K8S版本：1.17.11

今天查看kubelet日志的时候，发信一堆报错：

查看kubelet日志：
]# journalctl -f -u kubelet

]# tail -f /var/log/messages
Dec  2 16:40:41 master kubelet: E1202 16:40:41.294907    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3987 Dec  2 16:40:51 master kubelet: E1202 16:40:51.357545    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3988 Dec  2 16:41:01 master kubelet: E1202 16:41:01.387170    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3989 Dec  2 16:41:11 master kubelet: E1202 16:41:11.413174    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3990 Dec  2 16:41:21 master kubelet: E1202 16:41:21.479766    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3991 Dec  2 16:41:31 master kubelet: E1202 16:41:31.551083    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3992 Dec  2 16:41:41 master kubelet: E1202 16:41:41.595900    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3993 Dec  2 16:41:51 master kubelet: E1202 16:41:51.662374    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3994 Dec  2 16:42:01 master kubelet: E1202 16:42:01.716067    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3995 Dec  2 16:42:11 master kubelet: E1202 16:42:11.773051    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3996 Dec  2 16:42:21 master kubelet: E1202 16:42:21.826902    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3997 Dec  2 16:42:31 master kubelet: E1202 16:42:31.876961    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3998 Dec  2 16:42:41 master kubelet: E1202 16:42:41.932225    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"
 3999 Dec  2 16:42:52 master kubelet: E1202 16:42:52.034354    1010 summary_sys_containers.go:47] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get c      ontainer info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"

网上搜了一堆，大致原因是kubernetes和docker版本兼容性问题，查看docker版本

]# docker info
Client:
 Debug Mode: false

Server:
 Containers: 34
  Running: 26
  Paused: 0
  Stopped: 8
 Images: 77
 Server Version: 19.03.13
 Storage Driver: overlay2
  Backing Filesystem: xfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs

网上方法：

在10-kubeadm.conf文件中"KUBELET_CGROUP_ARGS"属性添加"--runtime-cgroups=/systemd/system.slice --kubelet-cgroups=/systemd/system.slice" ，如果不存在"KUBELET_CGROUP_ARGS"属性则新增。

10-kubeadm.conf的路径网上提到的多为：/etc/systemd/system/kubelet.service.d/10-kubeadm.conf

而我的K8S尝试了之后并不好使（应该是我的版本太低），并且kubelet启动失败

找到一篇文章：https://stackoverflow.com/questions/46726216/kubelet-fails-to-get-cgroup-stats-for-docker-and-kubelet-services

按照以下方法修改后报错消失

]# vim /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS="--runtime-cgroups=/systemd/system.slice --kubelet-cgroups=/systemd/system.slice"

重新加载配置文件

systemctl daemon-reload
systemctl restart kubelet