CentOS 7配置Docker Storage

野崎君noZakiKu 2018-05-20

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背景

CentOS 7已經(jīng)集成了Docker Engine, 并且提供了docker-storage-setup服務(wù)來幫助配置docker服務(wù)的devicemapper存儲驅(qū)動，如果該驅(qū)動自動配置失敗，則docker服務(wù)的存儲驅(qū)動會降級為lvm-loop驅(qū)動。由于loop設(shè)備的緩存問題，lvm-loop模式不適合生產(chǎn)環(huán)境。

CentOS 7的安裝程序默認(rèn)使用lvm模式管理磁盤，如果僅有一塊磁盤，安裝程序會在該物理卷(pv)上創(chuàng)建centos卷組(vg), 并同時使用所有空間創(chuàng)建home和root邏輯卷(lv)。

服務(wù)docker-storage-setup默認(rèn)會嘗試使用root文件系統(tǒng)所屬的vg, 即centos vg，但是由于該vg上已經(jīng)沒有剩余空間，從而導(dǎo)致devicemapper驅(qū)動配置失敗。

減小home lvm的大小創(chuàng)建docker lvm

CentOS 7默認(rèn)安裝程序創(chuàng)建的home lv空間一般比較大，先減小其大小:

lvresize -L -50G /dev/centos/home

重新創(chuàng)建并掛載home文件系統(tǒng)

umount /home
mkfs.xfs /dev/centos/home
mount /home

使用docker-storage-setup配置devicemapper驅(qū)動, 執(zhí)行:

servicedockerstop
rm -rf /var/lib/docker
servicedockerstart

添加新的存儲設(shè)備創(chuàng)建docker lvm

停止docker服務(wù)，并清除已有的docker storage:

servicedockerstop
rm -rf /var/lib/docker

編輯/etc/sysconfig/docker-storage-setup:

DEVS=/dev/sdb
VG=docker

配置devicemapper驅(qū)動：

[root@localhost ~]# docker-storage-setup
INFO: Volumegroupbackingrootfilesystemcouldnot bedetermined
INFO: Device /dev/sdbis alreadypartitionedand is partofvolumegroupdocker
  Roundingupsizeto fullphysicalextent 12.00 MiB
  Logicalvolume "docker-poolmeta" created.
  Logicalvolume "docker-pool" created.
  WARNING: Convertinglogicalvolumedocker/docker-pooland docker/docker-poolmetato pool's dataand metadatavolumes.
  THIS WILLDESTROYCONTENTOFLOGICALVOLUME (filesystemetc.)
  Converteddocker/docker-poolto thinpool.
  Logicalvolume "docker-pool" changed.

重啟docker服務(wù):

servicedockerstart

確認(rèn)配置生效: a) vg信息:

[root@localhost ~]# vgdisplay
  --- Volumegroup ---
  VGName              docker
  SystemID
  Format                lvm2
  MetadataAreas        1
  MetadataSequenceNo  6
  VGAccess            read/write
  VGStatus            resizable
  MAXLV                0
  CurLV                1
  OpenLV              0
  MaxPV                0
  CurPV                1
  ActPV                1
  VGSize              10.00 GiB
  PESize              4.00 MiB
  TotalPE              2559
  AllocPE / Size      1028 / 4.02 GiB
  Free  PE / Size      1531 / 5.98 GiB
  VGUUID              v1eiA1-P7CS-pUx9-D0uS-eVwZ-41pA-SKdlef

b) docker info:

[root@localhost ~]# docker info
Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 0
ServerVersion: 1.10.3
StorageDriver: devicemapper
 PoolName: docker-docker--pool
 PoolBlocksize: 524.3 kB
 BaseDeviceSize: 10.74 GB
 BackingFilesystem: xfs
 Datafile:
 Metadatafile:
 DataSpaceUsed: 20.45 MB
 DataSpaceTotal: 4.287 GB
 DataSpaceAvailable: 4.266 GB
 MetadataSpaceUsed: 40.96 kB
 MetadataSpaceTotal: 12.58 MB
 MetadataSpaceAvailable: 12.54 MB
 UdevSyncSupported: true
 DeferredRemovalEnabled: true
 DeferredDeletionEnabled: true
 DeferredDeletedDeviceCount: 0
 LibraryVersion: 1.02.107-RHEL7 (2016-06-09)
ExecutionDriver: native-0.2
LoggingDriver: json-file
Plugins:
 Volume: local
 Network: bridgenull host
KernelVersion: 3.10.0-327.22.2.el7.x86_64
OperatingSystem: CentOSLinux 7 (Core)
OSType: linux
Architecture: x86_64
NumberofDockerHooks: 2
CPUs: 2
TotalMemory: 1.782 GiB
Name: localhost.localdomain
ID: AY7O:H2RJ:33J5:62FY:GHZE:AGFH:F42E:AH3J:WY7N:JXQK:LHBS:BDKY
WARNING: bridge-nf-call-iptablesis disabled
WARNING: bridge-nf-call-ip6tablesis disabled
Registries: docker.io (secure)

3) Docker Storage配置選項，查看/etc/sysconfig/docker-storage:

DOCKER_STORAGE_OPTIONS="--storage-driver devicemapper --storage-opt dm.fs=xfs --storage-opt dm.thinpooldev=/dev/mapper/centos-docker--pool --storage-opt dm.use_deferred_removal=true --storage-opt dm.use_deferred_deletion=true "

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