[WARNING IsDockerSystemdCheck]: detected “cgroupfs“ as the Docker cgroup driver

kubeadm init时出现

[init] Using Kubernetes version: v1.20.9
[preflight] Running pre-flight checks
	[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
	[WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.7. Latest validated version: 19.03
	[WARNING Hostname]: hostname "docker-master" could not be reached
	[WARNING Hostname]: hostname "docker-master": lookup docker-master on 183.60.83.19:53: no such host
error execution phase preflight: [preflight] Some fatal errors occurred:
	[ERROR FileContent--proc-sys-net-ipv4-ip_forward]: /proc/sys/net/ipv4/ip_forward contents are not set to 1
[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

cat > /etc/docker/daemon.json < 
systemctl restart docker
systemctl status docker