-如何使用资源定义？

Question

使用下面的yml文件：

apiVersion: v1
kind: Pod
metadata:
  name: my-nginx
spec:
  containers:
  - name: my-nginx
    image: nginx:alpine

在运行kubectl create -f nginx.pod.yml --save-config时，按照文档：If true, the configuration of current object will be saved in its annotation.的规定

这个注释到底保存在哪里？如何查看此注释？

Answer 1

下面的命令将打印pod my-nginx中的所有注释

kubectl get pod my-nginx  -o jsonpath='{.metadata.annotations}'

在上述输出的kubectl.kubernetes.io/last-applied-configuration下，将存储所使用的配置。

下面是一个显示用法的示例：

我部署的原始清单：

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: my-deploy
  name: my-deploy
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-deploy
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: my-deploy
    spec:
      containers:
      - image: nginx
        name: nginx
        resources: {}
status: {}

按照以下方式创建了部署：

k create  -f x.yml --save-config
deployment.apps/my-deploy created

kubectl get deployments.apps my-deploy   -o jsonpath='{.metadata.annotations.kubectl\.kubernetes\.io\/last-applied-configuration}' |jq .
{
  "apiVersion": "apps/v1",
  "kind": "Deployment",
  "metadata": {
    "annotations": {},
    "creationTimestamp": null,
    "labels": {
      "app": "my-deploy"
    },
    "name": "my-deploy",
    "namespace": "default"
  },
  "spec": {
    "replicas": 1,
    "selector": {
      "matchLabels": {
        "app": "my-deploy"
      }
    },
    "strategy": {},
    "template": {
      "metadata": {
        "creationTimestamp": null,
        "labels": {
          "app": "my-deploy"
        }
      },
      "spec": {
        "containers": [
          {
            "image": "nginx",
            "name": "nginx",
            "resources": {}
          }
        ]
      }
    }
  },
  "status": {}
}

kubectl get deployments.apps my-deploy   -o jsonpath='{.spec.template.spec.containers[*].image}'
nginx

现在，一些用户来到这里，使用nginx命令将nginx上的图像从httpd更改为imperative。

k set image deployment/my-deploy nginx=httpd --record
deployment.apps/my-deploy image updated


kubectl get deployments.apps my-deploy   -o jsonpath='{.spec.template.spec.containers[*].image}'
httpd

但是，我们可以检查最后一次应用的声明性配置是否更新。

kubectl get deployments.apps my-deploy   -o jsonpath='{.metadata.annotations.kubectl\.kubernetes\.io\/last-applied-configuration}' |jq .
{
  "apiVersion": "apps/v1",
  "kind": "Deployment",
  "metadata": {
    "annotations": {},
    "creationTimestamp": null,
    "labels": {
      "app": "my-deploy"
    },
    "name": "my-deploy",
    "namespace": "default"
  },
  "spec": {
    "replicas": 1,
    "selector": {
      "matchLabels": {
        "app": "my-deploy"
      }
    },
    "strategy": {},
    "template": {
      "metadata": {
        "creationTimestamp": null,
        "labels": {
          "app": "my-deploy"
        }
      },
      "spec": {
        "containers": [
          {
            "image": "nginx",
            "name": "nginx",
            "resources": {}
          }
        ]
      }
    }
  },
  "status": {}
}

现在，将原始清单文件中的图像名称从nginx更改为flask，然后执行kubectl apply(声明性命令)。

kubectl apply -f orig.yml
deployment.apps/my-deploy configured
kubectl get deployments.apps my-deploy   -o jsonpath='{.spec.template.spec.containers[*].image}'
flask

现在检查最后一个应用配置注释，它将包含flask。请记住，当使用kubectl set image命令时，它是丢失的。

kubectl get deployments.apps my-deploy   -o jsonpath='{.metadata.annotations.kubectl\.kubernetes\.io\/last-applied-configuration}' |jq .
{
  "apiVersion": "apps/v1",
  "kind": "Deployment",
  "metadata": {
    "annotations": {},
    "creationTimestamp": null,
    "labels": {
      "app": "my-deploy"
    },
    "name": "my-deploy",
    "namespace": "default"
  },
  "spec": {
    "replicas": 1,
    "selector": {
      "matchLabels": {
        "app": "my-deploy"
      }
    },
    "strategy": {},
    "template": {
      "metadata": {
        "creationTimestamp": null,
        "labels": {
          "app": "my-deploy"
        }
      },
      "spec": {
        "containers": [
          {
            "image": "flask",
            "name": "nginx",
            "resources": {}
          }
        ]
      }
    }
  },
  "status": {}
}

保存的“上次应用”注释在哪里：

与其他所有内容一样，它保存在etcd中，使用问题中提供的清单创建结荚，并运行raw etcd命令打印内容。(在这个dev环境中，etcd没有加密)。

ETCDCTL_API=3 etcdctl --cert /etc/kubernetes/pki/apiserver-etcd-client.crt --key /etc/kubernetes/pki/apiserver-etcd-client.key --cacert /etc/kubernetes/pki/etcd/ca.crt get /registry/pods/default/my-nginx
/registry/pods/default/my-nginx
k8s

v1Pod⚌
⚌
                                                                                                                                                                   my-nginxdefault"*$a3s4b729-c96a-40f7-8de9-5d5f4ag21gfa2⚌⚌⚌b⚌
0kubectl.kubernetes.io/last-applied-configuration⚌{"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"name":"my-nginx","namespace":"default"},"spec":{"containers":[{"image":"nginx:alpine","name":"my-nginx"}]}}