Kubernetes中的Security Context, Resource requirement和Service Account

K8s中的Security Context上下文

k8s中的Security Context通常用于安全考虑，限制pod对host系统文件权限读取或者限制其对系统资源的使用。默认情况下，如果不使用Security Context，则pod默认会以root用户运行，在pod的从天儿中运行程序时，容易对某些对安全要求较高的系统造成损害。

详情参看官方: 

• https://kubernetes.io/docs/tasks/configure-pod-container/security-context/

apiVersion: v1
kind: Pod
Metadata:
  creationTimestamp: null
  labels:
    run: Nginx
  name: Nginx
spec:
  securityContext:
    runAsUser: 100
    runAsGroup: 1000
    fsGroup: 205
  containers:
  - image: Nginx
    name: Nginx
    resources: {}
    volumeMounts:
    - name: host-vol
      mountPath: /etc/local
  dnsPolicy: ClusterFirst
  restartPolicy: Always
  volumes:
  - name: host-vol
    hostPath:
      path: /usr/shared/test
status: {}

 

K8s中的Resource Requirement

Resource资源定义表明了pod在运行期间，占据host资源的请求与限制使用，通常对resources分为requests与limits。字如其面，对系统资源的请求与最大限制

详情参考官方

• https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#resource-requests-and-limits-of-pod-and-container

两种方式可以在pod创建resources

• 命令行

kubectl run Nginx --image=Nginx --ports=80 --restart=Never --requests="cpu=250m,memory=256Mi" --limits="cpu=500m,memory=512Mi"

• YAML文本

apiVersion: v1
kind: Pod
Metadata:
  creationTimestamp: null
  labels:
    run: Nginx
  name: Nginx
spec:
  containers:
  - image: Nginx
    name: Nginx
    resources:
      limits:
        cpu: 500m
        memory: 512Mi
      requests:
        cpu: 250m
        memory: 256Mi
  dnsPolicy: ClusterFirst
  restartPolicy: Never
status: {}

　　

K8s中的Resource Requirement

Service account应用于在pod的容器中运行的进程

详情参看官方：

• https://kubernetes.io/docs/reference/access-authn-authz/service-accounts-admin/
• https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/

同样，有命令行和YAMl文件来定义service account

• 命令行

kubectl create sa Nginx

kubectl run Nginx --image=Nginx --serviceaccount=Nginx --ports=80 --restart=Never

• YAML文件

apiVersion: v1
kind: Pod
Metadata:
  creationTimestamp: null
  labels:
    run: Nginx
  name: Nginx
spec:
  serviceAccountName: Nginx
  containers:
  - image: Nginx
    name: Nginx
  dnsPolicy: ClusterFirst
  restartPolicy: Never
status: {}