K8s之YAML文件

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

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`
[ ~]# 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

[ ~]# mkdir demo
[ ~]# cd demo/
[ 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
[ demo]# kubectl create -f my-nginx.yaml
deployment.apps/my-nginx created

[ 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

[ 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

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

`查看服务`
[ demo]# kubectl get svc
NAME               TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes         ClusterIP   10.0.0.1     <none>        443/TCP        8d
`my-nginx-service   NodePort    10.0.0.210   <none>        80:40377/TCP   20s`
nginx-service      NodePort    10.0.0.242   <none>        80:40422/TCP   33h

1.自动测试命令的正确性，并不执行创建：

[ 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：

[ 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：

[ 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：

[ 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：

[ 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：

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

7.查看字段帮助信息：

[ 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        <string>
     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      <string>
     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    <Object>
     Actions that the management system should take in response to container
     lifecycle events. Cannot be updated.

   livenessProbe        <Object>
     Periodic probe of container liveness. Container will be restarted if the
     probe fails. Cannot be updated. More info:
     https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle#container-probes

   name <string> -required-
     Name of the container specified as a DNS_LABEL. Each container in a pod
     must have a unique name (DNS_LABEL). Cannot be updated.

   ports        <[]Object>
     List of ports to expose from the container. Exposing a port here gives the
     system additional information about the network connections a container
     uses, but is primarily informational. Not specifying a port here DOES NOT
     prevent that port from being exposed. Any port which is listening on the
     default "0.0.0.0" address inside a container will be accessible from the
     network. Cannot be updated.

   readinessProbe       <Object>
     Periodic probe of container service readiness. Container will be removed
     from service endpoints if the probe fails. Cannot be updated. More info:
     https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle#container-probes

   resources    <Object>
     Compute Resources required by this container. Cannot be updated. More info:
     https://kubernetes.io/docs/concepts/configuration/manage-compute-resources-container/

   securityContext      <Object>
     Security options the pod should run with. More info:
     https://kubernetes.io/docs/concepts/policy/security-context/ More info:
     https://kubernetes.io/docs/tasks/configure-pod-container/security-context/

   stdin        <boolean>
     Whether this container should allocate a buffer for stdin in the container
     runtime. If this is not set, reads from stdin in the container will always
     result in EOF. Default is false.

   stdinOnce    <boolean>
     Whether the container runtime should close the stdin channel after it has
     been opened by a single attach. When stdin is true the stdin stream will
     remain open across multiple attach sessions. If stdinOnce is set to true,
     stdin is opened on container start, is empty until the first client
     attaches to stdin, and then remains open and accepts data until the client
     disconnects, at which time stdin is closed and remains closed until the
     container is restarted. If this flag is false, a container processes that
     reads from stdin will never receive an EOF. Default is false

   terminationMessagePath       <string>
     Optional: Path at which the file to which the container‘s termination
     message will be written is mounted into the container‘s filesystem. Message
     written is intended to be brief final status, such as an assertion failure
     message. Will be truncated by the node if greater than 4096 bytes. The
     total message length across all containers will be limited to 12kb.
     Defaults to /dev/termination-log. Cannot be updated.

   terminationMessagePolicy     <string>
     Indicate how the termination message should be populated. File will use the
     contents of terminationMessagePath to populate the container status message
     on both success and failure. FallbackToLogsOnError will use the last chunk
     of container log output if the termination message file is empty and the
     container exited with an error. The log output is limited to 2048 bytes or
     80 lines, whichever is smaller. Defaults to File. Cannot be updated.

   tty  <boolean>
     Whether this container should allocate a TTY for itself, also requires
     ‘stdin‘ to be true. Default is false.

   volumeDevices        <[]Object>
     volumeDevices is the list of block devices to be used by the container.
     This is an alpha feature and may change in the future.

   volumeMounts <[]Object>
     Pod volumes to mount into the container‘s filesystem. Cannot be updated.

   workingDir   <string>
     Container‘s working directory. If not specified, the container runtime‘s
     default will be used, which might be configured in the container image.
     Cannot be updated.