Configuring DeviceMapper for Docker

For this lesson, use a CentOS 7 server with a size of Small. Before starting the lesson, you’ll first need to install Docker.
Add a new storage device to your server. In Playground, select Actions, then select Add /dev/nvme1n1 and wait for it to finish adding the device.

Stop and disable Docker.

sudo systemctl disable docker
sudo systemctl stop docker

Delete any existing Docker data.
```
sudo rm -rf /var/lib/docker
```

Configure DeviceMapper in daemon.json.

sudo vi /etc/docker/daemon.json

{
  "storage-driver": "devicemapper",
  "storage-opts": [
    "dm.directlvm_device=/dev/nvme1n1",
    "dm.thinp_percent=95",
    "dm.thinp_metapercent=1",
    "dm.thinp_autoextend_threshold=80",
    "dm.thinp_autoextend_percent=20",
    "dm.directlvm_device_force=true"
  ]
}

Start and enable Docker.

sudo systemctl enable docker
sudo systemctl start docker

Check the storage driver information provided by docker info.
```
docker info
```
Run a container to verify that everything is working.
```
docker run hello-world
```

Configuring DeviceMapper for Docker

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