问Kubernetes安全上下文runAsUser 1000从何而来？

EN

runAsUser: 1001          # hardcode user to non-root if not set in Dockerfile
runAsGroup: 1001         # hardcode group to non-root if not set in Dockerfile
runAsNonRoot: true       # hardcode to non-root. Redundant to above if Dockerfile is set USER 1000

# generic pod spec that's usable inside a deployment or other higher level k8s spec

apiVersion: v1
kind: Pod
metadata:
  name: mypod

spec:

  containers:

      # basic container details
    - name: my-container-name
      # never use reusable tags like latest or stable
      image: my-image:tag
      # hardcode the listening port if Dockerfile isn't set with EXPOSE
      ports:
        - containerPort: 8080
          protocol: TCP

      readinessProbe:        # I always recommend using these, even if your app has no listening ports (this affects any rolling update)
        httpGet:             # Lots of timeout values with defaults, be sure they are ideal for your workload
          path: /ready
          port: 8080
      livenessProbe:         # only needed if your app tends to go unresponsive or you don't have a readinessProbe, but this is up for debate
        httpGet:             # Lots of timeout values with defaults, be sure they are ideal for your workload
          path: /alive
          port: 8080

      resources:             # Because if limits = requests then QoS is set to "Guaranteed"
        limits:
          memory: "500Mi"    # If container uses over 500MB it is killed (OOM)
          #cpu: "2"          # Not normally needed, unless you need to protect other workloads or QoS must be "Guaranteed"
        requests:
          memory: "500Mi"    # Scheduler finds a node where 500MB is available
          cpu: "1"           # Scheduler finds a node where 1 vCPU is available

      # per-container security context
      # lock down privileges inside the container
      securityContext:
        allowPrivilegeEscalation: false # prevent sudo, etc.
        privileged: false               # prevent acting like host root
  
  terminationGracePeriodSeconds: 600 # default is 30, but you may need more time to gracefully shutdown (HTTP long polling, user uploads, etc)

  # per-pod security context
  # enable seccomp and force non-root user
  securityContext:

    seccompProfile:
      type: RuntimeDefault   # enable seccomp and the runtimes default profile

    runAsUser: 1001          # hardcode user to non-root if not set in Dockerfile
    runAsGroup: 1001         # hardcode group to non-root if not set in Dockerfile
    runAsNonRoot: true       # hardcode to non-root. Redundant to above if Dockerfile is set USER 1000