Kubernetes之Deployment控制器

Deployment 简介

deployment 是用来管理无状态应用的,面向的集群的管理,而不是面向的是一个不可变的个体,举例:有一群鸭子,要吃掉一个,只需要再放一个新的鸭仔就好了,不会影响什么,而有状态的应用,就同时养三条狗一样,而每个狗都是无法代替用新的事物代替的,因为有“感情”这个状态在里面。

Deployment 为Pod 和 ReplicaSet 之上,提供了一个声明式定义(declarative)方法,用来替代以前的ReplicationController 来方便的管理应用。

你只需要在 Deployment 中描述您想要的目标状态是什么,Deployment controller 就会帮您将 Pod 和ReplicaSet 的实际状态改变到您的目标状态。您可以定义一个全新的 Deployment 来

创建 ReplicaSet 或者删除已有的 Deployment 并创建一个新的来替换。也就是说Deployment是可以管理多个ReplicaSet的,如下图:

 

 

典型的应用场景包括:

  • 定义Deployment来创建Pod和ReplicaSet,使用Deployment来创建ReplicaSet。ReplicaSet在后台创建pod。检查启动状态,看它是成功还是失败。
  • 然后,通过更新Deployment的PodTemplateSpec字段来声明Pod的新状态。这会创建一个新的ReplicaSet,Deployment会按照控制的速率将pod从旧的ReplicaSet移动到新d的ReplicaSet中。
  • 如果当前状态不稳定,回滚到之前的Deployment revision。每次回滚都会更新Deployment的revision。
  • 扩容Deployment以满足更高的负载。
  • 暂停Deployment来应用PodTemplateSpec的多个修复,然后恢复上线。
  • 根据Deployment 的状态判断上线是否hang住了。
  • 清除旧的不必要的 ReplicaSet。

 

Deployment 升级

kubectl explain deploy.spec.strategy   策略订是配置怎么滚动升级的,支持两种策略:

  • Recreate   重建式更新,就是删一个建一个。
  • rollingUpdate  滚动更新,简单定义 更新期间pod最多有几个等

rollingUpdate 有两种策略

  • maxSurge  指定超出副本数有几个,两种方式:1、指定数量 2、百分比
  • maxUnavailable 最多有几个不可用

 

Deployment 历史版本

kubectl explain deploy.spec.revisionHistoryLimit

最多保存多少个历史版本,默认是10个

Deployment 模板

kubectl explain deploy.spec.template

通过template 创建我们的目标状态

类似pod的定义(包含 spec 、 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/

   metadata     <Object>
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata

 案例:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deploy
  namespace: default
spec:
  replicas: 2
  selector:
    matchLabels:
      app: myapp
      release: dev
  template:
    metadata:
      labels:
        app: myapp
        release: dev
    spec:
      containers:
      - name: myapp-containers
        image: ikubernetes/myapp:v1
        ports:
        - name: http
          containerPort: 80

结果

看一下deploy 是否成功
$ kubectl get deploy
NAME           DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
myapp-deploy   2         2         2            2           2m
因为deploy 是三层架构 现在会自动启动一个replicasets 我们看一下是否启动
$  kubectl get rs
NAME                     DESIRED   CURRENT   READY     AGE
myapp-deploy-f4bcc4799   2         2         2         5m
我们看自动创建一个rs.名称后面的字符串是 模板的哈希值。是不会发生变化的,最后pod的是随机值
 
我们再看一下最后一层,最后一层为pod
$ kubectl get pods
NAME                           READY     STATUS    RESTARTS   AGE
myapp-deploy-f4bcc4799-cs5xc   1/1       Running   0          7m
myapp-deploy-f4bcc4799-k4tq5   1/1       Running   0          7m

滚动升级案例:

我们通过修改yaml的方式升级

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deploy
  namespace: default
spec:
  replicas: 5
  selector:
    matchLabels:
      app: myapp
      release: dev
  template:
    metadata:
      labels:
        app: myapp
        release: dev
    spec:
      containers:
      - name: myapp-containers
        image: ikubernetes/myapp:v2
        ports:
        - name: http
          containerPort: 80

升级过程(我们看到,是停止一台,升级一台的这种循环。)

kubectl get pods -l app=myapp -w
NAME                           READY     STATUS    RESTARTS   AGE
myapp-deploy-f4bcc4799-cs5xc   1/1       Running   0          23m
myapp-deploy-f4bcc4799-cwzd9   1/1       Running   0         14m
myapp-deploy-f4bcc4799-k4tq5   1/1       Running   0         23m
myapp-deploy-f4bcc4799-shbmb   1/1       Running   0         14m
myapp-deploy-f4bcc4799-vtk6m   1/1       Running   0         14m


myapp-deploy-f4bcc4799-shbmb   1/1       Terminating   0         16m
myapp-deploy-869b888f66-mv5c6   0/1       Pending   0         0s
myapp-deploy-869b888f66-mv5c6   0/1       Pending   0         0s
myapp-deploy-869b888f66-vk9j6   0/1       Pending   0         0s
myapp-deploy-869b888f66-vk9j6   0/1       Pending   0         0s
myapp-deploy-869b888f66-mv5c6   0/1       ContainerCreating   0         0s
myapp-deploy-869b888f66-r57t5   0/1       Pending   0         0s
myapp-deploy-869b888f66-r57t5   0/1       Pending   0         0s
myapp-deploy-869b888f66-vk9j6   0/1       ContainerCreating   0         1s
myapp-deploy-869b888f66-r57t5   0/1       ContainerCreating   0         1s
myapp-deploy-869b888f66-r57t5   0/1       ContainerCreating   0         1s
myapp-deploy-869b888f66-mv5c6   0/1       ContainerCreating   0         1s
myapp-deploy-869b888f66-vk9j6   0/1       ContainerCreating   0         2s
myapp-deploy-f4bcc4799-shbmb   0/1       Terminating   0         16m
myapp-deploy-f4bcc4799-shbmb   0/1       Terminating   0         16m
myapp-deploy-869b888f66-r57t5   1/1       Running   0         4s
myapp-deploy-f4bcc4799-vtk6m   1/1       Terminating   0         16m
myapp-deploy-869b888f66-rxzbb   0/1       Pending   0         1s
myapp-deploy-869b888f66-rxzbb   0/1       Pending   0         1s
myapp-deploy-869b888f66-rxzbb   0/1       ContainerCreating   0         1s
myapp-deploy-869b888f66-vk9j6   1/1       Running   0         5s
myapp-deploy-f4bcc4799-cwzd9   1/1       Terminating   0         16m
myapp-deploy-869b888f66-vvwwv   0/1       Pending   0         0s
myapp-deploy-869b888f66-vvwwv   0/1       Pending   0         0s
.....

我们查看一下 rs的情况 以下可以看到原的rs作为备份,而现在是启动新的rs

$  kubectl get rs -o wide
NAME                      DESIRED   CURRENT   READY     AGE       CONTAINER(S)       IMAGE(S)               SELECTOR
myapp-deploy-869b888f66   5         5         5         3m        myapp-containers   ikubernetes/myapp:v2   app=myapp,pod-template-hash=4256444922,release=dev
myapp-deploy-f4bcc4799    0         0         0         29m       myapp-containers   ikubernetes/myapp:v1   app=myapp,pod-template-hash=906770355,release=dev

 修改滚动升级策略

$ kubectl patch deplop  myapp-deploy -p '{"spec":{"strategy":{"rollingUpdate":{"maxSurge":1,"maxUnavailable":0}}}}'
$  kubectl describe deploy  myapp-deploy
Name:            myapp-deploy
Namespace:        default
CreationTimestamp:    Tue, 28 Aug 2018 09:52:03 -0400
Labels:            app=myapp
            release=dev
Annotations:        deployment.kubernetes.io/revision=4
            kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"name":"myapp-deploy","namespace":"default"},"spec":{"replicas":3,"selector":{...
Selector:        app=myapp,release=dev
Replicas:        3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType:        RollingUpdate
MinReadySeconds:    0
RollingUpdateStrategy:    0 max unavailable, 1 max surge
Pod Template:
....

金丝雀发布

##通过 set image 发布新的镜像 也可以通过yaml文件发布 myapp-containers 是containers 的名称
$ kubectl set image deploy  myapp-deploy myapp-containers=ikubernetes/myapp:v3 && kubectl rollout pause deploy  myapp-deploy
deployment "myapp-deploy" image updated
deployment "myapp-deploy" paused

#查看更新情况(新增加一个资源,但是没执行。是因为pause暂停命令,所以发布一个,这样形成了金丝雀发布,这个金丝雀就是让真实用户验证的)
$ kubectl get pods -l  app=myapp -w 
NAME                            READY     STATUS    RESTARTS   AGE
myapp-deploy-869b888f66-dpwvk   1/1       Running   0          24m
myapp-deploy-869b888f66-frspv   1/1       Running   0         24m
myapp-deploy-869b888f66-sgsll   1/1       Running   0         24m
myapp-deploy-7cbd5b69b9-5s4sq   0/1       Pending   0         0s
myapp-deploy-7cbd5b69b9-5s4sq   0/1       Pending   0         0s
myapp-deploy-7cbd5b69b9-5s4sq   0/1       ContainerCreating   0         1s
myapp-deploy-7cbd5b69b9-5s4sq   0/1       ContainerCreating   0         2s
myapp-deploy-7cbd5b69b9-5s4sq   1/1       Running   0         19s

#那个金丝雀没问题,可以发布后续的更新了
kubectl rollout resume deploy  myapp-deploy

#查看更新情况
 kubectl get pods -l  app=myapp -w 
NAME                            READY     STATUS    RESTARTS   AGE
myapp-deploy-869b888f66-dpwvk   1/1       Running   0          24m
myapp-deploy-869b888f66-frspv   1/1       Running   0         24m
myapp-deploy-869b888f66-sgsll   1/1       Running   0         24m
myapp-deploy-7cbd5b69b9-5s4sq   0/1       Pending   0         0s
myapp-deploy-7cbd5b69b9-5s4sq   0/1       Pending   0         0s
myapp-deploy-7cbd5b69b9-5s4sq   0/1       ContainerCreating   0         1s
myapp-deploy-7cbd5b69b9-5s4sq   0/1       ContainerCreating   0         2s
myapp-deploy-7cbd5b69b9-5s4sq   1/1       Running   0         19s
myapp-deploy-869b888f66-dpwvk   1/1       Terminating   0         31m
myapp-deploy-7cbd5b69b9-p6kzm   0/1       Pending   0         1s
myapp-deploy-7cbd5b69b9-p6kzm   0/1       Pending   0         1s
myapp-deploy-7cbd5b69b9-p6kzm   0/1       ContainerCreating   0         1s
myapp-deploy-7cbd5b69b9-p6kzm   0/1       ContainerCreating   0         2s
myapp-deploy-869b888f66-dpwvk   0/1       Terminating   0         31m
myapp-deploy-869b888f66-dpwvk   0/1       Terminating   0         31m
myapp-deploy-869b888f66-dpwvk   0/1       Terminating   0         31m
myapp-deploy-7cbd5b69b9-p6kzm   1/1       Running   0         18s
myapp-deploy-869b888f66-frspv   1/1       Terminating   0         31m
myapp-deploy-7cbd5b69b9-q8mvs   0/1       Pending   0         0s
myapp-deploy-7cbd5b69b9-q8mvs   0/1       Pending   0         0s
myapp-deploy-7cbd5b69b9-q8mvs   0/1       ContainerCreating   0         0s
myapp-deploy-7cbd5b69b9-q8mvs   0/1       ContainerCreating   0         1s
myapp-deploy-869b888f66-frspv   0/1       Terminating   0         31m
myapp-deploy-869b888f66-frspv   0/1       Terminating   0         31m
myapp-deploy-869b888f66-frspv   0/1       Terminating   0         31m
myapp-deploy-869b888f66-frspv   0/1       Terminating   0         31m

回滚

查看现在有几个版本

 kubectl rollout history deploy  myapp-deploy
deployments "myapp-deploy"
REVISION    CHANGE-CAUSE
0        <none>
3        <none>
4        <none>
5        <none>

回滚到第0版(默认回滚上一版,可以通过 --to-revision指定版本)

$ kubectl rollout undo deploy  myapp-deploy --to-revision=0 
deployment "myapp-deploy" rolled back
#查看回滚情况
$ kubectl get pods -l  app=myapp -w 
NAME                            READY     STATUS    RESTARTS   AGE
myapp-deploy-7cbd5b69b9-5s4sq   1/1       Running   0          6m
myapp-deploy-7cbd5b69b9-p6kzm   1/1       Running   0         1m
myapp-deploy-7cbd5b69b9-q8mvs   1/1       Running   0         54s
^[[Amyapp-deploy-869b888f66-7shh9   0/1       Pending   0         0s
myapp-deploy-869b888f66-7shh9   0/1       Pending   0         0s
myapp-deploy-869b888f66-7shh9   0/1       ContainerCreating   0         0s
myapp-deploy-869b888f66-7shh9   0/1       ContainerCreating   0         1s
myapp-deploy-869b888f66-7shh9   1/1       Running   0         3s
myapp-deploy-7cbd5b69b9-q8mvs   1/1       Terminating   0         5m
myapp-deploy-869b888f66-4l4cv   0/1       Pending   0         0s
myapp-deploy-869b888f66-4l4cv   0/1       Pending   0         0s
myapp-deploy-869b888f66-4l4cv   0/1       ContainerCreating   0         0s
myapp-deploy-869b888f66-4l4cv   0/1       ContainerCreating   0         1s
myapp-deploy-7cbd5b69b9-q8mvs   0/1       Terminating   0         5m
myapp-deploy-869b888f66-4l4cv   1/1       Running   0         2s
myapp-deploy-7cbd5b69b9-p6kzm   1/1       Terminating   0         6m
myapp-deploy-869b888f66-vwgj2   0/1       Pending   0         0s
myapp-deploy-869b888f66-vwgj2   0/1       Pending   0         0s
myapp-deploy-869b888f66-vwgj2   0/1       ContainerCreating   0         0s
myapp-deploy-7cbd5b69b9-q8mvs   0/1       Terminating   0         5m
myapp-deploy-7cbd5b69b9-q8mvs   0/1       Terminating   0         5m
myapp-deploy-7cbd5b69b9-p6kzm   0/1       Terminating   0         6m
myapp-deploy-869b888f66-vwgj2   0/1       ContainerCreating   0         1s
myapp-deploy-869b888f66-vwgj2   1/1       Running   0         3s
myapp-deploy-7cbd5b69b9-5s4sq   1/1       Terminating   0         11m
myapp-deploy-7cbd5b69b9-5s4sq   0/1       Terminating   0         11m
myapp-deploy-7cbd5b69b9-5s4sq   0/1       Terminating   0         11m
myapp-deploy-7cbd5b69b9-p6kzm   0/1       Terminating   0         6m
myapp-deploy-7cbd5b69b9-p6kzm   0/1       Terminating   0         6m
myapp-deploy-7cbd5b69b9-5s4sq   0/1       Terminating   0         11m
myapp-deploy-7cbd5b69b9-5s4sq   0/1       Terminating   0         11m

$ kubectl  get rs -l app=myapp -o wide 
NAME                      DESIRED   CURRENT   READY     AGE       CONTAINER(S)       IMAGE(S)               SELECTOR
myapp-deploy-7cbd5b69b9   0         0         0         14m       myapp-containers   ikubernetes/myapp:v3   app=myapp,pod-template-hash=3768162565,release=dev
myapp-deploy-869b888f66   3         3         3         1h        myapp-containers   ikubernetes/myapp:v2   app=myapp,pod-template-hash=4256444922,release=dev
myapp-deploy-f4bcc4799    0         0         0         1h        myapp-containers   ikubernetes/myapp:v1   app=myapp,pod-template-hash=906770355,release=dev

 

 

kubectl patch 打补丁的方式更新

格式案例(通过json格式)

kubectl patch pod valid-pod -p '{"spec":{"containers":[{"name":"kubernetes-serve-hostname","image":"new image"}]}}'

更新一个images

 kubectl patch  deploy myapp-deploy -p '{"spec":{"template":{"spec":{"containers":[{"name":"myapp-containers","image":"ikubernetes/myapp:v1"}]}}}}'

 

posted @ 2018-08-28 17:48  大胖猴  阅读(20003)  评论(0编辑  收藏  举报