kubernetes(kubeadm)集群的安装问题总结

1、kubelet与docker驱动不一致(网上其他解决文案各种尝试无效，最后使用如下方法解决)
异常【kubelet cgroup driver：cgroupfs跟docker cgroup driver：systemd不一致】

异常描述如下：
failed to create kubelet: misconfiguration: kubelet cgroup driver: "cgroupfs" is different from docker cgroup driver: "systemd"

• 原因分析
  kubelet文件驱动默认cgroupfs, 而安装的docker使用的文件驱动是systemd, 造成不一致, 导致镜像无法启动。
• 解决方法：
  1）确认docker配置文件daemon.json的驱动配置

  [root@master~]# cat  /etc/docker/daemon.json
  {
  "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"]
  }

  2）修改/var/lib/kubelet/kubeadm-flags.env驱动配置，添加--cgroup-driver=systemd 参数

  [root@master~]# cat /var/lib/kubelet/kubeadm-flags.env
  KUBELET_KUBEADM_ARGS="--cgroup-driver=systemd --network-plugin=cni --pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.1"
  #重启docker与kubelet
  [root@master~]# systemctl daemon-reload && systemctl restart docker kubelet

  
  2、/system.slice/kubelet.service无法识别

• 异常【Failed to get system container stats for kubelet.service】

  异常描述如下
  failed to get container info for "/system.slice/kubelet.service": unknown container "/system.slice/kubelet.service"

• 解决方案

  修改kubelet.service
  [root@master~]# vim /lib/systemd/system/kubelet.service
  #在ExecStart位置最后面，添加如下配置
  --runtime-cgroups=/systemd/system.slice \
  --kubelet-cgroups=/systemd/system.slice

3、kubeadm初始化时报[ERROR NumCPU]

• 异常描述如下

  kubeadm init --apiserver-advertise-address=10.10.10.129 --image-repository registry.aliyuncs.com/google_contain
  ers --kubernetes-version v1.17.0 --service-cidr=10.96.0.0/12 --pod-network-cidr=10.244.0.0/16W0521 22:45:14.131024    8293 validation.go:28] Cannot validate kube-proxy config - no validator is available
  W0521 22:45:14.131095    8293 validation.go:28] Cannot validate kubelet config - no validator is available
  [init] Using Kubernetes version: v1.17.0
  [preflight] Running pre-flight checks
  error execution phase preflight: [preflight] Some fatal errors occurred:
  [ERROR NumCPU]: the number of available CPUs 1 is less than the required 2
  [preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
  To see the stack trace of this error execute with --v=5 or higher

• 解决方案1：
  这种错误一般会出现在VMware虚拟机上，因为新建VM时默认为一核，可通过配置，调整成2核，重启系统即可，如下所示：
  
• 解决方案2：
  根据提示添加忽略错误提示--ignore-preflight-errors=...

  $ kubeadm init \
  --apiserver-advertise-address=10.10.10.129 \
  --image-repository registry.aliyuncs.com/google_containers \
  --kubernetes-version v1.17.0 \
  --service-cidr=10.96.0.0/12 \
  --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=NumCPU