build docker deivcemapper

1.创建一个虚拟快设备

dd if=/dev/zero of=4G.img bs=1M count=4096

2.创建loop device

可以先用losetup -f 查看空闲的loop设备

losetup /dev/loop0 /datac/docker/4G.img 

3. 创建PV，VG

pvcreate /dev/loop0

vgcreate docker /dev/loop0

4. 创建thinpool

lvcreate --wipesignatures y -n thinpool docker -l 95%VG

lvcreate --wipesignatures y -n thinpoolmeta docker -l 1%VG

lvconvert -y --zero n -c 512K --thinpool docker/thinpool --poolmetadata docker/thinpoolmeta

5.配置

vi /etc/lvm/profile/docker-thinpool.profile

activation {

    thin_pool_autoextend_threshold=80

    thin_pool_autoextend_percent=20

}
lvchange --metadataprofile docker-thinpool docker/thinpool

6.修改docker配置

/etc/docker/daemon.json

"storage-driver": "devicemapper",
"storage-opts": [
"dm.thinpooldev=/dev/mapper/docker-thinpool",
"dm.use_deferred_removal=true",
"dm.use_deferred_deletion=true"
]

or

--storage-driver=devicemapper --storage-opt=dm.thinpooldev=/dev/mapper/docker-thinpool --storage-opt dm.use_deferred_removal=true

 参考文档

https://docs.docker.com/engine/userguide/storagedriver/device-mapper-driver/