I installed Ubuntu on WSL2 in the environment shown below. When I tried to register this Ubuntu as a worker node for Kubernetes cluster with the procedures shown below, there happened an error. How is it possible to register Ubuntu?

[my environment]

• Windows 10 Pro Insider Preview 1903 build 18922.1000

  • WSL2

• WSL2 Ubuntu

  • Docker 18.09.5-ce
  • kubectl 1.14.3
  • kubeadm 1.14.3
  • kubelet 1.14.3

• Master Node

  • Ubuntu Server 18.04.2
  • Docker 18.09.5-ce
  • kubectl 1.14.3
  • kubeadm 1.14.3
  • kubelet 1.14.3

[my procedures]

1. run Ubuntu on WSL2

2. start Docker Service

   $ sudo service docker start

3. create a token to join the cluster on MasterNode

   $ kubeadm token generate
   $ kubeadm token create [key] --print-join-command

4. execute the following command on Ubuntu

   $ sudo kubeadm join [masterIP]:6443 --token [token] --discovery-token-ca-cert-hash [hash]

[the result]

[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/
[preflight] The system verification failed. Printing the output from the verification:
KERNEL_VERSION: 4.19.43-microsoft-standard
CONFIG_NAMESPACES: enabled
CONFIG_NET_NS: enabled
CONFIG_PID_NS: enabled
CONFIG_IPC_NS: enabled
CONFIG_UTS_NS: enabled
CONFIG_CGROUPS: enabled
CONFIG_CGROUP_CPUACCT: enabled
CONFIG_CGROUP_DEVICE: enabled
CONFIG_CGROUP_FREEZER: enabled
CONFIG_CGROUP_SCHED: enabled
CONFIG_CPUSETS: enabled
CONFIG_MEMCG: enabled
CONFIG_INET: enabled
CONFIG_EXT4_FS: enabled
CONFIG_PROC_FS: enabled
CONFIG_NETFILTER_XT_TARGET_REDIRECT: enabled
CONFIG_NETFILTER_XT_MATCH_COMMENT: not set
CONFIG_OVERLAY_FS: enabled
CONFIG_AUFS_FS: not set - Required for aufs.
CONFIG_BLK_DEV_DM: enabled
DOCKER_VERSION: 18.09.5
DOCKER_GRAPH_DRIVER: overlay2
OS: Linux
CGROUPS_CPU: enabled
CGROUPS_CPUACCT: enabled
CGROUPS_CPUSET: enabled
CGROUPS_DEVICES: enabled
CGROUPS_FREEZER: enabled
CGROUPS_MEMORY: enabled
error execution phase preflight: [preflight] Some fatal errors occurred:
    [ERROR Service-Docker]: docker service is not active, please run 'systemctl start docker.service'
    [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables does not exist
    [ERROR SystemVerification]: unexpected kernel config: CONFIG_NETFILTER_XT_MATCH_COMMENT
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`