** docker使用overlay2无法启动 **
docker配置如下:
```bash
cat /etc/docker/daemon.json
```
```json
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m",
    "max-file": "3"
  }
}
```
报错提示如下:
```
Mar 04 18:16:16 harbor.scm.360.back kernel: overlayfs: upper fs needs to support d_type.
Mar 04 18:16:16 harbor.scm.360.back dockerd[3726]: failed to start daemon: error initializing graphdriver: overlay2: the backing xfs filesystem is formatted without d_type support, which leads to incorrect behavior. Reformat the filesystem with ftype=1 to enable d_type support. Backing filesystems without d_type support are not supported.
Mar 04 18:16:16 harbor.scm.360.back systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
Mar 04 18:16:16 harbor.scm.360.back systemd[1]: Failed to start Docker Application Container Engine.
-- Subject: Unit docker.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.service has failed.
--
-- The result is failed.
```
使用命令
```
xfs_info /
```
打印的信息中  

** ftype=0 ** 

除非重新格式化硬盘，不然无法使用


** 修改配置文件 **  
```json
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "storage-driver": "devicemapper",
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m",
    "max-file": "3"
  }
}
```