Docker configuration with direct-lvm in a machine with single disk

Hi I want install docker with direct-lvm
in manual they write :
{
“storage-driver”: “devicemapper”,
“storage-opts”: [
“dm.directlvm_device=/dev/xdf”,
“dm.thinp_percent=95”,
“dm.thinp_metapercent=1”,
“dm.thinp_autoextend_threshold=80”,
“dm.thinp_autoextend_percent=20”,
“dm.directlvm_device_force=false”
]
}

In my machine i have disk /dev/sda with 2 partitions

Device Free Used Total Pool Mount point

/dev/sda 1.17 TB PARTITIONED
/dev/sda1 200.00 MB /boot
/dev/sda2 0.00 KB 1.17 TB 1.17 TB vg

LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
root vg -wi-ao---- 1,17t

The parttion /dev/sda2 it is installed also my OS. How to install? Can i use /dev/sda2 for creatinng a second VG docker inside the same partition and LV thinpool and thinpoolmeta or i have forcely to create another physical partition?