Common errors in k8s initialization

[init] Using Kubernetes version: v1.20.5
[preflight] Running pre-flight checks
    1    [WARNING NumCPU]: the number of available CPUs 1 is less than the required 2
    2    [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/
    3    [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.5. Latest validated version: 19.03
    4    [WARNING Hostname]: hostname "k8s" could not be reached
    5    [WARNING Hostname]: hostname "k8s": lookup k8s on 192.168.0.1:53: no such host

Solution:
1. Adjust the number of CPU cores to the current number of cores + 1 (self adaptation)
2. Change the settings to make the container runtime and kubelet use SYSTEMd as CGroup driver https://blog.whsir.com/post-5312.html
3. Re install docker, and the latest verification version of docker is 19.03
4. Configure domain name resolution/etc/hosts
5. Refer to 4