1。起因
有两台服务器分别安装部署了openstack的管理节点和计算节点，现在想给win7实例额外挂载E盘。
两台服务器安装系统时都是在配置完boot、swap和root后，将所有剩余磁盘空间分配给了home。因此没有剩余空间创建sdb。
2。解决方案
控制节点上部署cinder，并部署iscsi target，模拟出sdb；
计算节点上安装LVM作为存储节点给cinder用，计算节点挂载控制节点上模拟出的sdb；
这样dashboard上就能创建卷创建云盘，给win7实例当作E盘使用了。
cinder和LVM的安装部署见另一个随笔。本次只描述控制节点上如何部署iscsi target。
3。详细过程
a)安装：[root@controller ~]# yum install targetcli
b)新建文件夹：[root@controller ~]# mkdir /home/targetdisk
c)运行targetcli，依次执行如下命令创建iSCSI块设备：
[root@controller ~]# targetcli
/> cd backstores/fileio/
/backstores/fileio> create disk01 /home/targetdisk/disk01 40G
此时进入/home/targetdisk，就能看到大小是40G的文件disk01
（补充说明：如果如前面所述安装系统时有未分配的磁盘空间作为sdb，那么本步骤就不是进入fileio，而是进入block，然后用这个命令来创建块：create block01 /dev/sdb）
d)创建LIO iSCSI目标：
/> cd iscsi
/iscsi> create
Created target iqn.2003-01.org.linux-iscsi.controller.x8664:sn.f9144284c7ca.
Created TPG 1.
Global pref auto_add_default_portal=true
Created default portal listening on all IPs (0.0.0.0), port 3260.
/iscsi>
e)创建逻辑单元：
/iscsi> cd iqn.2003-01.org.linux-iscsi.controller.x8664:sn.f9144284c7ca/
/iscsi/iqn.20....f9144284c7ca> cd tpg1/luns
/iscsi/iqn.20...7ca/tpg1/luns> create /backstores/fileio/disk01
Created LUN 0.
f)创建网络入口：
/iscsi/iqn.20.../tpg1/portals> create 10.47.181.26
Using default IP port 3260
Could not create NetworkPortal in configFS
/iscsi/iqn.20.../tpg1/portals> ls
o- portals ............................................................................................................ [Portals: 1]
o- 0.0.0.0:3260 ............................................................................................................. [OK]
/iscsi/iqn.20.../tpg1/portals> delete 0.0.0.0 3260
Deleted network portal 0.0.0.0:3260
/iscsi/iqn.20.../tpg1/portals> create 10.47.181.26
Using default IP port 3260
Created network portal 10.47.181.26:3260.
g)创建访问控制列表：
/iscsi/iqn.20.../tpg1/portals> cd ../acls
/iscsi/iqn.20...7ca/tpg1/acls> ls
o- acls .................................................................................................................. [ACLs: 0]
/iscsi/iqn.20...7ca/tpg1/acls> create iqn.1994-05.com.redhat:91a579c4e39 （create后面的内容为何是这样的还不清楚，后面再研究）
Created Node ACL for iqn.1994-05.com.redhat:91a579c4e39
Created mapped LUN 0.
h)完成目标创建：
o- / ......................................................................................................................... [...]
o- backstores .............................................................................................................. [...]
| o- block .................................................................................................. [Storage Objects: 0]
| o- fileio ................................................................................................. [Storage Objects: 1]
| | o- disk01 ........................................................... [/home/targetdisk/disk01 (40.0GiB) write-back activated]
| | o- alua ................................................................................................... [ALUA Groups: 1]
| | o- default_tg_pt_gp ....................................................................... [ALUA state: Active/optimized]
| o- pscsi .................................................................................................. [Storage Objects: 0]
| o- ramdisk ................................................................................................ [Storage Objects: 0]
o- iscsi ............................................................................................................ [Targets: 1]
| o- iqn.2003-01.org.linux-iscsi.controller.x8664:sn.dd2dce582c05 ...................................................... [TPGs: 1]
| o- tpg1 ............................................................................................... [no-gen-acls, no-auth]
| o- acls .......................................................................................................... [ACLs: 1]
| | o- iqn.1994-05.com.redhat:91a579c4e39 ................................................................... [Mapped LUNs: 1]
| | o- mapped_lun0 ............................................................................... [lun0 fileio/disk01 (rw)]
| o- luns .......................................................................................................... [LUNs: 1]
| | o- lun0 ..................................................... [fileio/disk01 (/home/targetdisk/disk01) (default_tg_pt_gp)]
| o- portals .................................................................................................... [Portals: 1]
| o- 10.47.181.26:3260 ................................................................................................ [OK]
o- loopback ......................................................................................................... [Targets: 0]
i)设置认证凭证：
/> cd iscsi/
/iscsi> cd iqn.2003-01.org.linux-iscsi.controller.x8664:sn.f9144284c7ca/
/iscsi/iqn.20....f9144284c7ca> cd tpg1/
/iscsi/iqn.20...4284c7ca/tpg1> cd acls/iqn.1994-05.com.redhat:91a579c4e39/
/iscsi/iqn.20...t:91a579c4e39> set auth userid=IncomingUser
Parameter userid is now 'IncomingUser'.
/iscsi/iqn.20...t:91a579c4e39> set auth password=SomePassword
Parameter password is now 'SomePassword'.
/iscsi/iqn.20...t:91a579c4e39> set auth mutual_userid=OutgoingUser
Parameter mutual_userid is now 'OutgoingUser'.
/iscsi/iqn.20...t:91a579c4e39> set auth mutual_password=AnotherPassword
Parameter mutual_password is now 'AnotherPassword'.
下面开始配置计算节点（即合一的存储节点）
a)安装：[root@compute ~]# yum install iscsi-initiator-utils
b)配置：[root@compute ~]# vi /etc/iscsi/iscsid.conf
node.session.auth.authmethod = CHAP
node.session.auth.username = IncomingUser
node.session.auth.password = SomePassword
node.session.auth.username_in = OutgoingUser
node.session.auth.password_in = AnotherPassword
c)配置：[root@compute ~]# vi /etc/iscsi/initiatorname.iscsi
InitiatorName=iqn.1994-05.com.redhat:91a579c4e39
d)重启两个服务：
[root@compute ~]# systemctl restart iscsi
[root@compute ~]# systemctl restart iscsid
e)发现目标：[root@compute ~]# iscsiadm -m descovery -t sendtargets -p 10.47.181.26
f)登录目标：[root@compute ~]# iscsiadm -m node --login
g)察看磁盘吧：有sdb了：
[root@compute ~]# fdisk -l
磁盘 /dev/sda：1199.0 GB, 1198999470080 字节，2341795840 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 4096 字节
I/O 大小(最小/最佳)：4096 字节 / 4096 字节
磁盘标签类型：dos
磁盘标识符：0x00079f2a
设备 Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 2341795839 1169848320 8e Linux LVM
磁盘 /dev/mapper/centos-root：107.4 GB, 107374182400 字节，209715200 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 4096 字节
I/O 大小(最小/最佳)：4096 字节 / 4096 字节
磁盘 /dev/mapper/centos-swap：4294 MB, 4294967296 字节，8388608 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 4096 字节
I/O 大小(最小/最佳)：4096 字节 / 4096 字节
磁盘 /dev/mapper/centos-home：1086.3 GB, 1086253432832 字节，2121588736 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 4096 字节
I/O 大小(最小/最佳)：4096 字节 / 4096 字节
磁盘 /dev/sdb：42.9 GB, 42949672960 字节，83886080 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 512 字节
I/O 大小(最小/最佳)：512 字节 / 4194304 字节