K8S Cpu-Manager-Policy

注:K8S版本1.10
K8S使用過程中發現java程序啟動特別慢的情況,這個原因主要是由于K8S CPU上下文的頻繁切換導致的CPU利用率不高。可以通過K8S的cpu-manager-policy來解決這個問題，配置如下。

在kubelet的啟動參數中加入如下參數:

--feature-gates=CPUManager=true --cpu-manager-policy=static --kube-reserved=cpu=1,memory=0

重啟kubelet

systemctl restart kubelet

發現報錯

Jan 23 10:49:30 sh-saas-k8s1-node-dev-02 systemd: Starting Kubernetes systemd probe.
Jan 23 10:49:30 sh-saas-k8s1-node-dev-02 kubelet: panic: [cpumanager] state file: unable to restore state from disk (policy configured "static" != policy from state file "none")
Jan 23 10:49:30 sh-saas-k8s1-node-dev-02 kubelet: Panicking because we cannot guarantee sane CPU affinity for existing containers.
Jan 23 10:49:30 sh-saas-k8s1-node-dev-02 kubelet: Please drain this node and delete the CPU manager state file "/data/kubernetes/kubelet/cpu_manager_state" before restarting Kubelet.
Jan 23 10:49:30 sh-saas-k8s1-node-dev-02 kubelet: goroutine 1 [running]:

這個是由于kubelet有個state文件，按照上面的找到那個文件，手動把狀態改成static即可

重新啟動kubelet，將需要高性能的應用的limit和request設置成一樣，且cpu個數必須為整數個數，這樣K8S會將應用自動進行cpu綁定，性能會有一個比較大的提升。