ACK 1.9已经超出技术支持期限，目前升级管控已经无法适配1.9升级，本文主要指导用户修改1.9的相关配置，使其可以进行升级。
目前主要阻碍是1.9集群内置的DNS服务组件为kube-dns，我们需要将其替换为CoreDNS，就可以使用容器服务提供的升级功能进行升级了。
首先，我们需要在集群中部署CoreDNS服务。注意需要将image修改为您的集群所在的regionid，如你的集群在杭州则将
image: registry-vpc.YOUR-REGIONID.aliyuncs.com/acs/coredns:1.0.6修改为
image: registry-vpc.cn-hangzhou.aliyuncs.com/acs/coredns:1.0.6完整yaml文件如下：
apiVersion: apps/v1
kind: Deployment
metadata:
name: coredns
namespace: kube-system
labels:
k8s-app: kube-dns
spec:
replicas: 2
strategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 1
selector:
matchLabels:
k8s-app: kube-dns
template:
metadata:
labels:
k8s-app: kube-dns
spec:
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- weight: 100
podAffinityTerm:
labelSelector:
matchExpressions:
- key: k8s-app
operator: In
values: ["kube-dns"]
topologyKey: kubernetes.io/hostname
serviceAccountName: coredns
tolerations:
- operator: Exists
nodeSelector:
beta.kubernetes.io/os: linux
containers:
- name: coredns
image: registry-vpc.YOUR-REGIONID.aliyuncs.com/acs/coredns:1.0.6
imagePullPolicy: IfNotPresent
resources:
limits:
memory: 170Mi
requests:
cpu: 100m
memory: 70Mi
args: [ "-conf", "/etc/coredns/Corefile" ]
volumeMounts:
- name: config-volume
mountPath: /etc/coredns
readOnly: true
ports:
- containerPort: 53
name: dns
protocol: UDP
- containerPort: 53
name: dns-tcp
protocol: TCP
- containerPort: 9153
name: metrics
protocol: TCP
livenessProbe:
httpGet:
path: /health
port: 8080
scheme: HTTP
initialDelaySeconds: 60
timeoutSeconds: 5
successThreshold: 1
failureThreshold: 5
securityContext:
allowPrivilegeEscalation: false
capabilities:
add:
- NET_BIND_SERVICE
drop:
- all
readOnlyRootFilesystem: true
dnsPolicy: Default
volumes:
- name: config-volume
configMap:
name: coredns
items:
- key: Corefile
path: Corefile
---
apiVersion: v1
kind: ConfigMap
metadata:
name: coredns
namespace: kube-system
data:
Corefile: |
.:53 {
errors
health
kubernetes cluster.local in-addr.arpa ip6.arpa {
pods insecure
upstream
fallthrough in-addr.arpa ip6.arpa
}
prometheus :9153
proxy . /etc/resolv.conf
cache 30
loadbalance
}
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: system:coredns
rules:
- apiGroups:
- ""
resources:
- endpoints
- services
- pods
- namespaces
verbs:
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: system:coredns
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: system:coredns
subjects:
- kind: ServiceAccount
name: coredns
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: coredns
namespace: kube-system使用该yaml创建CoreDNS服务后，需要观察其是否可以正常运行。
确定CoreDNS正常运行之后，可以逐步减少集群中kube-dns的副本数（spec. replicas）。
最后在确保业务正常运行的前提下，我们可以删掉集群中的kube-dns。
完成上述操作步骤之后，您就可以使用容器服务的集群升级功能进行集群升级了。
如果集群升级之后又出现了kube-dns，您可以将其删除。
