffinity:
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requiredDuringSchedulingIgnoredDuringExecution:
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- labelSelector:
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matchExpressions:
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- key: k8s-app
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operator: In
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values: ["kube-dns"]
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topologyKey: kubernetes.io/hostname
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containers:
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- name: coredns
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image: coredns/coredns:1.8.6
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imagePullPolicy: IfNotPresent
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resources:
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limits:
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memory: 170Mi
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requests:
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cpu: 100m
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memory: 70Mi
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args: [ "-conf", "/etc/coredns/Corefile" ]
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volumeMounts:
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- name: config-volume
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mountPath: /etc/coredns
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readOnly: true
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ports:
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- containerPort: 53
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name: dns
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protocol: UDP
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- containerPort: 53
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name: dns-tcp
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protocol: TCP
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- containerPort: 9153
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name: metrics
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protocol: TCP
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securityContext:
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allowPrivilegeEscalation: false
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capabilities:
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add:
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- NET_BIND_SERVICE
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drop:
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- all
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readOnlyRootFilesystem: true
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livenessProbe:
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httpGet:
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path: /health
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port: 8080
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scheme: HTTP
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initialDelaySeconds: 60
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timeoutSeconds: 5
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successThreshold: 1
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failureThreshold: 5
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readinessProbe:
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httpGet:
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path: /ready
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port: 8181
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scheme: HTTP
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dnsPolicy: Default
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volumes:
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- name: config-volume
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configMap:
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name: coredns
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items:
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- key: Corefile
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path: Corefile
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---
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apiVersion: v1
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kind: Service
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metadata:
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name: kube-dns
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namespace: kube-system
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annotations:
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prometheus.io/port: "9153"
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prometheus.io/scrape: "true"
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labels:
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k8s-app: kube-dns
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kubernetes.io/cluster-service: "true"
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kubernetes.io/name: "CoreDNS"
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spec:
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selector:
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k8s-app: kube-dns
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clusterIP: CLUSTER_DNS_IP
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ports:
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- name: dns
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port: 53
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protocol: UDP
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- name: dns-tcp
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port: 53
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protocol: TCP
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- name: metrics
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port: 9153
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protocol: TCP
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