使用配置清单创建资源
定义pod时使用yaml格式
master ~]# kubectl get pod
NAME READY STATUS RESTARTS AGE client 0/1 Error 0 10d client1 0/1 Completed 0 9d client2 0/1 Error 0 7h13m client3 1/1 Running 0 5h57m myapp-5bc569c47d-5cdpw 1/1 Running 0 3h20m myapp-5bc569c47d-c4gr2 1/1 Running 0 3h20m myapp-5bc569c47d-njr5w 1/1 Running 0 3h20m nginx-deploy-55d8d67cf-hlj9v 1/1 Running 3 10d
master ~]# kubectl get pod myapp-5bc569c47d-5cdpw -o yaml //以yaml格式输出pod信息
apiVersion: v1 //这里的值一般是group/version，这里省略了group名，就表示核心组 kind: Pod //资源类别 metadata: //元数据 creationTimestamp: "2019-06-14T05:32:03Z" generateName: myapp-5bc569c47d- labels: pod-template-hash: 5bc569c47d run: myapp name: myapp-5bc569c47d-5cdpw namespace: default ownerReferences: - apiVersion: apps/v1 blockOwnerDeletion: true controller: true kind: ReplicaSet name: myapp-5bc569c47d uid: bcd43ea4-8e43-11e9-a017-000c29cef804 resourceVersion: "386558" selfLink: /api/v1/namespaces/default/pods/myapp-5bc569c47d-5cdpw uid: bd573709-8e65-11e9-a017-000c29cef804 spec: //规格，即定义接下来所要创建的资源对象所具有的特性，或者满足的规范。可以让用户定义资源对象所处的目标状态 containers: - image: ikubernetes/myapp:v1 imagePullPolicy: IfNotPresent name: myapp resources: {} terminationMessagePath: /dev/termination-log terminationMessagePolicy: File volumeMounts: - mountPath: /var/run/secrets/kubernetes.io/serviceaccount name: default-token-fckpp readOnly: true dnsPolicy: ClusterFirst enableServiceLinks: true nodeName: node01 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-fckpp secret: defaultMode: 420 secretName: default-token-fckpp status: //显示当前资源的当前状态，如果当前状态与目标状态不一致，则需要以目标状态为准 conditions: - lastProbeTime: null lastTransitionTime: "2019-06-14T05:32:03Z" status: "True" type: Initialized - lastProbeTime: null lastTransitionTime: "2019-06-14T05:32:05Z" status: "True" type: Ready - lastProbeTime: null lastTransitionTime: "2019-06-14T05:32:05Z" status: "True" type: ContainersReady - lastProbeTime: null lastTransitionTime: "2019-06-14T05:32:03Z" status: "True" type: PodScheduled containerStatuses: - containerID: docker://0cc8d93c55ee79efe9d7bf4117e1c59db309be4fb498a0486317d33413066d8b image: ikubernetes/myapp:v1 imageID: docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513 lastState: {} name: myapp ready: true restartCount: 0 state: running: startedAt: "2019-06-14T05:32:04Z" hostIP: 192.168.184.142 phase: Running podIP: 10.244.3.9 qosClass: BestEffort startTime: "2019-06-14T05:32:03Z"
创建资源的方法：
apiserver仅接收JSON格式的资源定义；
yaml格式提供配置清单，apiserver可自动将其转为json格式，而后再提交；
大部分资源的配置清单(5个一级字段)：
1、apiServer：group/version 指明创建的资源属于哪个api群组及其版本
master ~]# kubectl api-versions //查看所有版本 admissionregistration.k8s.io/v1beta1 apiextensions.k8s.io/v1beta1 apiregistration.k8s.io/v1 apiregistration.k8s.io/v1beta1 apps/v1 //控制器deployment等属于应用程序管理的核心组资源，属于本组 apps/v1beta1 apps/v1beta2 ........ autoscaling/v1 autoscaling/v2beta1 autoscaling/v2beta2 batch/v1 batch/v1beta1 ....... v1 //主版本，属于核心群组，pod是最核心的资源，属于核心群组，
alpha版：内部测试版 http://www.ttlsa.com/linux/alpha-beta-rc/
beta版：公开测试版
stable版：稳定版
2、kind：资源类别，用来标记创建资源的类型，比如资源是pod或者是deployment或者service等
3、metadata：元数据
name
namespace
labels
annotations
每个资源的引用PATH
/api/GROUP/VERSION/namespaces/NAMESPACE/TYPE/NAME
例如：selfLink: /api/v1/namespaces/default/pods/myapp-5bc569c47d-5cdpw
4、spec：不同的资源类型，它的spec类型是不尽相同的，它是用来定义用户期望的目标状态disired state
5、status：当前状态，current state。本字段由kubernetes集群维护，用户不能删除、定义它
master ~]# kubectl explain pods //pods资源如何定义
KIND: Pod VERSION: v1 DESCRIPTION: Pod is a collection of containers that can run on a host. This resource is created by clients and scheduled onto hosts. FIELDS: apiVersion <string> APIVersion defines the versioned schema of this representation of an object. Servers should convert recognized schemas to the latest internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#resources kind <string> Kind is a string value representing the REST resource this object represents. Servers may infer this from the endpoint the client submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds metadata <Object> Standard object's metadata. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata spec <Object> Specification of the desired behavior of the pod. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status status <Object> Most recently observed status of the pod. This data may not be up to date. Populated by the system. Read-only. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status
查看二级字段如何定义
master ~]# kubectl explain pods.metadata
KIND: Pod 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> //表示映射，由三级组成的映射，映射是另外一种json格式的数组， 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 clusterName <string> ...... creationTimestamp <string> ...... deletionGracePeriodSeconds <integer> ..... deletionTimestamp <string> ...... https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata finalizers <[]string> //前面带有[]，表示是一个列表，字符串类型的数组 Must be empty before the object is deleted from the registry. Each entry is an identifier for the responsible component that will remove the entry from the list. If the deletionTimestamp of the object is non-nil, entries in this list can only be removed. generateName <string> ..... https://git.k8s.io/community/contributors/devel/api-conventions.md#idempotency generation <integer> A sequence number representing a specific generation of the desired state. Populated by the system. Read-only. initializers <Object> //表示可以被嵌套三级字段 .... labels <map[string]string> .... managedFields <[]Object> //是一个对象列表，一个对象由很多字段组成 ManagedFields maps workflow-id and version to the set of fields that are managed by that workflow. This is mostly for internal housekeeping, and users typically shouldn't need to set or understand this field. A workflow can be the user's name, a controller's name, or the name of a specific apply path like "ci-cd". The set of fields is always in the version that the workflow used when modifying the object. This field is alpha and can be changed or removed without notice. name <string> ...... namespace <string> .... ownerReferences <[]Object> .... resourceVersion <string> ..... https://git.k8s.io/community/contributors/devel/api-conventions.md#concurrency-control-and-consistency selfLink <string> SelfLink is a URL representing this object. Populated by the system. Read-only. uid <string> ....
master ~]# kubectl explain pods.spec.containers.livenessProbe //可以查询多级字段定义内容
示例：基于yaml格式的配置文件，定义一个自助式pod资源
[root@master ~]# mkdir manifests
[root@master ~]# cd !$
cd manifests
[root@master manifests]# vim pod-demo.yaml
1 apiVersion: v1 2 kind: Pod 3 metadata: 4 name: pod-demo 5 namespace: default 6 labels: //映射数据可以使用{}，例如labels: {app:myapp, tier:frontend}; 7 app: myapp 8 tier: frontend 9 spec: 10 containers: 11 - name: myapp 12 image: ikubernetes/myapp:v1 13 - name: busybox 14 image: busybox:latest 15 command: //列表数据可以使用[]，例如["/bin/sh","-c","sleep 3600"] 16 - "/bin/sh" 17 - "-c" 18 - "echo $(date) >> /usr/share/nginx/html/index.html; sleep 5"
master manifests]# kubectl create -f pod-demo.yaml //-f表示从文件中加载创建pod
pod/pod-demo created
master manifests]# kubectl get pods //查看运行的pod
NAME READY STATUS RESTARTS AGE client3 1/1 Running 0 10h myapp-5bc569c47d-5cdpw 1/1 Running 0 7h49m myapp-5bc569c47d-c4gr2 1/1 Running 0 7h49m myapp-5bc569c47d-njr5w 1/1 Running 0 7h49m nginx-deploy-55d8d67cf-hlj9v 1/1 Running 3 10d pod-demo 1/2 ImagePullBackOff 0 2m26s //这里由于镜像为下载成功，所以其中一个pod失败
master manifests]# kubectl describe pods pod-demo //pod是类型，pod-demo是名称，先指明资源类型再指明名称，因为资源名称只在类型下唯一