kubelet服务启动失败，错误代码255

⽤kubeadm的⽅法安装kubelet后，运⾏systemctl status kubelet 发现kubelet服务启动失败，错误代码255。kubelet.service: main process exited, code=exited, status=255/n/a

检查了Swap已经关闭，SELinux已经被disabled，firewalld也已经被disabled，cgroup也已经和docker设置成⼀样。并且发现有时候运⾏systemctl status kubelet 发现kubelet服务是正常的，⼀会再看⼜失败了的灵异事件。后来查了资料，运⾏journalctl -xefu kubelet 命令查看systemd⽇志才发现，真正的错误是：

unable to load client CA file /etc/kubernetes/pki/ca.crt: open /etc/kubernetes/pki/ca.crt: no such file or directory这个错误在运⾏kubeadm init ⽣成CA证书后会被⾃动解决，此处可先忽略。再回过头来看Kubernets官⽅⽂档，其实⾥⾯已经写了很清楚了：

The kubelet is now restarting every few seconds, as it waits in a crashloop for kubeadm to tell it what to do. This crashloop is expected andnormal, please proceed with the next step and the kubelet will start running normally.简单地说就是在kubeadm init 之前kubelet会不断重启。