如何把docker的storage driver改成devicemapper

如何把docker的storage driver改成devicemapper

分两步：

第一步：为VM添加一块disk设备

参考如果给VirtualBox添加设备。

第二步：参考docker文档

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

下面命令内容都是从上述文档链接拷贝下来的。

1. Add block device (refer to 第一步)
   For exampe /dev/sdb
2. Stop docker

$ sudo systemctl stop docker

2. Create a physical volume on above block device

$ sudo pvcreate /dev/sdb

3. Create a docker volume group on above block device

$ sudo vgcreate docker /dev/sdb

4. Create two logical volumes named thinpool and thinpoolmeta using the lvcreate command

$ sudo lvcreate --wipesignatures y -n thinpool docker -l 95%VG
$ sudo lvcreate --wipesignatures y -n thinpoolmeta docker -l 1%VG

5. Convert the volumes to a thin pool and a storage location for metadata for the thin pool

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

6. Configure autoextension of thin pools
   Specify thin_pool_autoextend_threshold and thin_pool_autoextend_percent values.

$ sudo vi /etc/lvm/profile/docker-thinpool.profile
activation {
  thin_pool_autoextend_threshold=80
  thin_pool_autoextend_percent=20
}

7. Apply the LVM profile

$ sudo lvchange --metadataprofile docker-thinpool docker/thinpool

8. Enable monitoring for logical volumes on your host.

$ sudo lvs -o+seg_monitor

9. Backup /var/lib/docker

$ mkdir /var/lib/docker.bk
$ mv /var/lib/docker/* /var/lib/docker.bk

10. Edit /etc/docker/daemon.json and configure the options needed for the devicemapper storage driver.

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

11. Start docker

$ sudo systemctl start docker

12. Verify that Docker is using the new configuration

$ docker info

Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 0
Server Version: 17.03.1-ce
Storage Driver: devicemapper
 Pool Name: docker-thinpool
...

13. Remove backup of /var/lib/docker

$ rm -rf /var/lib/docker.bk