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In Kubernetes (K8s),requestandlimitThese are two important concepts used to control and manage container resource usage.

1. Request：
   • requestDefines the minimum amount of resources that need to be guaranteed when the container starts. This means that when Kubernetes schedules the Pod to a node, it will ensure that there are enough resources on the node to meet the Pod's requirements.requestOnly when the available resources on the node are greater than or equal to the Pod'srequest, the Pod will be scheduled to the node.
   • requestThere is no upper limit on the resources used by the container. If business needs increase during the operation of the container, more thanrequestof resources, but can only use up tolimitThe amount of resource defined.
   • requestEnsuring that the Pod has enough resources to run is the basic guarantee for container runtime.
2. Limit：
   • limitDefines the maximum value of resources that a container can use. If set to 0, it means that there is no limit on resource usage, and the container can use resources without restriction.
   • limitIts role is to prevent a Pod from using resources without limit, causing other Pods to crash or affecting the stability of the entire cluster.
   • When defining a Pod, you must0 <= request <= limitThis meansrequestThe value is always less than or equal tolimitThe value of .

In summary,requestandlimitThe main difference is that request is the resource guarantee when the container is started, while limit is the upper limit of resource usage when the container is running. By setting these two values ​​reasonably, you can achieve flexible configuration and effective management of container resources and ensure the stability and efficiency of the cluster.

apiVersion: v1  
kind: Pod  
metadata:  
  name: guaranteed-pod  
spec:  
  containers:  
  - name: guaranteed-container  
    image: nginx  
    resources:  
      requests:  
        cpu: 500m  
        memory: 500Mi  
      limits:  
        cpu: 500m  
        memory: 500Mi