K8s: 在Pod里面对容器进行配额管理和相关原理

Pod里面对容器进行配额管理

在生产环境中，内存占用通常很大，如果里面有死循环，会导致内存和cpu过大导致影响其他pod运行资源
需要让资源在受控的环境下运行，一般都是加上 resources limits 的配置才能达到最佳实践
默认cpu是0.5个cpu, 一般定义的时候参数是最高的门槛，不会超过这个设置
创建一个命名空间，以便将本练习中创建的资源与集群的其余部分资源隔离
- $ kubectl create namespace cpu-stress

创建 cpu-limit.yaml

apiVersion: v1
kind: Pod
metadata:
  name: cpu-stress-demo
  namespace: cpu-stress
  labels:
    name: cpu-stress-demo
spec:
  containers:
  - name: nginx-stress
    image: registry.cn-beijing.aliyuncs.com/qingfeng666/stress
    args:
      - -cpus
      - "2"  # 指定使用2个CPU核心进行压力测试
    resources:
      limits:
        cpu: "1"  # 设置CPU上限为1个核心
      requests:
        cpu: "0.5"  # 设置CPU请求为0.5个核心（可选，根据集群策略设置）
  restartPolicy: Never  # 设置重启策略为Never，因为这是一个一次性任务

$ kubectl create -f cpu-limit.yaml
```
pod/cpu-stress-demo created
```

$ kubectl get po -n cpu-stress -w

NAME              READY   STATUS    RESTARTS   AGE
cpu-stress-demo   1/1     Running   0          7s

$ kubectl get po cpu-stress-demo -n cpu-stress -o yaml

apiVersion: v1
items:
- apiVersion: v1
  kind: Pod
  metadata:
    creationTimestamp: "2024-04-18T22:34:13Z"
    labels:
      name: cpu-stress-demo
    name: cpu-stress-demo
    namespace: cpu-stress
    resourceVersion: "81301"
    uid: f423a147-4bac-4f82-a791-0e851d67366c
  spec:
    containers:
    - args:
      - -cpus
      - "2"
      image: registry.cn-beijing.aliyuncs.com/qingfeng666/stress
      imagePullPolicy: Always
      name: nginx-stress
      resources:
        limits:
          cpu: "1"
        requests:
          cpu: 500m
      terminationMessagePath: /dev/termination-log
      terminationMessagePolicy: File
      volumeMounts:
      - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
        name: kube-api-access-mg68j
        readOnly: true
    dnsPolicy: ClusterFirst
    enableServiceLinks: true
    nodeName: node2.k8s
    preemptionPolicy: PreemptLowerPriority
    priority: 0
    restartPolicy: Never
    schedulerName: default-scheduler
    securityContext: {}
    serviceAccount: default
    serviceAccountName: default
    terminationGracePeriodSeconds: 30
    tolerations:
    - effect: NoExecute
      key: node.kubernetes.io/not-ready
      operator: Exists
      tolerationSeconds: 300
    - effect: NoExecute
      key: node.kubernetes.io/unreachable
      operator: Exists
      tolerationSeconds: 300
    volumes:
    - name: kube-api-access-mg68j
      projected:
        defaultMode: 420
        sources:
        - serviceAccountToken:
            expirationSeconds: 3607
            path: token
        - configMap:
            items:
            - key: ca.crt
              path: ca.crt
            name: kube-root-ca.crt
        - downwardAPI:
            items:
            - fieldRef:
                apiVersion: v1
                fieldPath: metadata.namespace
              path: namespace
  status:
    conditions:
    - lastProbeTime: null
      lastTransitionTime: "2024-04-18T22:34:13Z"
      status: "True"
      type: Initialized
    - lastProbeTime: null
      lastTransitionTime: "2024-04-18T22:34:16Z"
      status: "True"
      type: Ready
    - lastProbeTime: null
      lastTransitionTime: "2024-04-18T22:34:16Z"
      status: "True"
      type: ContainersReady
    - lastProbeTime: null
      lastTransitionTime: "2024-04-18T22:34:13Z"
      status: "True"
      type: PodScheduled
    containerStatuses:
    - containerID: docker://12668f59353306dda08a395bf7dd36c0eae699b0ed1350ec96b8ffc3705b6a5e
      image: registry.cn-beijing.aliyuncs.com/qingfeng666/stress:latest
      imageID: docker-pullable://registry.cn-beijing.aliyuncs.com/qingfeng666/stress@sha256:155d7266cb7ed6fecd34b2e4f8a25c2b21eb77723658fb4ab2db630d41118c7d
      lastState: {}
      name: nginx-stress
      ready: true
      restartCount: 0
      started: true
      state:
        running:
          startedAt: "2024-04-18T22:34:15Z"
    hostIP: 10.211.55.12
    phase: Running
    podIP: 10.244.2.12
    podIPs:
    - ip: 10.244.2.12
    qosClass: Burstable
    startTime: "2024-04-18T22:34:13Z"
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""