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最近更新时间：2024-07-03 11:23:22
当集群规模增加时，需要保证DNS的稳定、高效；KCE容器服务提供了DNS Autoscale，通过预置的伸缩策略，对DNS执行自动的水平伸缩。
cluster-proportional-autoscaler通过监听集群中可调度节点与核心数量，根据预设的策略来调整目标资源的副本数。您可以通过如下yaml进行部署，来对coredns副本数进行自动扩缩容。
kind: ServiceAccount
apiVersion: v1
metadata:
name: dns-autoscaler
namespace: kube-system
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: system:dns-autoscaler
rules:
- apiGroups: [""]
resources: ["nodes"]
verbs: ["list", "watch"]
- apiGroups: [""]
resources: ["replicationcontrollers/scale"]
verbs: ["get", "update"]
- apiGroups: ["apps"]
resources: ["deployments/scale", "replicasets/scale"]
verbs: ["get", "update"]
- apiGroups: [""]
resources: ["configmaps"]
verbs: ["get", "create"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: system:dns-autoscaler
subjects:
- kind: ServiceAccount
name: dns-autoscaler
namespace: kube-system
roleRef:
kind: ClusterRole
name: system:dns-autoscaler
apiGroup: rbac.authorization.k8s.io
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: dns-autoscaler
namespace: kube-system
labels:
k8s-app: dns-autoscaler
kubernetes.io/cluster-service: "true"
spec:
selector:
matchLabels:
k8s-app: dns-autoscaler
template:
metadata:
labels:
k8s-app: dns-autoscaler
spec:
priorityClassName: system-cluster-critical
securityContext:
seccompProfile:
type: RuntimeDefault
supplementalGroups: [ 65534 ]
fsGroup: 65534
nodeSelector:
kubernetes.io/os: linux
containers:
- name: autoscaler
image: hub.kce.ksyun.com/ksyun/cpa/cluster-proportional-autoscaler:1.8.4
resources:
requests:
cpu: "200m"
memory: "100Mi"
command:
- /cluster-proportional-autoscaler
- --namespace=kube-system
- --configmap=dns-autoscaler
- --nodelabels=type!=virtual-kubelet
- --target=Deployment/coredns
- --default-params={"linear":{"coresPerReplica":64,"nodesPerReplica":8,"min":3,"max":10,"preventSinglePointFailure":true}}
- --logtostderr=true
- --v=9
tolerations:
- key: "CriticalAddonsOnly"
operator: "Exists"
serviceAccountName: dns-autoscaler上述策略使用linear模式进行调整，根据核心数和节点数动态调整副本数，yaml参数中的含义是每64个核心或每8个节点分配一个副本，最小副本数为3，最大副本数为10，以下是具体的配置参数：
{
"coresPerReplica": 64,
"nodesPerReplica": 8,
"min": 3,
"max": 10,
"preventSinglePointFailure": true
}linear模式计算公式如下
replicas = max( ceil( cores * 1/coresPerReplica ) , ceil( nodes * 1/nodesPerReplica ) )
replicas = min(replicas, max)
replicas = max(replicas, min)纯净模式