编辑kubernetes的 kube-reserved 和 system-reserved

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已于 2024-07-10 13:59:46 修改

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文章标签： kubernetes 容器云原生

于 2024-02-27 16:19:49 首次发布

本文链接：https://blog.youkuaiyun.com/weixin_59526725/article/details/136324602

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本文介绍了如何在Kubernetes集群中，通过编辑kubelet配置文件，预留CPU、内存和存储资源，以防止节点资源耗尽导致集群性能下降。作者详细描述了如何设置kubelet预留值、驱逐策略等，确保集群的正常运行。

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如果Kubernetes集群部署了大量的应用，负载跑满了每个node节点的CPU和Memory后，可能会导致Kubernetes集群自身的运行出问题。所以编辑 kubelet 的配置，预留集群和系统的资源。这里用 kubeadm 部署的1.28.2 k8s 集群。

编辑 kubelet.service 的配置文件，添加下面配置

vim /usr/lib/systemd/system/kubelet.service

[Unit]
Description=kubelet: The Kubernetes Node Agent
Documentation=https://kubernetes.io/docs/
Wants=network-online.target
After=network-online.target

[Service]
ExecStart=/usr/bin/kubelet
Restart=always
StartLimitInterval=0
RestartSec=10

[Install]
WantedBy=multi-user.target

# /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf
# Note: This dropin only works with kubeadm and kubelet v1.11+
[Service]
Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf"
Environment="KUBELET_CONFIG_ARGS=--config=/var/lib/kubelet/config.yaml"
# This is a file that "kubeadm init" and "kubeadm join" generates at runtime, populating the KUBELET_KUBEADM_ARGS variable dynamically
EnvironmentFile=-/var/lib/kubelet/kubeadm-flags.env
# This is a file that the user can use for overrides of the kubelet args as a last resort. Preferably, the user should use
# the .NodeRegistration.KubeletExtraArgs object in the configuration files instead. KUBELET_EXTRA_ARGS should be sourced from this file.
EnvironmentFile=-/etc/sysconfig/kubelet
ExecStart=
ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS

编辑 kubelet 的配置文件，追加以下内容

cat <<EOF | sudo tee -a /var/lib/kubelet/config.yaml
kubeReserved:  #集群预留
  cpu: "0.5"
  memory: "1Gi"
  ephemeral-storage: "1Gi"
systemReserved:  #系统预留，集群外跑了服务才预留这么多。
  cpu: "74"
  memory: "266Gi"
  ephemeral-storage: "1Gi"
evictionHard:  #剩余资源驱逐的硬性阈值
  memory.available: "250Mi"
  nodefs.available: "10%"
  imagefs.available: "10%"
  nodefs.inodesFree: "5%"
EOF

修改好配置，重启 kubelet

systemctl daemon-reload && systemctl restart kubelet && systemctl status kubelet

查看工作节点的详细信息，

kubectl describe node c01n01|grep -A 13 Capacity

可以看到系统资源总容量-预留资源=可分配资源，资源预留成功