Kubeadm: サポートされていないグラフドライバリストは不明です

@ggeeは、エラーメッセージ、dockerバージョン情報、kubernetesバージョン情報などを提供してください...

# kubeadm init
[kubeadm] WARNING: kubeadm is in alpha, please do not use it for production clusters.
[preflight] Running pre-flight checks
[preflight] The system verification failed. Printing the output from the verification:
OS: Linux
KERNEL_VERSION: 4.9.0-0.bpo.1-amd64
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 (as module)
CONFIG_PROC_FS: enabled
CONFIG_NETFILTER_XT_TARGET_REDIRECT: enabled (as module)
CONFIG_NETFILTER_XT_MATCH_COMMENT: enabled (as module)
CONFIG_OVERLAY_FS: enabled (as module)
CONFIG_AUFS_FS: not set - Required for aufs.
CONFIG_BLK_DEV_DM: enabled (as module)
CGROUPS_CPU: enabled
CGROUPS_CPUACCT: enabled
CGROUPS_CPUSET: enabled
CGROUPS_DEVICES: enabled
CGROUPS_FREEZER: enabled
CGROUPS_MEMORY: enabled
DOCKER_VERSION: 1.13.1
DOCKER_GRAPH_DRIVER: overlay2
[preflight] Some fatal errors occurred:
    unsupported graph driver: overlay2
[preflight] If you know what you are doing, you can skip pre-flight checks with `--skip-preflight-checks`

# kubeadm version
kubeadm version: version.Info{Major:"1", Minor:"6+", GitVersion:"v1.6.0-alpha.0.2074+a092d8e0f95f52", GitCommit:"a092d8e0f95f5200f7ae2cba45c75ab42da36537", GitTreeState:"clean", BuildDate:"2016-12-13T17:03:18Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}

私にとっても同じですが、1.6.1、Ubuntu 16.04.2 x64の場合：

[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[preflight] Running pre-flight checks
[preflight] The system verification failed. Printing the output from the verification:
OS: Linux
KERNEL_VERSION: 4.4.0-62-generic
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 (as module)
CONFIG_NETFILTER_XT_MATCH_COMMENT: enabled (as module)
CONFIG_OVERLAY_FS: enabled (as module)
CONFIG_AUFS_FS: enabled (as module)
CONFIG_BLK_DEV_DM: enabled
CGROUPS_CPU: enabled
CGROUPS_CPUACCT: enabled
CGROUPS_CPUSET: enabled
CGROUPS_DEVICES: enabled
CGROUPS_FREEZER: enabled
CGROUPS_MEMORY: enabled
DOCKER_VERSION: 1.12.6
DOCKER_GRAPH_DRIVER: btrfs
[preflight] Some fatal errors occurred:
    unsupported graph driver: btrfs
[preflight] If you know what you are doing, you can skip pre-flight checks with `--skip-preflight-checks`

Dockerは確かにbtrfsを使用します：

$ docker version
Client:
 Version:      1.12.6
 API version:  1.24
 Go version:   go1.6.4
 Git commit:   78d1802
 Built:        Tue Jan 10 20:38:45 2017
 OS/Arch:      linux/amd64

Server:
 Version:      1.12.6
 API version:  1.24
 Go version:   go1.6.4
 Git commit:   78d1802
 Built:        Tue Jan 10 20:38:45 2017
 OS/Arch:      linux/amd64
$ cat /etc/docker/daemon.json 
{
  "graph": "/data/docker",
  "storage-driver": "btrfs"
}

--skip-preflight-checks 、ノードはなんとかマスターに参加しました。

これは、ノードチームがoverlay2ドライバーを正式に検証していないためです。これは、警告が表示された状態でそのまま機能します。 私はoverlay2はうまくいくはずだと思います...