使用kubectl补丁将DNS重写规则添加到CoreDNS Configmap [英] Use kubectl patch to add DNS Rewrite Rule to CoreDNS Configmap

问题描述

我想使用kubectl patch命令将DNS重写规则添加到coredns配置图，如

I want to use the kubectl patch command to add a DNS rewrite rule to the coredns configmap, as described at Custom DNS Entries For Kubernetes. The default config map looks like this:

apiVersion: v1
data:
  Corefile: |
    .:53 {
        log
        errors
        health
        kubernetes cluster.local in-addr.arpa ip6.arpa {
           pods insecure
           upstream
           fallthrough in-addr.arpa ip6.arpa
           ttl 30
        }
        prometheus :9153
        forward . /etc/resolv.conf
        cache 30
        loop
        reload
        loadbalance
    }
kind: ConfigMap
....

我要添加行

rewrite name old.name new.name

，但是如何指定在.:53"中添加一行元素使我感到困惑.

but how to specify adding a line within the ".:53" element is confounding me.

我知道使用kubectl get ... | sed ... | kubectl replace -f -可以获得类似的结果，但这看起来很难看，而且我想使用JSON扩展对kubctl patch的了解.谢谢！

I know that I can get a similar result using kubectl get ... | sed ... | kubectl replace -f - but that would look kind of ugly, plus I want to expand my knowledge of kubctl patch using JSON. Thanks!

推荐答案

您不能使用patch修改ConfigMap.

You cannot modify ConfigMap using patch in your case.

data.Corefile是键，并且其值(Corefile内容)的类型为:string.

data.Corefile is a key and its value (Corefile content) is of type: string.

api-server将其视为字节字符串.您无法使用kubectl补丁来修补字符串的一部分.

It is treated by api-server as a string of bytes. You cannot patch part of a string with kubectl patch.

第二:

我想使用JSON扩展我对kubctl补丁的了解

I want to expand my knowledge of kubctl patch using JSON

Corefile甚至不是有效的json文件.即使是，api-server也看不到json/yaml，对于api-server来说，它只是一串随机的字母数字字符.

Corefile is not even a valid json file. Even if it was, api-server doesn't see a json/yaml, for api-server its just a string of random alphanumeric characters.

那你该怎么办?

您剩下的是kubectl get ... | sed ... | kubectl replace -f - ，这是一个完全有效的解决方案.

You are left with kubectl get ... | sed ... | kubectl replace -f - , and this is a totally valid solution.

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