ISCSI：后端卷以LVM 的方式配置 ISCSI 目标启动器

写在前面

准备考试整理相关笔记
博文内容涉及使用 LVM 做ISCSI 目标后端块存储 Demo
理解不足小伙伴帮忙指正

对每个人而言，真正的职责只有一个：找到自我。然后在心中坚守其一生，全心全意，永不停息。所有其它的路都是不完整的，是人的逃避方式，是对大众理想的懦弱回归，是随波逐流，是对内心的恐惧 ——赫尔曼·黑塞《德米安》

目标端配置

配置 servera 提供一个 iSCSI 服务，磁盘名为 iqn.2014-11.com.example:servera ，并符合下列
要求：

服务端口为 3260
使用 iscsi_store 作其后端卷其大小为 3G
此服务只能被 serverb.lab.example.com 访问
后端卷为 LVM 形式

LVM 准备

查看磁盘情况

NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda    252:0    0  20G  0 disk
└─vda1 252:1    0  10G  0 part /
vdb    252:16   0   5G  0 disk

给 vda 做一个分区

[root@servera iscsi-review]# fdisk /dev/vdaWelcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.Command (m for help): n
Partition typep   primary (1 primary, 0 extended, 3 free)e   extended (container for logical partitions)
Select (default p): p
Partition number (2-4, default 2):
First sector (20971487-41943039, default 20971520):
Last sector, +sectors or +size{K,M,G,T,P} (20971520-41943039, default 41943039):Created a new partition 2 of type 'Linux' and of size 10 GiB.Command (m for help): w
The partition table has been altered.
Syncing disks.[root@servera iscsi-review]# lsblk
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda    252:0    0  20G  0 disk
├─vda1 252:1    0  10G  0 part /
└─vda2 252:2    0  10G  0 part
vdb    252:16   0   5G  0 disk

创建物理卷，卷组，逻辑卷

在卷组 myvg 中创建一个名为 myvg 的逻辑卷（Logical Volume），大小为 3GB

[root@servera iscsi-review]# pvcreate /dev/vd
vda   vda1  vda2  vdb
[root@servera iscsi-review]# pvcreate /dev/vda2Physical volume "/dev/vda2" successfully created.
[root@servera iscsi-review]# vgcreate  myvg /dev/vda2Volume group "myvg" successfully created
[root@servera iscsi-review]# lvcreate -n myvg -L 3G myvgLogical volume "myvg" created.

ISCSI 相关配置

安装 targetcli 软件包并启用 target 服务。

[root@servera iscsi-review]# yum -y install  targetcli >> /dev/null
[root@servera iscsi-review]# systemctl enable  --now target.service
Created symlink /etc/systemd/system/multi-user.target.wants/target.service → /usr/lib/systemd/system/target.service.
[root@servera iscsi-review]#

使用 targetcli 工具进入交互式命令行界面。
创建了一个块存储对象 iscsi_store，并将 /dev/myvg/myvg 分配给它。
创建了一个名为 iqn.2014-11.com.example:servera 的 iSCSI 目标。
在 iqn.2014-11.com.example:servera 目标的 TPG1 下创建了一个 LUN，并将 iscsi_store 块存储对+ 象映射到该 LUN。
创建了一个 ACL，允许名为 iqn.2014-11.com.example:serverb 的 iSCSI Initiator 访问上述目标。
删除了一个名为 0.0.0.0:3260 的网络端口。
创建了一个新的网络端口 172.25.250.10:3260。

[root@servera ~]# targetcli
Warning: Could not load preferences file /root/.targetcli/prefs.bin.
targetcli shell version 2.1.fb49
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'./> /backstores/block create  iscsi_store /dev/myvg/myvg
Created block storage object iscsi_store using /dev/myvg/myvg.
/> /iscsi create iqn.2014-11.com.example:servera
Created target iqn.2014-11.com.example:servera.
Created TPG 1.
Global pref auto_add_default_portal=true
Created default portal listening on all IPs (0.0.0.0), port 3260.
/> /iscsi/iqn.2014-11.com.example:servera/tpg1/luns create  /backstores/block/iscsi_store
Created LUN 0.
/> /iscsi/iqn.2014-11.com.example:servera/tpg1/acls create iqn.2014-11.com.example:serverb
Created Node ACL for iqn.2014-11.com.example:serverb
Created mapped LUN 0.
/> /iscsi/iqn.2014-11.com.example:servera/tpg1/portals delete 0.0.0.0 3260
Deleted network portal 0.0.0.0:3260
/> /iscsi/iqn.2014-11.com.example:servera/tpg1/portals create  172.25.250.10 3260
Using default IP port 3260
Created network portal 172.25.250.10:3260.

查看配置情况

/> ls /
o- / ............................................................................................ [...]o- backstores ................................................................................. [...]| o- block ..................................................................... [Storage Objects: 1]| | o- iscsi_store ................................... [/dev/myvg/myvg (3.0GiB) write-thru activated]| |   o- alua ...................................................................... [ALUA Groups: 1]| |     o- default_tg_pt_gp .......................................... [ALUA state: Active/optimized]| o- fileio .................................................................... [Storage Objects: 0]| o- pscsi ..................................................................... [Storage Objects: 0]| o- ramdisk ................................................................... [Storage Objects: 0]o- iscsi ............................................................................... [Targets: 1]| o- iqn.2014-11.com.example:servera ...................................................... [TPGs: 1]|   o- tpg1 .................................................................. [no-gen-acls, no-auth]|     o- acls ............................................................................. [ACLs: 1]|     | o- iqn.2014-11.com.example:serverb ......................................... [Mapped LUNs: 1]|     |   o- mapped_lun0 .............................................. [lun0 block/iscsi_store (rw)]|     o- luns ............................................................................. [LUNs: 1]|     | o- lun0 ............................. [block/iscsi_store (/dev/myvg/myvg) (default_tg_pt_gp)]|     o- portals ....................................................................... [Portals: 1]|       o- 172.25.250.10:3260 .................................................................. [OK]o- loopback ............................................................................ [Targets: 0]
/> exit
Global pref auto_save_on_exit=true
Configuration saved to /etc/target/saveconfig.json

使用 systemctl 命令重启 target 服务。这将重新启动 iSCSI 目标服务，以应用任何配置更改或修复可能的问题。使用 firewall-cmd 命令将 iscsi-target 服务添加到防火墙的永久规则中

[root@servera ~]# systemctl  restart  target.service
[root@servera ~]# firewall-cmd  --permanent  --add-service=iscsi-target
success
[root@servera ~]# firewall-cmd  --reload
success

启动器配置

配置 serverb 使其能连接在node1上提供的 iqn.2014-11.com.example:servera 并符合以下要
求：

iSCSI设备在系统启动的期间自动加载
块设备iSCSI上包含一个大小为 2100MiB 的分区，并格式化为 ext4
此分区挂载在 /mnt/data 上，同时在系统启动的期间自动挂载

[root@serverb ~]# yum search iscsi
[root@serverb ~]# yum -y install  iscsi-initiator-utils
[root@serverb ~]# cat /etc/iscsi/initiatorname.iscsi
[root@serverb ~]# echo "InitiatorName=iqn.2014-11.com.example:servera" > /etc/iscsi/initiatorname.iscsi[root@serverb ~]# cat /etc/iscsi/initiatorname.iscsi
InitiatorName=iqn.2014-11.com.example:servera
[root@serverb ~]# systemctl enable --now iscsid.service
Created symlink /etc/systemd/system/multi-user.target.wants/iscsid.service → /usr/lib/systemd/system/iscsid.service.
[root@serverb ~]# man iscsiadm

通过 iSCSI 发现操作找到了目标服务器的 IP 地址和名称，并使用 iscsiadm 命令登录到该目标。然后使用 lsblk 命令确认已连接的块设备

[root@serverb ~]#  iscsiadm --mode discoverydb --type sendtargets --portal   172.25.250.10 --discover
172.25.250.10:3260,1 iqn.2014-11.com.example:servera
[root@serverb ~]# man iscsiadm
[root@serverb ~]#  iscsiadm  --mode  node --targetname iqn.2014-11.com.example:servera --portal 172.25.
250.10:3260 -l
Logging in to [iface: default, target: iqn.2014-11.com.example:servera, portal: 172.25.250.10,3260]
Login to [iface: default, target: iqn.2014-11.com.example:servera, portal: 172.25.250.10,3260] successful.
[root@serverb ~]# lsblk
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda      8:0    0   3G  0 disk
vda    252:0    0  20G  0 disk
└─vda1 252:1    0  10G  0 part /
vdb    252:16   0   5G  0 disk
[root@serverb ~]# lsblk  --fs /dev/sda
NAME FSTYPE LABEL UUID MOUNTPOINT
sda

通过 fdisk 命令创建了一个新的分区表，并在 /dev/sda 上创建了一个 2.1GB 大小的主分区 /dev/sda1。然后使用 mkfs.ext4 命令在该分区上创建了 ext4 文件系统，验证分区和文件系统的创建情况。

[root@serverb ~]# fdisk /dev/sdaWelcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0xf9fbdda4.Command (m for help): n
Partition typep   primary (0 primary, 0 extended, 4 free)e   extended (container for logical partitions)
Select (default p):Using default response p.
Partition number (1-4, default 1):
First sector (2048-6291455, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-6291455, default 6291455): +2100MCreated a new partition 1 of type 'Linux' and of size 2.1 GiB.Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.[root@serverb ~]# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0    3G  0 disk
└─sda1   8:1    0  2.1G  0 part
vda    252:0    0   20G  0 disk
└─vda1 252:1    0   10G  0 part /
vdb    252:16   0    5G  0 disk
[root@serverb ~]# mkfs.ext4 /dev/sda1
mke2fs 1.44.6 (5-Mar-2019)
Creating filesystem with 537600 4k blocks and 134640 inodes
Filesystem UUID: 74d0c4f2-cc5f-46cc-a80d-5750690b5f56
Superblock backups stored on blocks:32768, 98304, 163840, 229376, 294912Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done[root@serverb ~]# lsblk --fs /dev/sda1
NAME FSTYPE LABEL UUID                                 MOUNTPOINT
sda1 ext4         74d0c4f2-cc5f-46cc-a80d-5750690b5f56

将 /dev/sda1 分区（文件系统类型为 ext4）挂载到 /mnt/data 目录，并将该挂载配置添加到 /etc/fstab 文件中，以便在系统启动时自动挂载该文件系统。

[root@serverb ~]# blkid  /dev/sda1
/dev/sda1: UUID="74d0c4f2-cc5f-46cc-a80d-5750690b5f56" TYPE="ext4" PARTUUID="f9fbdda4-01"
[root@serverb ~]# mkdir /mnt/data
[root@serverb ~]# echo  "UUID='74d0c4f2-cc5f-46cc-a80d-5750690b5f56'  /mnt/data  ext4 _netdev 0 0" >> /
etc/fstab
[root@serverb ~]# cat /etc/fstab#
# /etc/fstab
# Created by anaconda on Tue Oct 29 16:26:01 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
UUID=f7614c41-2835-4125-bb13-50772dc2f30c /                       xfs     defaults        0 0
servera.lab.example.com:/nfsshare /share                          nfs      defaults        0 0
UUID='74d0c4f2-cc5f-46cc-a80d-5750690b5f56'  /mnt/data  ext4 _netdev 0 0
[root@serverb ~]# mount  /mnt/data
[root@serverb ~]# df -ht ext4
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       2.0G  6.2M  1.9G   1% /mnt/data
[root@serverb ~]#