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Kubernetes----Pod配置资源配额

2022-07-26 14:11:00 【51CTO】

一、Pod资源配额

1.1 资源配额配置简介

容器中的程序要运行，肯定是要占用一定资源的，比如CPU和内存等，如果不对某个容器的资源做限制，那么它就可能吃掉大量资源，导致气他容器无法运行，针对这种情况，kubernetes提供了对内存和CPU的资源进行配额的机制，这种机制主要通过resources选项类实现，它有两个子选项

limits：用于限制运行时容器的最大占用资源，当容器占用资源超过limits时会被终止，并进行重启
requests：用于设置容器需要的最小资源，如果环境资源不够，容器就无法启动

1.2 资源配额配置

如下，编辑pod_base.yaml文件，对nginx容器设置资源上限和下限设置

       
       apiVersion
       
       : v1
       
       kind
       
       : Namespace
       
       metadata
       
       :
       
        name
       
       : dev
       
       ---
       
       apiVersion
       
       : v1
       
       kind
       
       : Pod
       
       metadata
       
       :
       
        name
       
       : pod-resources
       
        namespace
       
       : dev
       
        labels
       
       :
       
        user
       
       : redrose2100
       
       spec
       
       :
       
        containers
       
       :
       
        - 
       
       name
       
       : nginx
       
        image
       
       : nginx
       
       :
       
       1.17.1
       
        resources
       
       :
       
        requests
       
       :
       
        cpu
       
       : 
       
       "1"
       
        memory
       
       : 
       
       "100M"
       
        limits
       
       :
       
        cpu
       
       : 
       
       "2"
       
        memory
       
       : 
       
       "512M"
      
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使用如下命令创建pod

       
       [[email protected] pod]
       
       # kubectl apply -f pod_resources.yaml
       
namespace/dev created
       
pod/pod-resources created
       
[[email protected] pod]
       
       #
      
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使用如下命令查询pod，发现此时的配额配置，环境是满足要求的，pod是能正常启动的

       
       [[email protected] pod]
       
       # kubectl get pod -n dev
       
NAME            READY   STATUS    RESTARTS   AGE
       
pod-resources   
       
       1/1     Running   
       
       0          7s
       
[[email protected] pod]
       
       #
      
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使用如下命令删除资源

       
       [[email protected] pod]
       
       # kubectl delete -f pod_resources.yaml
       
namespace 
       
       "dev" deleted
       
pod 
       
       "pod-resources" deleted
       
[[email protected] pod]
       
       #
      
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1.3 配额超额配置测试

这里可以做个实验，将cpu下限修改为10，上限修改为20，然后再次尝试，因为这里虚拟机的核数是4，下限修改为10后是明显不能满足要求的

       
       apiVersion
       
       : v1
       
       kind
       
       : Namespace
       
       metadata
       
       :
       
        name
       
       : dev
       
       ---
       
       apiVersion
       
       : v1
       
       kind
       
       : Pod
       
       metadata
       
       :
       
        name
       
       : pod-resources
       
        namespace
       
       : dev
       
        labels
       
       :
       
        user
       
       : redrose2100
       
       spec
       
       :
       
        containers
       
       :
       
        - 
       
       name
       
       : nginx
       
        image
       
       : nginx
       
       :
       
       1.17.1
       
        resources
       
       :
       
        requests
       
       :
       
        cpu
       
       : 
       
       "10"
       
        memory
       
       : 
       
       "100M"
       
        limits
       
       :
       
        cpu
       
       : 
       
       "20"
       
        memory
       
       : 
       
       "512M"
      
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然后使用如下命令创建：

       
       [[email protected] pod]
       
       # kubectl apply -f pod_resources.yaml
       
namespace/dev created
       
pod/pod-resources created
       
[[email protected] pod]
       
       #
      
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再次重新创建后通过如下命令可以看到这里提示cpu不够用了

       
       [[email protected] pod]
       
       # kubectl get pod -n dev
       
NAME            READY   STATUS    RESTARTS   AGE
       
pod-resources   
       
       0/1     Pending   
       
       0          17m
       
[[email protected] pod]
       
       # kubectl describe pod pod-resources -n dev
       
Name:         pod-resources
       
Namespace:    dev
       
Priority:     
       
       0
       
Node:         <none>
       
Labels:       
       
       user
       
       =redrose2100
       
Annotations:  <none>
       
Status:       Pending
       
IP:
       
IPs:          <none>
       
Containers:
       
  nginx:
       
    Image:      nginx:1.17.1
       
    Port:       <none>
       
    Host Port:  <none>
       
    Limits:
       
      cpu:     
       
       20
       
      memory:  512M
       
    Requests:
       
      cpu:        
       
       10
       
      memory:     100M
       
    Environment:  <none>
       
    Mounts:
       
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-8kvvb (ro)
       
Conditions:
       
  Type           Status
       
  PodScheduled   False
       
Volumes:
       
  kube-api-access-8kvvb:
       
    Type:                    Projected (a volume that contains injected data from multiple sources)
       
    TokenExpirationSeconds:  
       
       3607
       
    ConfigMapName:           kube-root-ca.crt
       
    ConfigMapOptional:       <nil>
       
    DownwardAPI:             
       
       true
       
QoS Class:                   Burstable
       
Node-Selectors:              <none>
       
Tolerations:                 
       
       node.kubernetes.io/not-ready:NoExecute 
       
       op
       
       =Exists 
       
       for 300s
       
       node.kubernetes.io/unreachable:NoExecute 
       
       op
       
       =Exists 
       
       for 300s
       
Events:
       
  Type     Reason            Age                 From               Message
       
       --
       
       --     
       
       --
       
       --
       
       --            
       
       --
       
       --                
       
       --
       
       --               
       
       --
       
       --
       
       --
       
       -
       
  Warning  FailedScheduling  38s (x19 over 18m)  default-scheduler  
       
       0/3 nodes are available: 
       
       1 
       
       node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn
       
       't tolerate, 2 Insufficient cpu.
       
       [[email protected] pod]#
      
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使用如下命令删除资源

       
       [[email protected] pod]
       
       # kubectl delete -f pod_resources.yaml
       
namespace 
       
       "dev" deleted
       
pod 
       
       "pod-resources" deleted
       
[[email protected] pod]
       
       #
      
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