K8S Pod状态为“被驱逐(evicted)”的解决方法

本文主要是介绍K8S Pod状态为“被驱逐(evicted)”的解决方法，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

在Kubernetes中，pod是最小的调度单元。当Pod无法在所分配的节点上正常运行时，它可能会被驱逐(evicted)。这种情况可能是由多种原因引起，比如节点资源不足、Pod超出了所分配的资源限制、镜像拉取失败等。

驱逐原因

• 节点资源不足：节点资源包括CPU、内存、存储空间等。当节点资源不足以满足Pod的资源需求时，调度器会选择其中一个或多个Pod驱逐出节点。
• 超出资源限制：Pod可以指定资源上线，例如CPU和内存的限制。如果Pod使用的资源超过指定的限制，该Pod可能会被驱逐。
• 镜像拉取失败：如果Pod所需的镜像无法拉取或拉取失败，K8S可能会重试一定次数后将其标记为“evicted”状态。

问题复现

（1）查看K8S中Pod的状态，发现部分pod的STATUS显示“evicted”状态:

（2）使用 kubectl describe 命令查看Pod的状态和事件。

kubectl describe pod <pod-name> -n <namespace-name>

kubectl describe pod knowledge-base-5799896986-zl55n -n asrank

[root@node-1 ~]# kubectl describe pod knowledge-base-5799896986-zl55n -n asrank
Name:           knowledge-base-5799896986-zl55n
Namespace:      asrank
Priority:       0
Node:           node-1/
Start Time:     Fri, 29 Mar 2024 11:12:16 +0800
Labels:         app=knowledge-baseistio.io/rev=defaultpod-template-hash=5799896986security.istio.io/tlsMode=istioservice.istio.io/canonical-name=knowledge-baseservice.istio.io/canonical-revision=latest
Annotations:    kubectl.kubernetes.io/default-container: knowledge-basekubectl.kubernetes.io/default-logs-container: knowledge-baseprometheus.io/path: /stats/prometheusprometheus.io/port: 15020prometheus.io/scrape: truesidecar.istio.io/status:{"initContainers":["istio-init"],"containers":["istio-proxy"],"volumes":["istio-envoy","istio-data","istio-podinfo","istiod-ca-cert"],"ima...
Status:         Failed
Reason:         Evicted
Message:        The node was low on resource: memory. Container knowledge-base was using 43775192Ki, which exceeds its request of 5000Mi. 
IP:             
IPs:            <none>
Controlled By:  ReplicaSet/knowledge-base-5799896986
Init Containers:istio-init:Image:      hub.pmlabs.com.cn/sail/istio/proxyv2:1.10.6Port:       <none>Host Port:  <none>Args:istio-iptables-p15001-z15006-u1337-mREDIRECT-i*-x-b*-d15090,15021,15020Limits:cpu:     2memory:  1GiRequests:cpu:        100mmemory:     128MiEnvironment:  <none>Mounts:/var/run/secrets/kubernetes.io/serviceaccount from default-token-cfzc5 (ro)
Containers:knowledge-base:Image:      hub.pmlabs.com.cn/asrank/knowledge-base:1.01.201Port:       9303/TCPHost Port:  0/TCPLimits:cpu:     24memory:  48GiRequests:cpu:     1memory:  5000MiEnvironment:PROFILE:         prodMYSQL_PASSWORD:  <set to the key 'MYSQL_ROOT_PASSWORD' in secret 'mysql-root-password'>  Optional: falseMounts:/data/ from datasets (rw)/etc/localtime from date-config (rw)/log/ from app-log (rw)/var/run/secrets/kubernetes.io/serviceaccount from default-token-cfzc5 (ro)istio-proxy:Image:      hub.pmlabs.com.cn/sail/istio/proxyv2:1.10.6Port:       15090/TCPHost Port:  0/TCPArgs:proxysidecar--domain$(POD_NAMESPACE).svc.cluster.local--serviceClusterknowledge-base.$(POD_NAMESPACE)--proxyLogLevel=warning--proxyComponentLogLevel=misc:error--log_output_level=default:info--concurrency2Limits:cpu:     2memory:  1GiRequests:cpu:      100mmemory:   128MiReadiness:  http-get http://:15021/healthz/ready delay=1s timeout=3s period=2s #success=1 #failure=30Environment:JWT_POLICY:                    first-party-jwtPILOT_CERT_PROVIDER:           istiodCA_ADDR:                       istiod.istio-system.svc:15012POD_NAME:                      knowledge-base-5799896986-zl55n (v1:metadata.name)POD_NAMESPACE:                 asrank (v1:metadata.namespace)INSTANCE_IP:                    (v1:status.podIP)SERVICE_ACCOUNT:                (v1:spec.serviceAccountName)HOST_IP:                        (v1:status.hostIP)CANONICAL_SERVICE:              (v1:metadata.labels['service.istio.io/canonical-name'])CANONICAL_REVISION:             (v1:metadata.labels['service.istio.io/canonical-revision'])PROXY_CONFIG:                  {}ISTIO_META_POD_PORTS:          [{"containerPort":9303,"protocol":"TCP"}]ISTIO_META_APP_CONTAINERS:     knowledge-baseISTIO_META_CLUSTER_ID:         KubernetesISTIO_META_INTERCEPTION_MODE:  REDIRECTISTIO_META_WORKLOAD_NAME:      knowledge-baseISTIO_META_OWNER:              kubernetes://apis/apps/v1/namespaces/asrank/deployments/knowledge-baseISTIO_META_MESH_ID:            cluster.localTRUST_DOMAIN:                  cluster.localMounts:/etc/istio/pod from istio-podinfo (rw)/etc/istio/proxy from istio-envoy (rw)/var/lib/istio/data from istio-data (rw)/var/run/secrets/istio from istiod-ca-cert (rw)/var/run/secrets/kubernetes.io/serviceaccount from default-token-cfzc5 (ro)
Volumes:istio-envoy:Type:       EmptyDir (a temporary directory that shares a pod's lifetime)Medium:     MemorySizeLimit:  <unset>istio-data:Type:       EmptyDir (a temporary directory that shares a pod's lifetime)Medium:     SizeLimit:  <unset>istio-podinfo:Type:  DownwardAPI (a volume populated by information about the pod)Items:metadata.labels -> labelsmetadata.annotations -> annotationslimits.cpu -> cpu-limitrequests.cpu -> cpu-requestistiod-ca-cert:Type:      ConfigMap (a volume populated by a ConfigMap)Name:      istio-ca-root-certOptional:  falsedate-config:Type:          HostPath (bare host directory volume)Path:          /etc/localtimeHostPathType:  datasets:Type:          HostPath (bare host directory volume)Path:          /var/asrank/knowledge-base/dataHostPathType:  app-log:Type:          HostPath (bare host directory volume)Path:          /var/log/app/asrank/knowledge-baseHostPathType:  default-token-cfzc5:Type:        Secret (a volume populated by a Secret)SecretName:  default-token-cfzc5Optional:    false
QoS Class:       Burstable
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 2snode.kubernetes.io/unreachable:NoExecute op=Exists for 2s
Events:Type     Reason   Age   From     Message----     ------   ----  ----     -------Warning  Evicted  59m   kubelet  The node was low on resource: memory. Container knowledge-base was using 43775192Ki, which exceeds its request of 5000Mi.Normal   Killing  59m   kubelet  Stopping container knowledge-baseNormal   Killing  59m   kubelet  Stopping container istio-proxy

在Events事件中可以看到，由于该Pod在运行中所需内存超出deployments中request的内存，导致该Pod的container被killed，Pod变为被驱逐(evicted)状态。

Events:Type     Reason   Age   From     Message----     ------   ----  ----     -------Warning  Evicted  59m   kubelet  The node was low on resource: memory. Container knowledge-base was using 43775192Ki, which exceeds its request of 5000Mi.Normal   Killing  59m   kubelet  Stopping container knowledge-baseNormal   Killing  59m   kubelet  Stopping container istio-proxy

解决方案

1. 分析Pod资源使用情况：检查被驱逐的Pod的资源使用情况，如内存、CPU和磁盘使用率。可以使用kubectl describe pod <pod_name>命令查看Pod的状态和事件。
2. 调整资源限制：根据实际需求调整Pod的资源限制，如增加内存限制或CPU限制。可以在Pod YAML文件中修改资源限制，然后使用kubectl apply -f <pod_yaml_file>命令更新Pod。
3. 扩容节点：如果集群中的所有节点都面临资源不足的情况，可以考虑扩容节点以提供更多资源。可以使用云服务提供商的管理控制台或API扩容节点。
4. 优化应用：优化应用程序以减少资源使用，如减少内存泄漏、优化CPU使用等。
5. 使用优先级和抢占：为Pod设置优先级，以便在资源紧张时根据优先级驱逐Pod。可以在Pod的YAML文件中设置priorityClassName字段。
6. 批量清理

根据上述分析，本次事件是由于资源不足导致的。可以根据实际需求调整Pod的资源限制，在Pod的YAML文件中修改资源限制，然后使用kubectl apply -f <pod_yaml_file>命令更新Pod。

有k9s界面的情况下，也可进行如下操作：
（1）基于k9s，输入 :deployments
（2）选择对应的Pod，按 e 键进入编辑模式
（3）修改 resource 资源信息，使得满足程序运行所需资源大小。如：

	requests:cpu: 10memory: 5Gilimits:cpu: 24memory: 48Gi

（4）清理Pod

确认没问题后再做删除被驱逐(evicted)的Pod。

# 查看被驱逐(evicted)的Pod
kubectl get pods -n <namespace-name> |grep  Evicted

# 执行批量删除
kubectl get pods -n <namespace-name> | grep Evicted | awk '{print $1}' | xargs kubectl delete pod -n <namespace-name>

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