关于python:python-kubernetes-获取-pod-的-cpu-占用率

这个教程是应用 kubernetes 的 python client sdk 获取 pod 的 cpu 占用率，而不是通过 kubectl 命令！

kubernetes python client sdk

动机

我要做什么？

最近有一个 pod ，是 rabbitmq 的消费者，然而会呈现频繁卡死的状况，所以我须要判断 pod 是不是卡死了，而后重启。

这个判断没有方法通过个别的健康检查发现

判断根据：CPU 应用配额低于20m就认定为卡死，就删除 pod（删除 pod 之后，k8s 会从新一个新的）

技术计划

计划一：应用 shell+kubectl。然而我不喜爱 shell，也不喜爱解析非结构化的输入，所以这个计划就淘汰了

计划二：应用 python + kubernetes sdk。我喜爱 python，而且这样能够输入结构化的数据结构，比方 json，不便我解析，good

所以，我才用计划二！

获取一个『命名空间』下的所有 pod

首先，咱们要列出一个 namespace 上面所有的 pod

相似 kubectl get pod -n vddb

vddb 是 namespace 的 name

from kubernetes.client.models.v1_pod import V1Podfrom kubernetes.client.models.v1_pod_list import V1PodListfrom kubernetes.client.models.v1_object_meta import V1ObjectMetafrom kubernetes import client, configfrom kubernetes.client import ApiClientfrom kubernetes.client.rest import RESTResponsefrom loguru import loggerconfig.load_kube_config()v1 = client.CoreV1Api()namespaced_name = 'vddb'pod_list: V1PodList = v1.list_namespaced_pod(namespaced_name)for pod in pod_list.items:    pod: V1Pod    metadata: V1ObjectMeta = pod.metadata    pod_name = metadata.name

获取一个 pod 的 metrics

列出了 pod name 之后，咱们就是获取 pod 的对应的 metrics，比方应用的 CPU、内存配额

import jsonfrom kubernetes.client.models.v1_pod import V1Podfrom kubernetes.client.models.v1_pod_list import V1PodListfrom kubernetes.client.models.v1_object_meta import V1ObjectMetafrom kubernetes import client, configfrom kubernetes.client import ApiClientfrom kubernetes.client.rest import RESTResponsefrom loguru import loggerconfig.load_kube_config()v1 = client.CoreV1Api()api_client = ApiClient()namespaced_name = 'vddb'pod_list: V1PodList = v1.list_namespaced_pod(namespaced_name)for pod in pod_list.items:    pod: V1Pod    metadata: V1ObjectMeta = pod.metadata    pod_name = metadata.name    rest_response: RESTResponse = api_client.request(        url=api_client.configuration.host +        f'/apis/metrics.k8s.io/v1beta1/namespaces/{namespaced_name}/pods/{pod_name}',        method='GET'    )    _data: str = rest_response.data    data: dict = json.loads(_data)    _cpu: str = data['containers'][0]['usage']['cpu']    cpu = int(int(_cpu.removesuffix('n'))/1000/1000)

响应体的格局如下所示：

{  "kind": "PodMetrics",  "apiVersion": "metrics.k8s.io/v1beta1",  "metadata": {    "name": "svddb-servixxxxxxxxxxxxxxx4b4-bzs84",    "namespace": "vddb",    "selfLink": "/apis/metrics.k8s.io/v1beta1/namespaces/vddb/pods/svddbxxxxxxxxxxxxxxxx-bzs84",    "creationTimestamp": "2022-12-16T14:40:46Z"  },  "timestamp": "2022-12-16T14:40:09Z",  "window": "30s",  "containers": [    {      "name": "svdxxxxxxxxrators",      "usage": { "cpu": "2575748239n", "memory": "1257180Ki" }    }  ]}

留神，这里的 containers 是一个列表

删除 pod

import jsonfrom kubernetes.client.models.v1_pod import V1Podfrom kubernetes.client.models.v1_pod_list import V1PodListfrom kubernetes.client.models.v1_object_meta import V1ObjectMetafrom kubernetes import client, configfrom kubernetes.client import ApiClientfrom kubernetes.client.rest import RESTResponsefrom loguru import loggerconfig.load_kube_config()v1 = client.CoreV1Api()api_client = ApiClient()namespaced_name = 'vddb'pod_list: V1PodList = v1.list_namespaced_pod(namespaced_name)for pod in pod_list.items:    pod: V1Pod    metadata: V1ObjectMeta = pod.metadata    pod_name = metadata.name    rest_response: RESTResponse = api_client.request(        url=api_client.configuration.host +        f'/apis/metrics.k8s.io/v1beta1/namespaces/{namespaced_name}/pods/{pod_name}',        method='GET'    )    _data: str = rest_response.data    data: dict = json.loads(_data)    _cpu: str = data['containers'][0]['usage']['cpu']    cpu = int(int(_cpu.removesuffix('n'))/1000/1000)    if 'svddb-service-generators-server-prod' in pod_name and cpu < 20:        v1.delete_namespaced_pod(pod_name, namespaced_name)

参考教程：
Get cpu and memory usage through in cluster config
Does the library support "kubectl top pod" api?
https://kubernetes.io/docs/tasks/debug/debug-cluster/resource-metrics-pipeline/