k8s资源之PodDisruptionBudget

朱雀 2023-06-27 15:59 43阅读 0赞

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![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAaHhwamF2YTE_size_8_color_FFFFFF_t_70_g_se_x_16][]

目前刚开始写一个月，一共写了18篇原创文章，文章目录如下：

[istio多集群探秘，部署了50次多集群后我得出的结论][istio_50]

[istio多集群链路追踪，附实操视频][istio]

[istio防故障利器，你知道几个,istio新手不要读，太难！][istio_istio]

[istio业务权限控制，原来可以这么玩][istio 1]

[istio实现非侵入压缩，微服务之间如何实现压缩][istio 2]

[不懂envoyfilter也敢说精通istio系列-http-rbac-不要只会用AuthorizationPolicy配置权限][envoyfilter_istio_-http-rbac-_AuthorizationPolicy]

[不懂envoyfilter也敢说精通istio系列-02-http-corsFilter-不要只会vs][envoyfilter_istio_-02-http-corsFilter-_vs]

[不懂envoyfilter也敢说精通istio系列-03-http-csrf filter-再也不用再代码里写csrf逻辑了][envoyfilter_istio_-03-http-csrf filter-_csrf]

[不懂envoyfilter也敢说精通istio系列http-jwt\_authn-不要只会RequestAuthorization][envoyfilter_istio_http-jwt_authn-_RequestAuthorization]

[不懂envoyfilter也敢说精通istio系列-05-fault-filter-故障注入不止是vs][envoyfilter_istio_-05-fault-filter-_vs]

[不懂envoyfilter也敢说精通istio系列-06-http-match-配置路由不只是vs][envoyfilter_istio_-06-http-match-_vs]

[不懂envoyfilter也敢说精通istio系列-07-负载均衡配置不止是dr][envoyfilter_istio_-07-_dr]

[不懂envoyfilter也敢说精通istio系列-08-连接池和断路器][envoyfilter_istio_-08-]

[不懂envoyfilter也敢说精通istio系列-09-http-route filter][envoyfilter_istio_-09-http-route filter]

[不懂envoyfilter也敢说精通istio系列-network filter-redis proxy][envoyfilter_istio_-network filter-redis proxy]

[不懂envoyfilter也敢说精通istio系列-network filter-HttpConnectionManager][envoyfilter_istio_-network filter-HttpConnectionManager]

[不懂envoyfilter也敢说精通istio系列-ratelimit-istio ratelimit完全手册][envoyfilter_istio_-ratelimit-istio ratelimit]

————————————————

# PodDisruptionBudget： #

•pod 中断 预算、

•终止pod前 通过labelSelector机制获取正常运行的pod数目的限制，目的是对主动驱逐的保护措施。

**特性：**

•PDB指定一个pod集合在一段时间内存活的最小实例数量或者百分比

•作用于一组被同一个控制器管理的pod。例如：RS或者statefulset

•使用PodDisruptionBudget控制器本身无法真正保障指定数量或者百分比的pod存活，PodDisruptionBudget控制器只能保证POD主动逃离的情况下业务不中断或者业务SLA不

•降级场景局限于：主动驱逐

•一个 PDB 对应一个控制器创建的 Pod，例如，Deployment、ReplicaSet或StatefulSet。

maxUnavailable 为 0%（或0）或者 minAvailable 为 100%（或与控制器的 .spec.replicas 相等）将阻止节点排空任务

# 舍入： #

•如果指定这些值为一个百分数，其计算结果可能不会正好是一个整数。例如，假设有 7 个 Pod，minAvailable 设置为 50%，你将很难判断，到底是 3 个还是 4 个 Pod 必须始终保持可用。Kubernetes 将向上舍入（round up to the nearest integer），因此，此处必须有 4 个 Pod 始终可用。

# 示例： #

apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: nginx-deployment
      labels:
        app: nginx
    spec:
      selector:
        matchLabels:
          app: nginx
      replicas: 8
      template:
        metadata:
          labels:
            app: nginx
        spec:
          containers:
          - name: nginx
            image: nginx
            ports:
            - containerPort: 80
    
    [root@master01 pdb]# cat pdb-avaliable.yaml 
    apiVersion: policy/v1beta1  
    kind: PodDisruptionBudget  
    metadata:  
     name: nginx-pdb  
    spec:  
     minAvailable: 7  
     selector:  
       matchLabels:  
         app: nginx
    
    
    [root@master01 pdb]# cat pdb-avaliable-noevit.yaml 
    apiVersion: policy/v1beta1  
    kind: PodDisruptionBudget  
    metadata:  
     name: nginx-pdb  
    spec:  
     minAvailable: 100%  
     selector:  
       matchLabels:  
         app: nginx
    
    [root@master01 pdb]# cat pdb-unavaliable.yaml 
    apiVersion: policy/v1beta1  
    kind: PodDisruptionBudget  
    metadata:  
     name: nginx-pdb  
    spec:  
     maxUnavailable: 1  
     selector:  
       matchLabels:  
         app: nginx
    
    [root@master01 pdb]# cat pdb-unavaliable-noevit.yaml 
    apiVersion: policy/v1beta1  
    kind: PodDisruptionBudget  
    metadata:  
     name: nginx-pdb  
    spec:  
     maxUnavailable: 0% 
     selector:  
       matchLabels:  
         app: nginx

命令：

•Kubectl cordon

•Kubectl uncordon

•kubectl drain

•kubectl drain foo –force

•kubectl drain foo --grace-period=900

•Kubectl drain 192.168.198.156 --ignore-daemonsets \--delete-local-data

•kubectl create pdb my-pdb \--selector=app=nginx \--min-available=50%

•kubectl create poddisruptionbudget my-pdb \--selector=app=rails --min-available=1

•Kubectl create pdb my-pdb –selector=app=nginx \--max-unavailable=50%

•Kubectl create pdb my-pdb –selector=app=nginx \--max-unavailable=1

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAaHhwamF2YTE_size_8_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/20211007094240106.jpg?x-oss-process=image/watermark,type_ZHJvaWRzYW5zZmFsbGJhY2s,shadow_50,text_Q1NETiBAaHhwamF2YTE=,size_8,color_FFFFFF,t_70,g_se,x_16
[istio_50]: https://mp.weixin.qq.com/s/_OPMjmWCDSTlmbAxytg33A
[istio]: https://mp.weixin.qq.com/s/kjvtno_UzJAGr1joxm3tvw
[istio_istio]: https://mp.weixin.qq.com/s/e2-p_NY31Mc5y07S4Bb1JQ
[istio 1]: https://mp.weixin.qq.com/s/iTV0SCQLhSOTYncp3PxoHQ
[istio 2]: https://mp.weixin.qq.com/s/eINlrT242RlAwfuZu1_PcA
[envoyfilter_istio_-http-rbac-_AuthorizationPolicy]: https://mp.weixin.qq.com/s/Q-yTGBNqkjOov49LTXPrPA
[envoyfilter_istio_-02-http-corsFilter-_vs]: https://mp.weixin.qq.com/s/bFMdrT7OKSqoWv8pDXOIqQ
[envoyfilter_istio_-03-http-csrf filter-_csrf]: https://mp.weixin.qq.com/s/dlG9phV-kMMxs4UPzuRNYg
[envoyfilter_istio_http-jwt_authn-_RequestAuthorization]: https://mp.weixin.qq.com/s/IfrJ-FdLYsdhPkDrcO_YXA
[envoyfilter_istio_-05-fault-filter-_vs]: https://mp.weixin.qq.com/s/a4gDXqD8uswgglMwkUph2Q
[envoyfilter_istio_-06-http-match-_vs]: https://mp.weixin.qq.com/s/TpS3DHdcaJiPivIS_jsIGw
[envoyfilter_istio_-07-_dr]: https://mp.weixin.qq.com/s/k-zJm7n7OOKg6MotQJYPAA
[envoyfilter_istio_-08-]: https://mp.weixin.qq.com/s/n_bJ3saNeTtXRprIymhwzg
[envoyfilter_istio_-09-http-route filter]: https://mp.weixin.qq.com/s/JAeZr0BMVQxIrB3S_7Ru0A
[envoyfilter_istio_-network filter-redis proxy]: https://mp.weixin.qq.com/s/B9IPTI8F3q42nVkqbQRlPw
[envoyfilter_istio_-network filter-HttpConnectionManager]: https://mp.weixin.qq.com/s/W3OPQWkCVvuHGS49cTNhlg
[envoyfilter_istio_-ratelimit-istio ratelimit]: https://mp.weixin.qq.com/s/KgiDsELNol27mgZvDbFsqw