The running kubernetes cluster wants to adjust the network segment address of pod

Running K8S Cluster adjustment Pod The segment address of

1. modify Pod Background of network segment address

Use sealos The deployment of K8S colony , default Pod Network segment is 100.64.0.0/16, There is no problem running in a privatized environment , But when the cluster is deployed in Alibaba cloud ECS In the following , adopt SLB Seven layers of load K8S Applications in the cluster , There will be access exceptions , The packet cannot be returned to SLB, After discussion with Alibaba cloud engineers, I learned ,SLB forwarding Proxy Network segment is 100.64.0.0/16, And K8S Pod The network segment address of conflicts , Thus, abnormal network phenomena may occur .

2. At present K8S Cluster information

[[email protected] ~]# kubectl get nodes
NAME         STATUS   ROLES    AGE     VERSION
k8s-master   Ready    master   6m43s   v1.19.16
k8s-node-1   Ready    <none>   6m13s   v1.19.16
k8s-node-2   Ready    <none>   6m13s   v1.19.16

Current Pod The network segment address is 100 Network segment , We need to adjust it to 10.10.0.0/18.

3. First in K8S Build a cluster Pod

First in K8S Build a cluster Pod, Observe before and after modifying the network segment Pod Is it available .

1） Resource orchestration file

[[email protected]-master k8s]# cat nginx.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        imagePullPolicy: Always
        name: nginx
        ports:
        - containerPort: 80
          name: http
          protocol: TCP
        - containerPort: 443
          name: https
          protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: nginx
  name: nginx-80-443
  namespace: default
spec:
  ports:
  - name: http
    port: 80
    protocol: TCP
    targetPort: 80
  - name: https
    port: 443
    protocol: TCP
    targetPort: 443
  selector:
    app: nginx
  type: NodePort

2） Deploy

[[email protected] k8s]# kubectl get all
NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-6b89b7f467-ct6md   1/1     Running   0          8m32s

NAME                   TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                      AGE
service/kubernetes     ClusterIP   10.96.0.1       <none>        443/TCP                      26m
service/nginx-80-443   NodePort    10.99.243.115   <none>        80:31575/TCP,443:31418/TCP   8m32s

NAME                    READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/nginx   1/1     1            1           8m32s

NAME                               DESIRED   CURRENT   READY   AGE
replicaset.apps/nginx-6b89b7f467   1         1         1       8m32s

4. adjustment K8S Clustered Pod Network segment

4.1. adjustment K8S Network segment of address pool

1. see K8S Default address pool 
[[email protected] k8s]# kubectl get ippool
NAME                  AGE
default-ipv4-ippool   18m

2. Adjust the address range of the address pool 
[[email protected] k8s]# kubectl edit ippool default-ipv4-ippool
  cidr: 10.10.0.0/18

4.2. adjustment Controller-Manager Network segment of component

[[email protected] k8s]# vim /etc/kubernetes/manifests/kube-controller-manager.yaml 
    - --cluster-cidr=10.10.0.0/18

4.4. adjustment Kube-proxy Segment address

[root@k8s-master k8s]# kubectl edit cm kube-proxy -n kube-system
    clusterCIDR: 10.10.0.0/18

4.5. adjustment K8S Cluster all nodes yaml The network segment address in the file

How many Node Just perform the same operation for how many times .

[[email protected] k8s]# kubectl get nodes k8s-master  -o yaml > master.yaml
[[email protected] k8s]# kubectl get nodes k8s-node-1  -o yaml > node-1.yaml
[[email protected] k8s]# kubectl get nodes k8s-node-2  -o yaml > node-2.yaml

[[email protected] k8s]# vim master.yaml
          v:"10.10.0.0/18": {}
spec:
  podCIDR: 10.10.0.0/18
  podCIDRs:
  - 10.10.0.0/18

[root@k8s-master k8s]# kubectl delete node k8s-master
node "k8s-master" deleted
[root@k8s-master k8s]# kubectl apply -f master.yaml 
node/k8s-master created

[root@k8s-master k8s]# kubectl delete node k8s-node-1
node "k8s-node-1" deleted
[root@k8s-master k8s]# kubectl delete node k8s-node-2
node "k8s-node-2" deleted
[root@k8s-master k8s]# kubectl apply -f node-1.yaml 
node/k8s-node-1 created
[root@k8s-master k8s]# kubectl apply -f node-2.yaml 
node/k8s-node-2 created

4.6. All nodes restart kubelet

systemctl restart kubelet

4.7. restart K8S In the cluster Pod

[[email protected] k8s]# kubectl delete pod nginx-6b89b7f467-ct6md
pod "nginx-6b89b7f467-ct6md" deleted

[[email protected] k8s]# kubectl get pod -o wide
NAME                     READY   STATUS    RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES
nginx-6b89b7f467-869m2   1/1     Running   0          23s   10.10.5.129   k8s-node-1   <none>           <none>

Pod The address has been successfully modified .