k8s-YAML配置文件

一、YAML基础

  YAML是专门用来写配置文件的语言,非常简洁和强大,使用比json更方便。它实质上是一种通用的数据串行化格式。

YAML语法规则:

  • 大小写敏感
  • 使用缩进表示层级关系
  • 缩进时不允许使用Tal键,只允许使用空格
  • 缩进的空格数目不重要,只要相同层级的元素左侧对齐即可
  • ”#” 表示注释,从这个字符一直到行尾,都会被解析器忽略  

在Kubernetes中,只需要知道两种结构类型即可:

  • Lists
  • Maps

  1.1 YAML Maps

  Map顾名思义指的是字典,即一个Key:Value 的键值对信息。例如:  

---
apiVersion: v1
kind: Pod

  注:---为可选的分隔符 ,当需要在一个文件中定义多个结构的时候需要使用。上述内容表示有两个键apiVersion和kind,分别对应的值为v1和Pod。

  Maps的value既能够对应字符串也能够对应一个Maps。例如:  

---
apiVersion: v1
kind: Pod
metadata:
  name: kube100-site
  labels:
    app: web

  注:上述的YAML文件中,metadata这个KEY对应的值为一个Maps,而嵌套的labels这个KEY的值又是一个Map。实际使用中可视情况进行多层嵌套。

  YAML处理器根据行缩进来知道内容之间的关联。上述例子中,使用两个空格作为缩进,但空格的数据量并不重要,只是至少要求一个空格并且所有缩进保持一致的空格数 。例如,name和labels是相同缩进级别,因此YAML处理器知道他们属于同一map;它知道app是lables的值因为app的缩进更大。

  注意:在YAML文件中绝对不要使用tab键

  1.2 YAML Lists

  List即列表,说白了就是数组,例如:  

args
 -beijing
 -shanghai
 -shenzhen
 -guangzhou

  可以指定任何数量的项在列表中,每个项的定义以破折号(-)开头,并且与父元素之间存在缩进。在JSON格式中,表示如下:  

{
  "args": ["beijing", "shanghai", "shenzhen", "guangzhou"]
}

  当然Lists的子项也可以是Maps,Maps的子项也可以是List,例如:  

---
apiVersion: v1
kind: Pod
metadata:
  name: kube100-site
  labels:
    app: web
spec:
  containers:
    - name: front-end
      image: nginx
      ports:
        - containerPort: 80
    - name: flaskapp-demo
      image: jcdemo/flaskapp
      ports: 8080

  如上述文件所示,定义一个containers的List对象,每个子项都由name、image、ports组成,每个ports都有一个KEY为containerPort的Map组成,转成JSON格式文件: 

{
  "apiVersion": "v1",
  "kind": "Pod",
  "metadata": {
        "name": "kube100-site",
        "labels": {
            "app": "web"
        },

  },
  "spec": {
        "containers": [{
            "name": "front-end",
            "image": "nginx",
            "ports": [{
                "containerPort": "80"
            }]
        }, {
            "name": "flaskapp-demo",
            "image": "jcdemo/flaskapp",
            "ports": [{
                "containerPort": "5000"
            }]
        }]
  }
}

二、说明

  • 定义配置时,指定最新稳定版API
  • 配置文件应该存储在集群之外的版本控制仓库中。如果需要,可以快速回滚配置、重新创建和恢复
  • 应该使用YAML格式编写配置文件,而不是json。YAML对用户更加友好
  • 可以将相关对象组合成单个文件,通常会更容易管理
  • 不要没必要指定默认值,简单和最小配置减小错误
  • 在注释中说明一个对象描述更好维护

 

三、使用YAML创建Pod 

---
apiVersion: v1
kind: Pod
metadata:
  name: kube100-site
  labels:
    app: web
spec:
  containers:
    - name: front-end
      image: nginx
      ports:
        - containerPort: 80
    - name: flaskapp-demo
      image: jcdemo/flaskapp
      ports:
        - containerPort: 5000 
  • apiVersion:此处值是v1,这个版本号需要根据安装的Kubernetes版本和资源类型进行变化,记住不是写死的。
  • kind:此处创建的是Pod,根据实际情况,此处资源类型可以是Deployment、Job、Ingress、Service等。
  • metadata:包含Pod的一些meta信息,比如名称、namespace、标签等信息。
  • spe:包括一些container,storage,volume以及其他Kubernetes需要的参数,以及诸如是否在容器失败时重新启动容器的属性。可在特定Kubernetes API找到完整的Kubernetes Pod的属性。

  (1)查看apiVersion 

# 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
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
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1

  (2)下面是一个典型的容器定义: 

…
spec:
  containers:
    - name: front-end
      image: nginx
      ports:
        - containerPort: 80
… 
  • 上述例子只是一个简单的最小定义:一个名字(front-end)、基于nginx的镜像,以及容器将会监听的指定端口号(80)。

  • 除了上述的基本属性外,还能够指定复杂的属性,包括容器启动运行的命令、使用的参数、工作目录以及每次实例化是否拉取新的副本。 还可以指定更深入的信息,例如容器的退出日志的位置。容器可选的设置属性包括:

    name、image、command、args、workingDir、ports、env、resource、volumeMounts、livenessProbe、readinessProbe、livecycle、terminationMessagePath、imagePullPolicy、securityContext、stdin、stdinOnce、tty

  (3)kubectl创建Pod  

# kubectl create -f test_pod.yaml 
pod "kube100-site" created

  (4)查看Pod状态 

# kubectl get pod

NAME                          READY     STATUS    RESTARTS   AGE
kube100-site                  2/2       Running   0          2m

  

 四、创建Deployment

  名词解释 

#test-pod  
apiVersion: v1 #指定api版本,此值必须在kubectl apiversion中    
kind: Pod #指定创建资源的角色/类型    
metadata: #资源的元数据/属性    
  name: test-pod #资源的名字,在同一个namespace中必须唯一    
  labels: #设定资源的标签  
    k8s-app: apache    
    version: v1    
    kubernetes.io/cluster-service: "true"    
  annotations:            #自定义注解列表    
    - name: String        #自定义注解名字    
spec: #specification of the resource content 指定该资源的内容    
  restartPolicy: Always #表明该容器一直运行,默认k8s的策略,在此容器退出后,会立即创建一个相同的容器    
  nodeSelector:     #节点选择,先给主机打标签kubectl label nodes kube-node1 zone=node1    
    zone: node1    
  containers:    
  - name: test-pod #容器的名字    
    image: 10.192.21.18:5000/test/chat:latest #容器使用的镜像地址    
    imagePullPolicy: Never #三个选择Always、Never、IfNotPresent,每次启动时检查和更新(从registery)images的策略,  
                           # Always,每次都检查  
                           # Never,每次都不检查(不管本地是否有)  
                           # IfNotPresent,如果本地有就不检查,如果没有就拉取  
    command: ['sh'] #启动容器的运行命令,将覆盖容器中的Entrypoint,对应Dockefile中的ENTRYPOINT    
    args: ["$(str)"] #启动容器的命令参数,对应Dockerfile中CMD参数    
    env: #指定容器中的环境变量    
    - name: str #变量的名字    
      value: "/etc/run.sh" #变量的值    
    resources: #资源管理  
      requests: #容器运行时,最低资源需求,也就是说最少需要多少资源容器才能正常运行    
        cpu: 0.1 #CPU资源(核数),两种方式,浮点数或者是整数+m,0.1=100m,最少值为0.001核(1m)  
        memory: 32Mi #内存使用量    
      limits: #资源限制    
        cpu: 0.5    
        memory: 1000Mi    
    ports:    
    - containerPort: 80 #容器开发对外的端口  
      name: httpd  #名称  
      protocol: TCP    
    livenessProbe: #pod内容器健康检查的设置  
      httpGet: #通过httpget检查健康,返回200-399之间,则认为容器正常    
        path: / #URI地址    
        port: 80    
        #host: 127.0.0.1 #主机地址    
        scheme: HTTP    
      initialDelaySeconds: 180 #表明第一次检测在容器启动后多长时间后开始    
      timeoutSeconds: 5 #检测的超时时间    
      periodSeconds: 15  #检查间隔时间    
      #也可以用这种方法    
      #exec: 执行命令的方法进行监测,如果其退出码不为0,则认为容器正常    
      #  command:    
      #    - cat    
      #    - /tmp/health    
      #也可以用这种方法    
      #tcpSocket: //通过tcpSocket检查健康     
      #  port: number     
    lifecycle: #生命周期管理    
      postStart: #容器运行之前运行的任务    
        exec:    
          command:    
            - 'sh'    
            - 'yum upgrade -y'    
      preStop:#容器关闭之前运行的任务    
        exec:    
          command: ['service httpd stop']    
    volumeMounts:  #挂载持久存储卷  
    - name: volume #挂载设备的名字,与volumes[*].name 需要对应      
      mountPath: /data #挂载到容器的某个路径下    
      readOnly: True    
  volumes: #定义一组挂载设备    
  - name: volume #定义一个挂载设备的名字    
    #meptyDir: {}    
    hostPath:    
      path: /opt #挂载设备类型为hostPath,路径为宿主机下的/opt,这里设备类型支持很多种  
    #nfs 

  

  (1)创建一个yaml文件  

apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.10
        ports:
        - containerPort: 80

  (2)创建deployment  

[root@master-01 YAML_k8s]# kubectl create -f nginx-deployment.yaml 
deployment.apps "nginx-deployment" created
[root@master-01 YAML_k8s]# kubectl get pod -o  wide
NAME                                READY     STATUS    RESTARTS   AGE       IP              NODE
nginx-deployment-6b7b4d57b4-26wzj   1/1       Running   0          2m        10.20.184.83    master-01
nginx-deployment-6b7b4d57b4-9w7tm   1/1       Running   0          2m        10.20.190.60    node-01
nginx-deployment-6b7b4d57b4-mhh8t   1/1       Running   0          2m        10.20.254.108   node-03
[root@master-01 YAML_k8s]# kubectl get deployment
NAME               DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment   3         3         3            3           2m

  (3)查看标签

[root@master-01 YAML_k8s]# kubectl get pod --show-labels
NAME                                READY     STATUS    RESTARTS   AGE       LABELS
nginx-deployment-6b7b4d57b4-26wzj   1/1       Running   0          3m        app=nginx,pod-template-hash=2636081360
nginx-deployment-6b7b4d57b4-9w7tm   1/1       Running   0          3m        app=nginx,pod-template-hash=2636081360
nginx-deployment-6b7b4d57b4-mhh8t   1/1       Running   0          3m        app=nginx,pod-template-hash=2636081360

  (4)通过标签查找Pod

[root@master-01 YAML_k8s]# kubectl get pod -l app=nginx
NAME                                READY     STATUS    RESTARTS   AGE
nginx-deployment-6b7b4d57b4-26wzj   1/1       Running   0          6m
nginx-deployment-6b7b4d57b4-9w7tm   1/1       Running   0          6m
nginx-deployment-6b7b4d57b4-mhh8t   1/1       Running   0          6m

  (5)deployment创建过程

  Deployment 管理的是replicaset-controller,RC会创建Pod。Pod自身会下载镜像并启动镜像  

[root@master-01 YAML_k8s]# kubectl describe rs nginx-deployment
...
...
...
Events:
  Type    Reason            Age   From                   Message
  ----    ------            ----  ----                   -------
  Normal  SuccessfulCreate  33m   replicaset-controller  Created pod: nginx-deployment-6b7b4d57b4-9w7tm
  Normal  SuccessfulCreate  33m   replicaset-controller  Created pod: nginx-deployment-6b7b4d57b4-26wzj
  Normal  SuccessfulCreate  33m   replicaset-controller  Created pod: nginx-deployment-6b7b4d57b4-mhh8t


[root@master-01 YAML_k8s]# kubectl describe pod nginx-deployment-6b7b4d57b4-26wzj

...
...
...
Events:
  Type    Reason                 Age   From                Message
  ----    ------                 ----  ----                -------
  Normal  Scheduled              36m   default-scheduler   Successfully assigned nginx-deployment-6b7b4d57b4-26wzj to master-01
  Normal  SuccessfulMountVolume  36m   kubelet, master-01  MountVolume.SetUp succeeded for volume "default-token-v5vw9"
  Normal  Pulled                 36m   kubelet, master-01  Container image "nginx:1.10" already present on machine
  Normal  Created                36m   kubelet, master-01  Created container
  Normal  Started                36m   kubelet, master-01  Started container

  (6)升级镜像(nginx1.10-->nginx1.11) 

[root@master-01 YAML_k8s]# kubectl set image deploy/nginx-deployment nginx=nginx:1.11
deployment.apps "nginx-deployment" image updated

[root@master-01 YAML_k8s]# kubectl exec -it nginx-deployment-b96c97dc-2pxjf bash
root@nginx-deployment-b96c97dc-2pxjf:/# nginx -V
nginx version: nginx/1.11.13

  升级镜像的过程是逐步进行的,pod不会一下子全部关闭,而是一个一个升级

   (7)查看发布状态  

[root@master-01 ~]# kubectl rollout status deploy/nginx-deployment
deployment "nginx-deployment" successfully rolled out

  (8)查看deployment历史修订版本  

[root@master-01 ~]# kubectl rollout history deploy/nginx-deployment
deployments "nginx-deployment"
REVISION  CHANGE-CAUSE
1         <none>
2         <none>

# 显示历史有两个版本

[root@master-01 ~]# kubectl rollout history deploy/nginx-deployment --revision=1
deployments "nginx-deployment" with revision #1
Pod Template:
  Labels:	app=nginx
	pod-template-hash=2636081360
  Containers:
   nginx:
    Image:	nginx:1.10
    Port:	80/TCP
    Host Port:	0/TCP
    Environment:	<none>
    Mounts:	<none>
  Volumes:	<none>

[root@master-01 ~]# kubectl rollout history deploy/nginx-deployment --revision=2
deployments "nginx-deployment" with revision #2
Pod Template:
  Labels:	app=nginx
	pod-template-hash=65275387
  Containers:
   nginx:
    Image:	nginx:1.11
    Port:	80/TCP
    Host Port:	0/TCP
    Environment:	<none>
    Mounts:	<none>
  Volumes:	<none>

  (8)编辑deployment  

[root@master-01 ~]# kubectl edit deploy/nginx-deployment


# 将nginx版本改为1.12
...
...
...
   spec:
      containers:
      - image: nginx:1.12
        imagePullPolicy: IfNotPresent
        name: nginx
        ports:
        - containerPort: 80

  升级过程: 

[root@master-01 ~]# kubectl rollout status deploy/nginx-deployment
Waiting for rollout to finish: 1 out of 3 new replicas have been updated...
Waiting for rollout to finish: 1 out of 3 new replicas have been updated...
Waiting for rollout to finish: 1 out of 3 new replicas have been updated...
Waiting for rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for rollout to finish: 1 old replicas are pending termination...
Waiting for rollout to finish: 1 old replicas are pending termination...
deployment "nginx-deployment" successfully rolled out

  (10)扩容/缩容(指定--replicas的数量) 

[root@master-01 ~]# kubectl get pod
NAME                                READY     STATUS    RESTARTS   AGE
nginx-deployment-6b47cf4878-8mjkr   1/1       Running   0          1m
nginx-deployment-6b47cf4878-kr978   1/1       Running   0          1m
nginx-deployment-6b47cf4878-tvhvl   1/1       Running   0          1m
[root@master-01 ~]# kubectl scale deploy/nginx-deployment --replicas=5
deployment.extensions "nginx-deployment" scaled
[root@master-01 ~]# kubectl get pod
NAME                                READY     STATUS              RESTARTS   AGE
nginx-deployment-6b47cf4878-6r5dz   0/1       ContainerCreating   0          4s
nginx-deployment-6b47cf4878-7sjtt   0/1       ContainerCreating   0          4s
nginx-deployment-6b47cf4878-8mjkr   1/1       Running             0          2m
nginx-deployment-6b47cf4878-kr978   1/1       Running             0          2m
nginx-deployment-6b47cf4878-tvhvl   1/1       Running             0          2m

  (11)创建Service提供对外访问的接口 

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
  labels:
    app: nginx
spec:
  ports:
  - port: 88
    targetPort: 80
  selector:
    app: nginx

####
apiVersion: 指定版本

kind: 类型

name: 指定服务名称

labels: 标签

port: Service 服务暴露的端口

targetPort: 容器暴露的端口

seletor: 关联的Pod的标签

  创建service

# kubectl create -f nginx-service.yaml

  查看service(访问Pod是有负载均衡的)

[root@master-01 YAML_k8s]# kubectl get svc/nginx-service
NAME            TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
nginx-service   ClusterIP   10.254.131.176   <none>        88/TCP    1m


# curl 10.254.131.176:88
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

  对service的描述  

# kubectl describe svc/nginx-service
Name:              nginx-service
Namespace:         default
Labels:            app=nginx
Annotations:       <none>
Selector:          app=nginx
Type:              ClusterIP
IP:                10.254.131.176
Port:              <unset>  88/TCP
TargetPort:        80/TCP
Endpoints:         10.20.184.19:80,10.20.184.84:80,10.20.190.62:80 + 2 more...
Session Affinity:  None
Events:            <none

  (12)回滚到以前的版本 

# kubectl rollout history deploy/nginx-deployment
deployments "nginx-deployment"
REVISION  CHANGE-CAUSE
1         <none>
2         <none>
3         <none>

# kubectl rollout history deploy/nginx-deployment --revision=3
deployments "nginx-deployment" with revision #3
Pod Template:
  Labels:	app=nginx
	pod-template-hash=2603790434
  Containers:
   nginx:
    Image:	nginx:1.12
    Port:	80/TCP
    Host Port:	0/TCP
    Environment:	<none>
    Mounts:	<none>
  Volumes:	<none>


# 回滚到上一个版本
# kubectl rollout undo deploy/nginx-deployment
deployment.apps "nginx-deployment"

# 查看版本
# kubectl describe deploy/nginx-deployment
...
...
Labels:  app=nginx
  Containers:
   nginx:
    Image:        nginx:1.11

  (13)回滚到指定版本

# kubectl rollout history deploy/nginx-deployment
deployments "nginx-deployment"
REVISION  CHANGE-CAUSE
1         <none>
3         <none>
4         <none>

# 指定版本
# kubectl rollout undo deploy/nginx-deployment --to-revision=1
deployment.apps "nginx-deployment"

 

posted @ 2018-06-21 13:32  Bigberg  阅读(35198)  评论(0编辑  收藏  举报