设备方式实现共享sicsi

iSCSI技术是一种由IBM公司研究开发的，是一个供硬件设备使用的可以在IP协议的上层运行的SCSI指令集，
这种指令集合可以实现在IP网络上运行SCSI协议，使其能够在诸如高速千兆以太网上进行路由选择。iSCSI
技术是一种新储存技术，该技术是将现有SCSI接口与以太网络(Ethernet)技术结合，使服务器可与使用IP
网络的储存装置互相交换资料。

服务端：
fdisk /var/vdb   #建立一个分区vda2，此处大小为1G
partprobe
yum install targetcli.noarch
systemctl start target
targetcli
/> /backstores/block create westos:storage1 /dev/vdb2  ##和逻辑卷建立联系，/dev/vdb2用westos：storage1表示
Created block storage object westos:storage1 using /dev/vdb2.
/> /iscsi create iqn.2017-12.com.example:storage1      ##每个发起端和目标需要唯一名进行标示
Created target iqn.2017-12.com.example:storage1.
Created TPG 1.
/> /iscsi/iqn.2017-12.com.example:storage1/tpg1/acls  create iqn.2017-12.com.example:westoskey   ##创建客户端连接服务端密钥
Created Node ACL for iqn.2017-12.com.example:westoskey
/> /iscsi/iqn.2017-12.com.example:storage1/tpg1/luns  create /backstores/block/westos:storage1  ##在单元中创建逻辑单元号
Created LUN 0.
Created LUN 0->0 mapping in node ACL iqn.2017-12.com.example:westoskey
/> /iscsi/iqn.2017-12.com.example:storage1/tpg1/portals create 172.25.254.11    ##建立网关连接，即目标门户
Using default IP port 3260
Created network portal 172.25.254.11:3260.
/> exit

firewall-cmd --permanent --add-port=3260/tcp    ##将共享磁盘的共享端口加入火墙策略
firewall-cmd --reload

客户端：
yum search iscsi   ##寻找iscsi服务
yum install iscsi-initiator-utils.x86_64 -y
systemctl start iscsi
[root@client ~]# vim /etc/iscsi/initiatorname.iscsi

InitiatorName=iqn.2017-12.com.example:westoskey

systemctl restart iscsi
[root@client ~]# iscsiadm -m discovery -t st -p 172.25.254.11  ##发现设备
172.25.254.11:3260,1 iqn.2017-12.com.example:storage1
[root@client ~]# iscsiadm -m node -T iqn.2017-12.com.example:storage1 -p 172.25.254.11 -l   ##登陆
Logging in to [iface: default, target: iqn.2017-12.com.example:storage1, portal: 172.25.254.11,3260] (multiple)
Login to [iface: default, target: iqn.2017-12.com.example:storage1, portal: 172.25.254.11,3260] successful.

fdisk -l   ##查看设备
Disk /dev/sda   ##发现多出一个设备
fdisk /dev/sda    ##建立最大分区
mkfs.xfs /dev/sda1
mount /dev/sda1 /mnt/
cd /mnt
[root@server ~]# mount /dev/vdb2 /mnt
mount: /dev/vdb2 is already mounted or /mnt busy     ##由于客户端已挂载，所以服务端无法挂载，同一个设备的原因
yum install tree
tree /var/lib/iscsi/
设定开机自起：
[root@client ~]# blkid
/dev/vda1: UUID="9bf6b9f7-92ad-441b-848e-0257cbb883d1" TYPE="xfs"
/dev/vdb1: UUID="SIaPf4-OdHu-OzAW-NlQG-vZ3D-X8ZO-1FK3Ih" TYPE="LVM2_member"
/dev/mapper/vg0-vo: UUID="12294be2-bdad-4817-b162-038e22313d9f" TYPE="ext4"
/dev/sda1: UUID="926567a2-281d-4144-98ac-9fe50b4224b0" TYPE="xfs"
[root@client ~]# vim /etc/fstab
UUID="926567a2-281d-4144-98ac-9fe50b4224b0"     /mnt  xfs   defaults,_netdev  0 0    ##当没有写,_netdev时，需要进入紧急模式将/etc/fstab中写的内容注释掉，才能重启
[root@client ~]# mount -a
[root@client ~]# reboot
[root@foundation9 ~]# rht-vmctl poweroff desktop    ##第一次启动时需要先关机再开启
Powering off desktop..
[root@foundation9 ~]# rht-vmctl start desktop
Starting desktop.

服务端删除：
umount /mnt   ##先卸载
[root@client ~]# vim /etc/fstab    ##再删除开机自起的配置内容
tree /var/lib/iscsi    ##查看
iscsiadm -m node -T iqn.2017-12.com.example:storage1 -p 172.25.254.109 -u   ##退出
iscsiadm -m node -T iqn.2017-12.com.example:storage1 -p 172.25.254.109 -o delete   ##删除
tree /var/lib/iscsi
fdisk -l
systemctl restart iscsi
[root@client ~]# fdisk -l    ##重起后sda将不存在

服务端删除：
targetcli
/> clearconfig confirm=true

扩展：
1.
服务端：
先创建一个lvm分区，将原来的删掉
fdisk /dev/vdb
/dev/vdb2            2048     2099199     1048576   8e  Linux LVM
partprobe
pvcreate /dev/vdb2
vgcreate iscsi_vg /dev/vdb1
vgdisplay   ##找到剩余空间的参数
lvcreate -l 255 -n iscsi_lv iscsi_vg

targetcli    ##在服务端建立共享lvm磁盘
/> /backstores/block create westos:storage1 /dev/iscsi_vg/iscsi_lv
Created block storage object westos:storage1 using /dev/iscsi_vg/iscsi_lv.
/> /iscsi create iqn.2017-12.com.example:storage1
Created target iqn.2017-12.com.example:storage1.
Created TPG 1.
/> iscsi/iqn.2017-12.com.example:storage1/tpg1/acls create iqn.2017-12.com.example:key1
Created Node ACL for iqn.2017-12.com.example:key1
/> /iscsi/iqn.2017-12.com.example:storage1/tpg1/luns create /backstores/block/westos:storage1
Created LUN 0.
Created LUN 0->0 mapping in node ACL iqn.2017-12.com.example:key1
/> iscsi/iqn.2017-12.com.example:storage1/tpg1/portals create 172.25.254.11
Using default IP port 3260
Created network portal 172.25.254.11:3260.
/> exit

客户端：
[root@client ~]# tree /var/lib/iscsi
/var/lib/iscsi
|-- ifaces
|-- isns
|-- nodes
|-- send_targets
|-- slp
`-- static

6 directories, 0 files   ##需要将原来的删除干净

[root@client ~]# vim /etc/iscsi/initiatorname.iscsi   ##修改密码文件
InitiatorName=iqn.2017-12.com.example:key1
systemctl restart iscsid.service
systemctl restart iscsi
[root@client ~]# iscsiadm -m discovery -t st -p 172.25.254.11   ##发现服务，-m侦测target，-t通过iscsi协议，-p指定target的ip和port，不写port默认为3260
172.25.254.11:3260,1 iqn.2017-12.com.example:storage1
[root@client ~]# iscsiadm -m node -T iqn.2017-12.com.example:storage1 -p 172.25.254.11 -l   ##登陆服务
Logging in to [iface: default, target: iqn.2017-12.com.example:storage1, portal: 172.25.254.11,3260] (multiple)
Login to [iface: default, target: iqn.2017-12.com.example:storage1, portal: 172.25.254.11,3260] successful.

2.
服务端扩展
fdisk /dev/vdb
/dev/vdb2           2048     2099199     1048576   8e  Linux LVM
/dev/vdb3        2099200     4196351     1048576   8e  Linux LVM
partprobe     ##增加一个lvm分区,为vdb3
[root@server ~]# pvcreate /dev/vdb3
Physical volume "/dev/vdb3" successfully created
[root@server ~]# vgextend iscsi_vg /dev/vdb3
Volume group "iscsi_vg" successfully extended
[root@server ~]# lvextend -L 1500M /dev/iscsi_vg/iscsi_lv
Extending logical volume iscsi_lv to 1.46 GiB
Logical volume iscsi_lv successfully resized
[root@server ~]# lvs  ##查看
LV        VG       Attr       LSize Pool Origin Data%  Move Log Cpy%Sync Convert
iscsi_lv iscsi_vg -wi-ao---- 1.46g

客户端同步
[root@client ~]# iscsiadm -m node -T iqn.2017-12.com.example:storage1 -p 172.25.254.11 -u
Logging out of session [sid: 2, target: iqn.2017-12.com.example:storage1, portal: 172.25.254.11,3260]
Logout of [sid: 2, target: iqn.2017-12.com.example:storage1, portal: 172.25.254.11,3260] successful.
[root@client ~]# iscsiadm -m node -T iqn.2017-12.com.example:storage1 -p 172.25.254.11 -l   ##需要先退出再登陆客户端才等出现扩展
Logging in to [iface: default, target: iqn.2017-12.com.example:storage1, portal: 172.25.254.11,3260] (multiple)
Login to [iface: default, target: iqn.2017-12.com.example:storage1, portal: 172.25.254.11,3260] successful.
[root@client ~]# fdisk -l
Disk /dev/sda: 1572 MB