Kubernetes支持YAML和JSON格式创建资源对象

1，JSON格式用于接口之间消息的传递
2，YAML格式用于配置和管理
3，YAML是一种简洁的非标记性语言

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语法格式：

缩进标识层级关系
不支持制表符（tab）缩进，使用空格缩进
通常开头缩进两个空格
字符后缩进一个空格，如冒号，逗号等
“---”表示YAML格式，一个文件的开始
“#”表示注释

`查看应用名称`
[root@master1 ~]# kubectl api-versions
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
apps/v1beta1
apps/v1beta2
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
coordination.k8s.io/v1beta1
events.k8s.io/v1beta1
extensions/v1beta1
networking.k8s.io/v1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1

[root@master1 ~]# mkdir demo
[root@master1 ~]# cd demo/
[root@master1 demo]# vim nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-nginx
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.15.4
        ports:
        - containerPort: 80

#插入内容后按Esc退出插入模式，输入:wq保存退出
[root@master1 demo]# kubectl create -f my-nginx.yaml
deployment.apps/my-nginx created

[root@master1 demo]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
`my-nginx-d55b94fd-kc2gl             1/1     Running   0          47s`
`my-nginx-d55b94fd-tkr42             1/1     Running   0          47s`
nginx-6c94d899fd-8pf48              1/1     Running   0          23h
nginx-deployment-5477945587-f5dsm   1/1     Running   0          22h
nginx-deployment-5477945587-hmgd2   1/1     Running   0          22h
nginx-deployment-5477945587-pl2hn   1/1     Running   0          22h

[root@master1 demo]# vim my-nginx-service.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-nginx-service
  labels:
    app: nginx
spec:
  type: NodePort
  ports:
  - port: 80
    targetPort: 80
  selector:
    app: nginx
#插入内容后按Esc退出插入模式，输入:wq保存退出

[root@master1 demo]# kubectl create -f my-nginx-service.yaml
service/my-nginx-service created

`查看服务`
[root@master1 demo]# kubectl get svc
NAME               TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes         ClusterIP   10.0.0.1             443/TCP        8d
`my-nginx-service   NodePort    10.0.0.210           80:40377/TCP   20s`
nginx-service      NodePort    10.0.0.242           80:40422/TCP   33h

1.自动测试命令的正确性，并不执行创建：

[root@master1 demo]# kubectl run my-nginx --image=nginx --port=80 --replicas=2 --dry-run
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
deployment.apps/my-nginx created (dry run)

2.查看生成yaml格式：

[root@master1 demo]# kubectl run my-nginx --image=nginx --port=80 --replicas=2 --dry-run -o yaml
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    run: my-nginx
  name: my-nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      run: my-nginx
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        run: my-nginx
    spec:
      containers:
      - image: nginx
        name: my-nginx
        ports:
        - containerPort: 80
        resources: {}
status: {}

3.生成yaml模板文件：

[root@master1 demo]# kubectl run my-nginx --image=nginx --port=80 --replicas=2 --dry-run -o yaml > nginx-deploy.yaml
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.

4.导出json格式文件：

[root@master1 demo]# kubectl run my-nginx --image=nginx --port=80 --replicas=2 --dry-run -o json
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
{
    "kind": "Deployment",
    "apiVersion": "apps/v1beta1",
    "metadata": {
        "name": "my-nginx",
        "creationTimestamp": null,
        "labels": {
            "run": "my-nginx"
        }
    },
    "spec": {
        "replicas": 2,
        "selector": {
            "matchLabels": {
                "run": "my-nginx"
            }
        },
        "template": {
            "metadata": {
                "creationTimestamp": null,
                "labels": {
                    "run": "my-nginx"
                }
            },
            "spec": {
                "containers": [
                    {
                        "name": "my-nginx",
                        "image": "nginx",
                        "ports": [
                            {
                                "containerPort": 80
                            }
                        ],
                        "resources": {}
                    }
                ]
            }
        },
        "strategy": {}
    },
    "status": {}
}

5.将现有的资源生成模板导出：

[root@master1 demo]# kubectl get deploy/nginx --export -o yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "2"
  creationTimestamp: null
  generation: 1
  labels:
    run: nginx
  name: nginx
  selfLink: /apis/extensions/v1beta1/namespaces/default/deployments/nginx
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 2
  selector:
    matchLabels:
      run: nginx
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        run: nginx
    spec:
      containers:
      - image: nginx:1.14
        imagePullPolicy: Always
        name: nginx
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      DNSPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30
status: {}

6.保存到文件中：

[root@master1 demo]# kubectl get deploy/nginx --export -o yaml > my-deploy.yaml

7.查看字段帮助信息：

[root@master1 demo]# kubectl explain pods.spec.containers
KIND:     Pod
VERSION:  v1

RESOURCE: containers <[]Object>

DESCRIPTION:
     List of containers belonging to the pod. Containers cannot currently be
     added or removed. There must be at least one container in a Pod. Cannot be
     updated.

     A single application container that you want to run within a pod.

FIELDS:
   args <[]string>
     Arguments to the entrypoint. The docker image's CMD is used if this is not
     provided. Variable references $(VAR_NAME) are expanded using the
     container's environment. If a variable cannot be resolved, the reference in
     the input string will be unchanged. The $(VAR_NAME) syntax can be escaped
     with a double $$, ie: $$(VAR_NAME). Escaped references will never be
     expanded, regardless of whether the variable exists or not. Cannot be
     updated. More info:
     https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#running-a-command-in-a-shell

   command      <[]string>
     Entrypoint array. Not executed within a shell. The docker image's
     ENTRYPOINT is used if this is not provided. Variable references $(VAR_NAME)
     are expanded using the container's environment. If a variable cannot be
     resolved, the reference in the input string will be unchanged. The
     $(VAR_NAME) syntax can be escaped with a double $$, ie: $$(VAR_NAME).
     Escaped references will never be expanded, regardless of whether the
     variable exists or not. Cannot be updated. More info:
     https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#running-a-command-in-a-shell

   env  <[]Object>
     List of environment variables to set in the container. Cannot be updated.

   envFrom      <[]Object>
     List of sources to populate environment variables in the container. The
     keys defined within a source must be a C_IDENTIFIER. All invalid keys will
     be reported as an event when the container is starting. When a key exists
     in multiple sources, the value associated with the last source will take
     precedence. Values defined by an Env with a duplicate key will take
     precedence. Cannot be updated.

   image        
     Docker image name. More info:
     https://kubernetes.io/docs/concepts/containers/images This field is
     optional to allow higher level config management to default or override
     container images in workload controllers like Deployments and StatefulSets.

   imagePullPolicy      
     Image pull policy. One of Always, Never, IfNotPresent. Defaults to Always
     if :latest tag is specified, or IfNotPresent otherwise. Cannot be updated.
     More info:
     https://kubernetes.io/docs/concepts/containers/images#updating-images

   lifecycle