O049、准备 LVM Volume Provider
Cinder 真正负责volume 管理的组件是 volume provider 。Cinder 支持多种 volume provider ，LVM 是默认的volume provider。DevStack 安装之后， /etc/cinder/cinder.conf 已经配置好了LVM。
[root@DevStack-Rocky-Controller-31 ~]# cat /etc/cinder/cinder.conf
[DEFAULT]
default_volume_type = lvmdriver-1
enabled_backends = lvmdriver-1
[lvmdriver-1]
image_volume_cache_enabled = True
volume_clear = zero
lvm_type = auto
target_helper = lioadm
volume_group = stack-volumes-lvmdriver-1
volume_driver = cinder.volume.drivers.lvm.LVMVolumeDriver
volume_backend_name = lvmdriver-1
上面的配置定义了名为 lvmdriver-1 的 volume provider，也称作 back-end。其driver 是LVM，LVM的volume group 名为 stack-volumes-lvmdriver-1 。DevStack 部署 rocky版本的OpenStack 已经帮我们都配置好了。
[root@DevStack-Rocky-Compute-12 lvm]# vgdisplay
--- Volume group ---
VG Name stack-volumes-default
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size <24.00 GiB
PE Size 4.00 MiB
Total PE 6143
Alloc PE / Size 0 / 0
Free PE / Size 6143 / <24.00 GiB
VG UUID 5IdgWN-YX3V-rxNR-08SG-OjDw-M9xS-al102A
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size <159.00 GiB
PE Size 4.00 MiB
Total PE 40703
Alloc PE / Size 40702 / 158.99 GiB
Free PE / Size 1 / 4.00 MiB
VG UUID O7gUtM-Ef0y-XsZ0-trOc-fpWX-uYcc-pefodm
--- Volume group ---
VG Name stack-volumes-lvmdriver-1
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size <24.00 GiB
PE Size 4.00 MiB
Total PE 6143
Alloc PE / Size 5849 / <22.85 GiB
Free PE / Size 294 / <1.15 GiB
VG UUID 5RFdup-8ta0-QsOv-t42v-bAOa-oaX9-gLSPla
后面各小节都将以 LVM 为 volume provider 详细介绍 volume的 各种操作。
