动态更新POD的节点选择器字段 [英] Update Node Selector field for PODs on the fly

问题描述

这些天来，我一直在尝试围绕k8s做不同的事情.我想知道POD规范中的字段nodeSelector. 据我了解，我们必须为节点分配一些标签，并且这些标签可以在POD规范的nodeSelector字段部分中进一步使用.

I have been trying different things around k8s these days. I am wondering about the field nodeSelector in the POD specification. As I understand we have to assign some labels to the nodes and these labels can further be used in the nodeSelector field part of the POD specification.

基于nodeSelector将节点分配给Pod可以正常工作.但是，在创建Pod之后，现在我想更新/覆盖nodeSelector字段，该字段将根据更新的新nodeSelector标签将我的Pod部署到新节点.

Assignment of the node to pods based on nodeSelector works fine. But, after I create the pod, now I want to update/overwrite the nodeSelector field which would deploy my pod to new node based on new nodeSelector label updated.

我正在以与使用有没有骇客来实现这种情况?

Are there any hacks to achieve such a case ?

如果当前最新版本的kubernetes无法做到这一点，为什么我们不考虑呢?

If this is not possible for the current latest versions of the kubernetes, why should not we consider it ?

谢谢.

推荐答案

虽然按照cookiedough的建议手动编辑部署是一种选择，但我相信使用kubctl patch是更好的解决方案.

While editing deployment manually as cookiedough suggested is one of the options, I believe using kubctl patch would be a better solution.

您可以使用 yaml

You can either patch by using yaml file or JSON string, which makes it easier to integrate thing into scripts. Here is a complete reference.

这是我使用的nginx的简单部署，它将在node-1上创建:

Here's a simple deployment of nginx I used, which will be created on node-1:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80
      nodeSelector:
        kubernetes.io/hostname: node-1

JSON补丁

您可以修补部署以更改所需的节点，如下所示:
kubectl patch deployments nginx-deployment -p '{"spec": {"template": {"spec": {"nodeSelector": {"kubernetes.io/hostname": "node-2"}}}}}'

通过运行kubectl patch deployment nginx-deployment --patch "$(cat patch.yaml)"，其中patch.yaml的准备如下:

By running kubectl patch deployment nginx-deployment --patch "$(cat patch.yaml)", where patch.yaml is prepared as follows:

spec:
  template:
    spec:
      nodeSelector:
        kubernetes.io/hostname: node-2

这两种方法都会导致调度程序在请求的节点上调度新的pod，并在新的pod准备好后立即终止旧的pod.

Both will result in scheduler scheduling new pod on requested node, and terminating the old one as soon as the new one is ready.

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