异常【kubelet cgroup driver：cgroupfs跟docker cgroup driver：systemd不一致】

• 异常描述

  error: failed to run Kubelet: failed to create kubelet: misconfiguration: kubelet cgroup driver: "cgroupfs" is different from docker cgroup driver: "systemd"

  启动kubelet时

  #启动kubelet
  service kubelet start
  #查看kubelet日志
  journalctl -f -u kubelet
  

  提示如下错误

  10月 11 20:05:18 server03 kubelet[15984]: error: failed to run Kubelet: failed to create kubelet: misconfiguration: kubelet cgroup driver: "cgroupfs" is different from docker cgroup driver: "systemd"
  10月 11 20:05:18 server03 systemd[1]: kubelet.service: main process exited, code=exited, status=1/FAILURE
  10月 11 20:05:18 server03 systemd[1]: Unit kubelet.service entered failed state.
  10月 11 20:05:18 server03 systemd[1]: kubelet.service failed.
  
  

• 原因分析
  kubelet文件驱动默认cgroupfs, 而我们安装的docker使用的文件驱动是systemd, 造成不一致, 导致镜像无法启动。
  现在有两种方式, 一种是修改docker, 另一种是修改kubelet。
  我这里采用修改docker的方式
  ==注意==：
  网上大部分教程都是说直接修改daemon.json

  #修改daemon.json
  vi /etc/docker/daemon.json
  #添加如下属性
  "exec-opts": [
      "native.cgroupdriver=systemd"
  ]
  

  这样会导致修改后，docker无法启动成功，提示daemon.json与/lib/systemd/system/docker.service中native.cgroupdriver=systemd重复存在。

• 解决方案（修改docker）

  # 修改前查看docker Cgroup Driver
  [root@server02 ~]# docker info
  ...
  Server Version: 1.13.1
  Storage Driver: overlay2
   Backing Filesystem: xfs
   Supports d_type: true
   Native Overlay Diff: true
  Logging Driver: journald
  Cgroup Driver: systemd
  ...
  

  # 修改docker.service
  vi /lib/systemd/system/docker.service
  

  找到
  --exec-opt native.cgroupdriver=systemd \
  修改为：
  --exec-opt native.cgroupdriver=cgroupfs \
  

  # 重启docker
  systemctl daemon-reload
  systemctl restart docker
  

  # 修改后查看docker Cgroup Driver
  [root@server03 sysconfig]# docker info
  ...
  Server Version: 1.13.1
  Storage Driver: overlay2
   Backing Filesystem: xfs
   Supports d_type: true
   Native Overlay Diff: true
  Logging Driver: journald
  Cgroup Driver: cgroupfs
  ...
  

  参考链接：http://www.cnblogs.com/hongdada/p/9771857.html

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

• 异常描述

  failed to get container info for "/system.slice/kubelet.service": unknown container "/system.slice/kubelet.service"

  启动kubelet时

  service kubelet start
  #查看kubelet日志
  journalctl -f -u kubelet
  

  提示如下错误

  10月 11 19:37:46 server01 kubelet[64872]: E1011 19:37:46.150198   64872 summary.go:92] Failed to get system container stats for "/system.slice/kubelet.service": failed to get cgroup stats for "/system.slice/kubelet.service": failed to get container info for "/system.slice/kubelet.service": unknown container "/system.slice/kubelet.service"
  
  

• 解决方案

  # 修改kubelet.service
  vi /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
  

  修改后的/lib/systemd/system/kubelet.service

  [Unit]
  Description=Kubernetes Kubelet
  Documentation=https://github.com/GoogleCloudPlatform/kubernetes
  After=docker.service
  Requires=docker.service
  
  [Service]
  WorkingDirectory=/var/lib/kubelet
  ExecStart=/opt/modules/kubernetes-bins/kubelet \
    --address=192.168.1.188 \
    --hostname-override=192.168.1.188 \
    --pod-infra-container-image=registry.cn-hangzhou.aliyuncs.com/imooc/pause-amd64:3.0 \
    --kubeconfig=/etc/kubernetes/kubelet.kubeconfig \
    --network-plugin=cni \
    --cni-conf-dir=/etc/cni/net.d \
    --cni-bin-dir=/opt/modules/kubernetes-bins \
    --cluster-dns=10.68.0.2 \
    --cluster-domain=cluster.local. \
    --allow-privileged=true \
    --fail-swap-on=false \
    --logtostderr=true \
    --v=2 \
    --runtime-cgroups=/systemd/system.slice \
    --kubelet-cgroups=/systemd/system.slice
  #kubelet cAdvisor 默认在所有接口监听 4194 端口的请求, 以下iptables限制内网访问
  ExecStartPost=/sbin/iptables -A INPUT -s 10.0.0.0/8 -p tcp --dport 4194 -j ACCEPT
  ExecStartPost=/sbin/iptables -A INPUT -s 172.16.0.0/12 -p tcp --dport 4194 -j ACCEPT
  ExecStartPost=/sbin/iptables -A INPUT -s 192.168.0.0/16 -p tcp --dport 4194 -j ACCEPT
  ExecStartPost=/sbin/iptables -A INPUT -p tcp --dport 4194 -j DROP
  Restart=on-failure
  RestartSec=5
  
  [Install]
  WantedBy=multi-user.target