kubernets学习之声明式资源管理方法

k8s声明式资源管理办法

声明式资源管理方法依赖于——资源配置清单（yaml/json）

查看资源配置清单的方法

[root@hdss7-21 ~]# kubectl get svc nginx-dp -o yaml -n kube-public

解释资源配置清单

[root@hdss7-21 ~]# kubectl explain service.metadata

创建资源配置清单

vim /root/nginx-ds-svc.yaml

apiVersion: v1
kind: Service
metadata:
  labels:
    app: nginx-ds
  name: nginx-ds
  namespace: default
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: nginx-ds
  # sessionAffinity: None 默认就是none
  type: ClusterIP

创建

[root@hdss7-21 ~]# kubectl create -f nginx-ds-svc.yaml
service/nginx-ds created

[root@hdss7-21 ~]# kubectl get svc -n default
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   192.168.0.1      <none>        443/TCP   14d
nginx-ds     ClusterIP   192.168.17.122   <none>        80/TCP    62s

修改yaml文件，把端口改为8080

[root@hdss7-21 ~]# kubectl delete svc nginx-ds
service "nginx-ds" deleted

[root@hdss7-21 ~]# kubectl apply -f nginx-ds-svc.yaml
service/nginx-ds created

[root@hdss7-21 ~]# kubectl get svc -n default
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
kubernetes   ClusterIP   192.168.0.1      <none>        443/TCP    14d
nginx-ds     ClusterIP   192.168.101.10   <none>        8080/TCP   14s

修改资源配置分为两类

• 在线修改（不推荐，使用该方法没有历史记录）

  [root@hdss7-21 ~]# kubectl edit svc nginx-ds
  
  service/nginx-ds edited
  
  [root@hdss7-21 ~]# kubectl get svc -n default
  NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
  kubernetes   ClusterIP   192.168.0.1      <none>        443/TCP   15d
  nginx-ds     ClusterIP   192.168.101.10   <none>        80/TCP    4m21s
  

  又将8080改为80

• 离线修改(推荐：有历史记录)

  修改对应的yaml文件，并用kubectl apply -f nginx-ds-svc.yaml命令使修改生效。

有些段是默认的，不用全部列出来。

拉取nginx镜像

[root@hdss7-21 ~]# docker login docker.io
[root@hdss7-21 ~]# docker pull xxxxxxxxxxxx/nginx:curl
[root@hdss7-21 ~]# docker images | grep curl
xxxxxxxxxxxx/nginx         curl              6f10e7047510      3 days ago          136MB

[root@hdss7-21 ~]# docker tag 6f10e7047510 harbor.od.com/public/nginx:curl

[root@hdss7-21 ~]# docker images | grep curl
harbor.od.com/public/nginx curl              6f10e7047510      3 days ago          136MB
xxxxxxxxxxxx/nginx         curl              6f10e7047510      3 days ago          136MB

[root@hdss7-21 ~]# docker push harbor.od.com/public/nginx:curl
The push refers to repository [harbor.od.com/public/nginx]
761966e456bc: Pushed 
4258832b2570: Pushed 
683a28d1d7fd: Pushed 
d626a8ad97a1: Pushed 
curl: digest: sha256:094f8762228ad310514b54fde096ee9594741171b33da2deee21d32a612eba76 size: 1160

修改资源配置清单，把v1.7.9改成curl

[root@hdss7-21 ~]# vim nginx-ds.yaml
........
        image: harbor.od.com/public/nginx:curl

[root@hdss7-21 ~]# kubectl apply -f nginx-ds.yaml 
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply daemonset.extensions/nginx-ds configured

[root@hdss7-21 ~]# kubectl get svc nginx-dp -o yaml -n kube-public > nginx-dp-svc.yaml

查看

[root@hdss7-21 ~]# kubectl describe ds nginx-ds
Name:           nginx-ds
Selector:       app=nginx-ds
Node-Selector:  <none>
Labels:         app=nginx-ds
Annotations:    deprecated.daemonset.template.generation: 2
                kubectl.kubernetes.io/last-applied-configuration:
                  {"apiVersion":"extensions/v1beta1","kind":"DaemonSet","metadata":{"annotations":{},"name":"nginx-ds","namespace":"default"},"spec":{"templ...
Desired Number of Nodes Scheduled: 2
Current Number of Nodes Scheduled: 2
Number of Nodes Scheduled with Up-to-date Pods: 0
Number of Nodes Scheduled with Available Pods: 2
Number of Nodes Misscheduled: 0
Pods Status:  2 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:  app=nginx-ds
  Containers:
   my-nginx:
    Image:        harbor.od.com/public/nginx:curl
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Events:           <none>

因此，发现声明式资源管理清单方法，修改参数时，非常方便。

[root@hdss7-21 ~]# kubectl get pods
NAME             READY   STATUS    RESTARTS   AGE
nginx-ds-nmgjn   1/1     Running   1          7d23h
nginx-ds-v7hrn   1/1     Running   1          7d23h

陈述式删除(推荐)，增，查，删方便

[root@hdss7-21 ~]# kubectl delete svc nginx-ds
service "nginx-ds" deleted

kubectl delete -f nginx-dp-svc.yaml

声明式删除，使用delete -f指定一个yaml文件

[root@hdss7-21 ~]# kubectl delete -f nginx-dp-svc.yaml
service "nginx-dp" deleted

[root@hdss7-21 ~]# kubectl get svc 
NAME         TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   192.168.0.1   <none>        443/TCP   15d

[root@hdss7-21 ~]# kubectl get pods -n kube-public
NAME                        READY   STATUS    RESTARTS   AGE
nginx-dp-5dfc689474-k2k8j   1/1     Running   0          22h

[root@hdss7-21 ~]# kubectl get pods nginx-dp-5dfc689474-k2k8j -o yaml -n kube-public
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: "2020-08-17T14:59:06Z"
  generateName: nginx-dp-5dfc689474-
  labels:
    app: nginx-dp
    pod-template-hash: 5dfc689474
  name: nginx-dp-5dfc689474-k2k8j
  namespace: kube-public
  ownerReferences:
  - apiVersion: apps/v1
    blockOwnerDeletion: true
    controller: true
    kind: ReplicaSet
    name: nginx-dp-5dfc689474
    uid: c13ba8c0-38a5-47aa-9937-e9c040d5cff6
  resourceVersion: "1016545"
  selfLink: /api/v1/namespaces/kube-public/pods/nginx-dp-5dfc689474-k2k8j
  uid: dd34958f-d695-4444-976f-c936c2829303
spec:
  containers:
  - image: harbor.od.com/public/nginx:v1.7.9
    imagePullPolicy: IfNotPresent
    name: nginx
    resources: {}
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
    volumeMounts:
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-bqfhp
      readOnly: true
  dnsPolicy: ClusterFirst
  enableServiceLinks: true
  nodeName: hdss7-22.host.com
  priority: 0
  restartPolicy: Always
  schedulerName: default-scheduler
  securityContext: {}
  serviceAccount: default
  serviceAccountName: default
  terminationGracePeriodSeconds: 30
  tolerations:
  - effect: NoExecute
    key: node.kubernetes.io/not-ready
    operator: Exists
    tolerationSeconds: 300
  - effect: NoExecute
    key: node.kubernetes.io/unreachable
    operator: Exists
    tolerationSeconds: 300
  volumes:
  - name: default-token-bqfhp
    secret:
      defaultMode: 420
      secretName: default-token-bqfhp
status:
  conditions:
  - lastProbeTime: null
    lastTransitionTime: "2020-08-17T14:59:06Z"
    status: "True"
    type: Initialized
  - lastProbeTime: null
    lastTransitionTime: "2020-08-17T14:59:08Z"
    status: "True"
    type: Ready
  - lastProbeTime: null
    lastTransitionTime: "2020-08-17T14:59:08Z"
    status: "True"
    type: ContainersReady
  - lastProbeTime: null
    lastTransitionTime: "2020-08-17T14:59:06Z"
    status: "True"
    type: PodScheduled
  containerStatuses:
  - containerID: docker://5fbb01b7f9b984acd1ea862d0aceebc46089100b2b7afe05539d50ed659e75aa
    image: harbor.od.com/public/nginx:v1.7.9
    imageID: docker-pullable://harbor.od.com/public/nginx@sha256:b1f5935eb2e9e2ae89c0b3e2e148c19068d91ca502e857052f14db230443e4c2
    lastState: {}
    name: nginx
    ready: true
    restartCount: 0
    state:
      running:
        startedAt: "2020-08-17T14:59:07Z"
  hostIP: 10.4.7.22
  phase: Running
  podIP: 172.7.22.3
  qosClass: BestEffort
  startTime: "2020-08-17T14:59:06Z"

获取service

[root@hdss7-21 ~]# kubectl get svc -n kube-public
NAME       TYPE        CLUSTER-IP        EXTERNAL-IP   PORT(S)   AGE
nginx-dp   ClusterIP   192.168.222.251   <none>        80/TCP    22h

[root@hdss7-21 ~]# kubectl get svc nginx-dp -o yaml -n kube-public
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: "2020-08-17T15:04:08Z"
  labels:
    app: nginx-dp
  name: nginx-dp
  namespace: kube-public
  resourceVersion: "1016979"
  selfLink: /api/v1/namespaces/kube-public/services/nginx-dp
  uid: 99681724-4920-4d24-9d40-b6b9618d2362
spec:
  clusterIP: 192.168.222.251
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: nginx-dp
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}

查看相关说明(学习yaml最重要的命令是explain)

[root@hdss7-21 ~]# kubectl explain service.metadata
KIND:     Service
VERSION:  v1

RESOURCE: metadata <Object>

DESCRIPTION:
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata

     ObjectMeta is metadata that all persisted resources must have, which
     includes all objects users must create.

FIELDS:
   annotations	<map[string]string>
     Annotations is an unstructured key value map stored with a resource that
     may be set by external tools to store and retrieve arbitrary metadata. They
     are not queryable and should be preserved when modifying objects. More
     info: http://kubernetes.io/docs/user-guide/annotations