kubernetes资源清单定义入门

Kubernetes资源清单定义

Kubernetes是ReSTful风格的API
GET,PUT,DELETE,POST
kubectl run ,get,edit

资源，对象
workload：Pod，Replicaset，Statefulset，Daemonset，job，Cronjob等
服务发现和负载均衡：service，Ingress..
配置和存储：Volume，CSI
    ConfigMap,Secret
    DownwardAPI
集群级的资源
    Namespace，Node，Role，ClusterRole，RoleBinding(角色绑定)，ClusterRoleBinding(集群角色绑定)
元数据型资源
    HPA，PodTemplate(控制器创建的模板)，LimitRange(资源限制模板)

api群组三个级别：apiversion

内测版

beta 测试版本 公测 （不稳定）

v1 稳定版

一般时候可以使用配置清单来创建
我们来查看一下之前创建的Pod

[root@master ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
client                        1/1       Running   0          11h
myapp-848b5b879b-4xpl7        1/1       Running   0          10h
myapp-848b5b879b-7gtn4        1/1       Running   0          10h
myapp-848b5b879b-xtcdd        1/1       Running   0          10h
nginx-deploy-5b595999-fsxlp   1/1       Running   0          11h

[root@master ~]# kubectl get pod myapp-848b5b879b-4xpl7
NAME                     READY     STATUS    RESTARTS   AGE
myapp-848b5b879b-4xpl7   1/1       Running   0          10h
[root@master ~]# kubectl get pod myapp-848b5b879b-4xpl7 -o yaml
apiVersion: v1
kind: Pod 	#类别
metadata: #嵌套字段
  creationTimestamp: 2018-09-04T17:07:58Z
  generateName: myapp-848b5b879b-
  labels:
    pod-template-hash: "4046164356"
    run: myapp
  name: myapp-848b5b879b-4xpl7
  namespace: default
  ownerReferences:
  - apiVersion: apps/v1
    blockOwnerDeletion: true
    controller: true
    kind: ReplicaSet
    name: myapp-848b5b879b
    uid: 41924f50-b061-11e8-a432-000c29f33006
  resourceVersion: "10899"
  selfLink: /api/v1/namespaces/default/pods/myapp-848b5b879b-4xpl7
  uid: 1259f6af-b065-11e8-a432-000c29f33006
spec:  #非常重要的字段，资源规范
  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-8zzcr
      readOnly: true
  dnsPolicy: ClusterFirst
  nodeName: node1
  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-8zzcr
    secret:
      defaultMode: 420
      secretName: default-token-8zzcr
status:#只读的字段
  conditions:
  - lastProbeTime: null
    lastTransitionTime: 2018-09-04T17:07:57Z
    status: "True"
    type: Initialized
  - lastProbeTime: null
    lastTransitionTime: 2018-09-04T17:07:58Z
    status: "True"
    type: Ready
  - lastProbeTime: null
    lastTransitionTime: null
    status: "True"
    type: ContainersReady
  - lastProbeTime: null
    lastTransitionTime: 2018-09-04T17:07:58Z
    status: "True"
    type: PodScheduled
  containerStatuses:
  - containerID: docker://8e757445c75729e865de6462d7dc4e849909776f8a34657ceab3f11baf569c0d
    image: ikubernetes/myapp:v1
    imageID: docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513
    lastState: {}
    name: myapp
    ready: true
    restartCount: 0
    state:
      running:
        startedAt: 2018-09-04T17:07:58Z
  hostIP: 192.168.68.20
  phase: Running
  podIP: 10.244.1.8
  qosClass: BestEffort
  startTime: 2018-09-04T17:07:57Z

创建资源的方法：
    apiserver仅仅接收JSON格式的资源定义；
    yaml格式提供的配置清单，apiserver可以自动将其转化为json格式，而后在提交

大部分资源的格式清单：
    apiVersion  创建属于哪个群组和哪个版本，注意大小写 kubectl api-versions获取
    
    kind：资源类别

    metadata：元数据
        name
        namespace
        labels  标签
        annotations

        每个资源引用的路径PATH
            /api/GROUP/VERSION/namespaces/NAMESPACE/TYPE/NAME
            大写的替换
    
    spec：期望的状态：disired state

    status：当前状态，current state，本字段有kubernets自己创建，让当前的状态向期望的状态靠近
    查看pod资源如何定义kubectl explain pods

创建第一个yaml文件：一个pod上面创建的两个容器

[root@master manifests]# cat pod-demo.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod-demo
  namespace: default
  labels:
    app: myapp
    tier: frontend
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
  - name: busybox
    image: busybox:latest
    command:
    - "/bin/sh"
    - "-c"
    - "sleep 3600"

开始创建：kubectl create -f pod-demo.yaml

查看自己的创建：kubectl get pod

[root@master manifests]# kubectl get pod
NAME                          READY     STATUS    RESTARTS   AGE
client                        1/1       Running   0          13h
myapp-848b5b879b-4xpl7        1/1       Running   0          12h
myapp-848b5b879b-7gtn4        1/1       Running   0          12h
myapp-848b5b879b-xtcdd        1/1       Running   0          12h
nginx-deploy-5b595999-fsxlp   1/1       Running   0          13h
pod-demo                      2/2       Running   0          1m

删除自己的创建：kubectl delete -f pod-demo.yaml

获取刚创建pod-demo的详细信息：
kubectl describe pods pod-demo

[root@master manifests]# kubectl describe pods pod-demo
Name:               pod-demo  #资源名
Namespace:          default   #名称空间
Priority:           0
PriorityClassName:  
Node:               node2/192.168.68.30 #运行在哪个节点
Start Time:         Wed, 05 Sep 2018 13:33:26 +0800
Labels:             app=myapp  #标签
                    tier=frontend 
Annotations:        
Status:             Running
IP:                 10.244.2.10
Containers:
  myapp:  #第一个容器
    Container ID:   docker://aa6be83a949e31c1935fe607e9238fd3bc64b51bfa851350ea502c31371d07e4
    Image:          ikubernetes/myapp:v1
    Image ID:       docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513
    Port:           
    Host Port:      
    State:          Running
      Started:      Wed, 05 Sep 2018 13:33:26 +0800
    Ready:          True
    Restart Count:  0
    Environment:    
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-8zzcr (ro)
  busybox:  #第二个容器
    Container ID:  docker://942c9ee53afcc890cbd1471877c5ecca238a8eb9de40fd5399bc3bbfd9e42d28
    Image:         busybox:latest
    Image ID:      docker-pullable://busybox@sha256:cb63aa0641a885f54de20f61d152187419e8f6b159ed11a251a09d115fdff9bd
    Port:          
    Host Port:     
    Command:
      /bin/sh
      -c
      sleep 3600
    State:          Running
      Started:      Wed, 05 Sep 2018 13:33:31 +0800
    Ready:          True
    Restart Count:  0
    Environment:    
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-8zzcr (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  default-token-8zzcr:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-8zzcr
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events: #创建的详细信息
  Type    Reason     Age   From               Message
  ----    ------     ----  ----               -------
  Normal  Scheduled  3m    default-scheduler  Successfully assigned default/pod-demo to node2
  Normal  Pulled     3m    kubelet, node2     Container image "ikubernetes/myapp:v1" already present on machine
  Normal  Created    3m    kubelet, node2     Created container
  Normal  Started    3m    kubelet, node2     Started container
  Normal  Pulling    3m    kubelet, node2     pulling image "busybox:latest"
  Normal  Pulled     3m    kubelet, node2     Successfully pulled image "busybox:latest"
  Normal  Created    3m    kubelet, node2     Created container
  Normal  Started    3m    kubelet, node2     Started container

 

查看myapp的访问日志：
[root@master manifests]# curl 10.244.2.10        #ip是上面生成的
Hello MyApp | Version: v1 | Pod Name
[root@master manifests]# kubectl logs pod-demo myapp
10.244.0.0 - - [05/Sep/2018:05:45:35 +0000] "GET / HTTP/1.1" 200 65 "-" "curl/7.29.0" "-"
10.244.0.0 - - [05/Sep/2018:05:45:44 +0000] "GET / HTTP/1.1" 200 65 "-" "curl/7.29.0" "-"


pod创建的监控：
kubectl get pods -w

删除pod-demo项目：
[root@master manifests]# kubectl delete pods pod-demo
pod "pod-demo" deleted
[root@master manifests]# kubectl get pod
NAME                          READY     STATUS    RESTARTS   AGE
client                        1/1       Running   0          13h
myapp-848b5b879b-4xpl7        1/1       Running   0          12h
myapp-848b5b879b-7gtn4        1/1       Running   0          12h
myapp-848b5b879b-xtcdd        1/1       Running   0          12h
nginx-deploy-5b595999-fsxlp   1/1       Running   0          13h

通过kubectl api-versions 可以查看api的版本
[root@master ~]# 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 #公测版本
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
batch/v1
batch/v1beta1
certificates.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