官网链接为 https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/#create-a-namespace

操作环境为minikube，需要提前执行下列操作启用metrics-server服务

minikube addons enable metrics-server

使用下列命令可以查看是否开启

kubectl get apiservices | grep metrics

大致流程，原理等需要参考https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/#create-a-namespace 下内容

# 下载一个redis的配置文件

➜ curl -OL https://k8s.io/examples/pods/config/redis-config

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current

                                 Dload  Upload   Total   Spent    Left  Speed

100   185  100   185    0     0     51      0  0:00:03  0:00:03 --:--:--    51

100    43  100    43    0     0     11      0  0:00:03  0:00:03 --:--:--   183

➜ ls

a.dockerfile a.tar        b.tar        redis-config server.js

# 使用kubectl create configmap命令创建一个configmap文件

➜ kubectl create configmap example-redis-config --from-file=redis-config

configmap "example-redis-config" created

# 将configmap文件输出为yaml

➜ kubectl get configmap example-redis-config -o yaml

apiVersion: v1

data:

  redis-config:

    maxmemory 2mb

    maxmemory-policy allkeys-lru

kind: ConfigMap

metadata:

  creationTimestamp: 2019-03-19T08:51:28Z

  name: example-redis-config

  namespace: default

  resourceVersion: "34018"

  selfLink: /api/v1/namespaces/default/configmaps/example-redis-config

  uid: 2f58973b-4a24-11e9-b7b5-080027d6b830

# 根据redis-pod.yaml文件来创建一个pod

➜ kubectl create -f https://k8s.io/examples/pods/config/redis-pod.yaml

pod "redis" created

➜ kubectl get pods

NAME                                 READY     STATUS              RESTARTS   AGE

kubernetes-bootcamp-b4d449bd-vlnpd   1/1       Running             0          1h

redis                                0/1       ContainerCreating   0          36m

# redis-pod.yaml文件的内容如下，可以看到volumes下面的configMap就是来自于上面创建的configMap

# 而configMap来自于最早的redis-config

apiVersion: v1

kind: Pod

metadata:

  name: redis

spec:

  containers:

  - name: redis

    image: kubernetes/redis:v1

    env:

    - name: MASTER

      value: "true"

    ports:

    - containerPort: 6379

    resources:

      limits:

        cpu: "0.1"

    volumeMounts:

    - mountPath: /redis-master-data

      name: data

    - mountPath: /redis-master

      name: config

  volumes:

    - name: data

      emptyDir: {}

    - name: config

      configMap:

        name: example-redis-config

        items:

        - key: redis-config

          path: redis.conf