1、Docker之WARNING: IPv4 forwarding is disabled. Networking will not work.

原因：
是没有开启转发,网桥配置完后，需要开启转发，不然容器启动后，就会没有网络，配置/etc/sysctl.conf,添加net.ipv4.ip_forward=1

配置转发

vim /etc/sysctl.conf

#配置转发

net.ipv4.ip_forward=1

#重启服务，让配置生效

systemctl restart network

#查看是否成功,如果返回为"net.ipv4.ip_forward = 1"则表示成功

sysctl net.ipv4.ip_forward

2、k8s删除pod一直处于terminating状态

删除POD

kubectl delete pod [pod name] --force --grace-period=0 -n [namespace]

删除NAMESPACE

kubectl delete namespace NAMESPACENAME --force --gr、ace-period=0

3、Need to upgrade docker package to 17.06.0+. Docker升级到最新版本

rpm -qa | grep docker
yum remove docker-common-1.13.1-208.git7d71120.el7_9.x86_64 docker-common-1.13.1-208.git7d71120.el7_9.x86_64 docker-client-1.13.1-208.git7d71120.el7_9.x86_64
curl -fsSL https://get.docker.com/ | sh
systemctl restart docker && systemctl enable docker

4、【kubeadm初始化报错】failed to run Kubelet: misconfiguration: kubelet cgroup driver: "cgroupfs" is different from docker cgroup driver: "systemd"

cat > /etc/docker/daemon.json <<EOF
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ],
  "data-root": "/data/docker"
}
EOF

检查 docker info|grep "Cgroup Driver" 是否输出 Cgroup Driver: systemd