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Version: v0.6.0

YurtAppDaemon

背景介绍

在边缘场景中，来自同一区域的边缘节点被分配到同一个节点池中，此时，一般需要在节点池维度部署一些系统组件，例如CoreDNS。 创建节点池时，我们希望自动创建这些系统组件，而无需任何手动操作。

YurtAppDaemon 确保所有或部分节点池以 Deployment 或 StatefulSet 作为模板运行副本。 随着节点池的创建，这些子部署或状态集也被添加到集群中，子部署或状态集的创建/更新由 YurtAppDaemon 控制器实现。 这些子 Deployments 或 Statefulsets 将在节点池 从集群中移除时被回收，删除 YurtAppDaemon CR 将清理它创建的 Deployments 或 StatefulSets。 YurtAppDaemon 的行为类似于 K8S Daemonset，不同之处在于 YurtAppDaemon 从节点池维度自动创建 K8S 工作负载。

img

用户使用：

  • 创建test1节点池
cat <<EOF | kubectl apply -f -


apiVersion: apps.openyurt.io/v1alpha1
kind: NodePool
metadata:
  name: test1
spec:
  selector:
    matchLabels:
      apps.openyurt.io/nodepool: test1
  type: Edge


EOF
  • 创建test2节点池
cat <<EOF | kubectl apply -f -

apiVersion: apps.openyurt.io/v1alpha1
kind: NodePool
metadata:
  name: test2
spec:
  selector:
    matchLabels:
      apps.openyurt.io/nodepool: test2
  type: Edge

EOF
  • 将节点加入到节点池
 kubectl label node cn-beijing.172.23.142.31 apps.openyurt.io/desired-nodepool=test1
 kubectl label node cn-beijing.172.23.142.32 apps.openyurt.io/desired-nodepool=test1

 kubectl label node cn-beijing.172.23.142.34 apps.openyurt.io/desired-nodepool=test2
 kubectl label node cn-beijing.172.23.142.35 apps.openyurt.io/desired-nodepool=test2
  • 创建YurtAppDaemon
cat <<EOF | kubectl apply -f -

apiVersion: apps.openyurt.io/v1alpha1
kind: YurtAppDaemon
metadata:
  name: daemon-1
  namespace: default
spec:
  selector:
    matchLabels:
      app: daemon-1

  workloadTemplate:
    deploymentTemplate:
      metadata:
        labels:
          app: daemon-1
      spec:
        replicas: 1
        selector:
          matchLabels:
            app: daemon-1
        template:
          metadata:
            labels:
              app: daemon-1
          spec:
            containers:
            - image: nginx:1.18.0
              imagePullPolicy: Always
              name: nginx
  nodepoolSelector:
    matchLabels:
      yurtappdaemon.openyurt.io/type: "nginx"

EOF
  • 为test1节点池打标签
kubectl label np test1 yurtappdaemon.openyurt.io/type=nginx

# Check the Deployment
kubectl get deployments.apps

# Check the Deployment nodeselector

# Check the Pod
  • 为test2节点池打标签
kubectl label np test2 yurtappdaemon.openyurt.io/type=nginx

# Check the Deployment
kubectl get deployments.apps

# Check the Deployment nodeselector

# Check the Pod
  • 改变YurtAppDaemon
# Change yurtappdaemon workloadTemplate replicas to 2

# Change yurtappdaemon workloadTemplate image to nginx:1.19.0

# Check the Pod
  • 移除节点池标签
# Remove the nodepool test1 label
kubectl label np test1 yurtappdaemon.openyurt.io/type-

# Check the Deployment

# Check the Pod

# Remove the nodepool test2 label
kubectl label np test2 yurtappdaemon.openyurt.io/type-

# Check the Deployment

# Check the Pod

coredns单元化部署案例

在openyurt里使用YurtAppDaemon+服务拓扑解决dns解析问题

  • 创建节点池
cat <<EOF | kubectl apply -f -


apiVersion: apps.openyurt.io/v1alpha1
kind: NodePool
metadata:
  name: hangzhou
spec:
  selector:
    matchLabels:
      apps.openyurt.io/nodepool: hangzhou
  taints:
    - effect: NoSchedule
      key: node-role.openyurt.io/edge
  type: Edge


EOF
  • 节点池增加标签
kubectl label np hangzhou yurtappdaemon.openyurt.io/type=coredns
  • 部署coredns
cat <<EOF | kubectl apply -f -


apiVersion: apps.openyurt.io/v1alpha1
kind: YurtAppDaemon
metadata:
  name: coredns
  namespace: kube-system
spec:
  selector:
    matchLabels:
       k8s-app: kube-dns
  workloadTemplate:
    deploymentTemplate:
      metadata:
        labels:
          k8s-app: kube-dns
      spec:
        replicas: 2
        selector:
          matchLabels:
            k8s-app: kube-dns
        template:
          metadata:
            labels:
              k8s-app: kube-dns
          spec:
            volumes:
            - name: config-volume
              configMap:
               name: coredns
               items:
               - key: Corefile
                 path: Corefile
                 name: coredns
            dnsPolicy: Default
            serviceAccount: coredns
            serviceAccountName: coredns
            containers:
            - args:
              - -conf
              - /etc/coredns/Corefile
              image: k8s.gcr.io/coredns:1.6.7
              imagePullPolicy: IfNotPresent
              name: coredns
              resources:
                limits:
                  memory: 170Mi
                requests:
                  cpu: 100m
                  memory: 70Mi
              securityContext:
                allowPrivilegeEscalation: false
                capabilities:
                  add:
                  - NET_BIND_SERVICE
                  drop:
                  - all
                readOnlyRootFilesystem: true        
              livenessProbe:
                failureThreshold: 5
                httpGet:
                  path: /health
                  port: 8080
                  scheme: HTTP
                initialDelaySeconds: 60
                periodSeconds: 10
                successThreshold: 1
                timeoutSeconds: 5  
              volumeMounts:
              - mountPath: /etc/coredns
                name: config-volume
                readOnly: true
  nodepoolSelector:
    matchLabels:
      yurtappdaemon.openyurt.io/type: "coredns"

---
apiVersion: v1
kind: Service
metadata:
  namespace: kube-system
  annotations:
    prometheus.io/port: "9153"
    prometheus.io/scrape: "true"
    openyurt.io/topologyKeys: openyurt.io/nodepool
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: KubeDNS
  name: kube-dns
spec:
  clusterIP: __kubernetes-coredns-ip__  ##修改为kubernetes dns service ip
  ports:
  - name: dns
    port: 53
    protocol: UDP
    targetPort: 53
  - name: dns-tcp
    port: 53
    protocol: TCP
    targetPort: 53
  - name: metrics
    port: 9153
    protocol: TCP
    targetPort: 9153
  selector:
    k8s-app: kube-dns
  sessionAffinity: None
  type: ClusterIP   
---
apiVersion: v1
data:
  Corefile: |
    .:53 {
        errors
        health {
           lameduck 5s
        }
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
           pods insecure
           fallthrough in-addr.arpa ip6.arpa
           ttl 30
        }
        prometheus :9153
        forward . /etc/resolv.conf
        cache 30
        loop
        reload
        loadbalance
    }
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: coredns
  namespace: kube-system
  labels:
      kubernetes.io/cluster-service: "true"
      addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
    addonmanager.kubernetes.io/mode: Reconcile
  name: system:coredns
rules:
- apiGroups:
  - ""
  resources:
  - endpoints
  - services
  - pods
  - namespaces
  verbs:
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - get
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
    addonmanager.kubernetes.io/mode: EnsureExists
  name: system:coredns
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:coredns
subjects:
- kind: ServiceAccount
  name: coredns
  namespace: kube-system


EOF