set

查看set的帮助

[alvin@k8s1 ~]$ kubectl set -h
Configure application resources

These commands help you make changes to existing application resources.

Available Commands:
  env            Update environment variables on a pod template
  image          Update image of a pod template
  resources      Update resource requests/limits on objects with pod templates
  selector       Set the selector on a resource
  serviceaccount Update ServiceAccount of a resource
  subject        Update User, Group or ServiceAccount in a RoleBinding/ClusterRoleBinding

Usage:
  kubectl set SUBCOMMAND [options]

Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).

set image的帮助

[alvin@k8s1 ~]$ kubectl set image -h
Update existing container image(s) of resources.

Possible resources include (case insensitive):

  pod (po), replicationcontroller (rc), deployment (deploy), daemonset (ds), replicaset (rs)

Examples:
  # Set a deployment's nginx container image to 'nginx:1.9.1', and its busybox container image to 'busybox'.
  kubectl set image deployment/nginx busybox=busybox nginx=nginx:1.9.1

  # Update all deployments' and rc's nginx container's image to 'nginx:1.9.1'
  kubectl set image deployments,rc nginx=nginx:1.9.1 --all

  # Update image of all containers of daemonset abc to 'nginx:1.9.1'
  kubectl set image daemonset abc *=nginx:1.9.1

  # Print result (in yaml format) of updating nginx container image from local file, without hitting the server
  kubectl set image -f path/to/file.yaml nginx=nginx:1.9.1 --local -o yaml

Options:
      --all=false: Select all resources, including uninitialized ones, in the namespace of the specified resource types
      --allow-missing-template-keys=true: If true, ignore any errors in templates when a field or map key is missing in
the template. Only applies to golang and jsonpath output formats.
      --dry-run=false: If true, only print the object that would be sent, without sending it.
  -f, --filename=[]: Filename, directory, or URL to files identifying the resource to get from a server.
      --include-uninitialized=false: If true, the kubectl command applies to uninitialized objects. If explicitly set to
false, this flag overrides other flags that make the kubectl commands apply to uninitialized objects, e.g., "--all".
Objects with empty metadata.initializers are regarded as initialized.
      --local=false: If true, set image will NOT contact api-server but run locally.
  -o, --output='': Output format. One of:
json|yaml|name|template|go-template|go-template-file|templatefile|jsonpath|jsonpath-file.
      --record=false: Record current kubectl command in the resource annotation. If set to false, do not record the
command. If set to true, record the command. If not set, default to updating the existing annotation value only if one
already exists.
  -R, --recursive=false: Process the directory used in -f, --filename recursively. Useful when you want to manage
related manifests organized within the same directory.
  -l, --selector='': Selector (label query) to filter on, not including uninitialized ones, supports '=', '==', and
'!='.(e.g. -l key1=value1,key2=value2)
      --template='': Template string or path to template file to use when -o=go-template, -o=go-template-file. The
template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].

Usage:
  kubectl set image (-f FILENAME | TYPE NAME) CONTAINER_NAME_1=CONTAINER_IMAGE_1 ... CONTAINER_NAME_N=CONTAINER_IMAGE_N
[options]

Use "kubectl options" for a list of global command-line options (applies to all commands).

创建一个deployment和service

[root@k8s1 ~]# kubectl run myapp --image=ikubernetes/myapp:v1 --replicas=2
deployment.apps/myapp created
[root@k8s1 ~]# kubectl expose deployment myapp --name=myapp --port=80
service/myapp exposed
[root@k8s1 ~]# kubectl get svc -l run=myapp
NAME      TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
myapp     ClusterIP   10.108.209.49   <none>        80/TCP    23s

这个时候去访问service,会随机调度到后端的两个pod上去。

我们访问300次，结果是这样的,300次的访问都是version:v1

[alvin@k8s1 ~]$ for i in {1..300};do curl -s 10.108.209.49;done|sort |uniq -c
    300 Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

下面我们就去通过set更新镜像版本

通过set设置镜像版本，实现灰度发布。

更新名为myapp的deployment的镜像为ikubernetes/myapp:v2. （之前是v2）

下面的命令中，deployment后面的myapp是deployment的名字，然后后面的myapp= 这里的myapp是容器的名字，一个pod里面可能有多个容器，所以这里我们能指定容器名。

[alvin@k8s1 ~]$ kubectl set image deployment myapp myapp=ikubernetes/myapp:v2
deployment.extensions/myapp image updated

然后马上执行命令访问servcie查看一下,发现现在的访问结果是有v1,也有v2了，也就是说，通过set更新镜像版本，不会同时更新全部pod，而是新版本和旧版本会同时存在。

[alvin@k8s1 ~]$ for i in {1..300};do curl -s 10.108.209.49;done|sort |uniq -c
    209 Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>
     89 Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

然后再查看一下. 再次访问，300次访问全是v2了，更新完毕，

alvin@k8s1 ~]$ for i in {1..300};do curl -s 10.108.209.49;done|sort |uniq -c
    300 Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

通过rollout查看更新状态

在灰度发布更新镜像的时候，我能也可以查看更新的进度。

下面我们再次更新一下，然后通过rollout status 查看精度

[alvin@k8s1 ~]$ kubectl set image deployment myapp myapp=ikubernetes/myapp:v3
deployment.extensions/myapp image updated
[alvin@k8s1 ~]$ kubectl rollout status deployment myapp
Waiting for deployment "myapp" rollout to finish: 1 out of 2 new replicas have been updated...
Waiting for deployment "myapp" rollout to finish: 1 out of 2 new replicas have been updated...
Waiting for deployment "myapp" rollout to finish: 1 out of 2 new replicas have been updated...
Waiting for deployment "myapp" rollout to finish: 1 old replicas are pending termination...
Waiting for deployment "myapp" rollout to finish: 1 old replicas are pending termination...
deployment "myapp" successfully rolled out

设置每次每次更新多少个

k8s精确地控制着整个发布过程，分批次有序地进行着滚动更新，直到把所有旧的副本全部更新到新版本。实际上，k8s是通过两个参数来精确地控制着每次滚动的pod数量：

• maxSurge 滚动更新过程中运行操作期望副本数的最大pod数，可以为绝对数值(eg：5)，但不能为0；也可以为百分数(eg：10%)。默认为25%。
• maxUnavailable 滚动更新过程中不可用的最大pod数，可以为绝对数值(eg：5)，但不能为0；也可以为百分数(eg：10%)。默认为25%。