Linux：iSCSI客户端扫描无法发现iSCSI服务端问题

配置环境信息：
Redhat7 target：192.168.23.10
Redhat7 initiator：192.168.23.20
Windows10 initiator：192.168.23.1

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问题：在192.168.23.20客户端扫描服务端，没有发现资源。

第一步：检查网络连通性，网络正常。

第二步：检查initiator文件中写入的客户端名称与target目录中acls的参数一致
[root@client Desktop]# cat /etc/iscsi/initiatorname.iscsi
InitiatorName=iqn.2003-01.org.linux-iscsi.localhost.x8664:sn.3c9133ae8aee:client

o- iscsi ............................................................................................................ [Targets: 1]
| o- iqn.2003-01.org.linux-iscsi.localhost.x8664:sn.3c9133ae8aee ....................................................... [TPGs: 1]
| o- tpg1 ............................................................................................... [no-gen-acls, no-auth]
| o- acls .......................................................................................................... [ACLs: 1]
| | o- iqn.2003-01.org.linux-iscsi.localhost.x8664:sn.3c9133ae8aee:client ................................... [Mapped LUNs: 1]

检查结果表示一致！

第三步：检查initiator的服务状态
[root@client Desktop]# systemctl restart iscsid
[root@client Desktop]# systemctl status iscsid
iscsid.service - Open-iSCSI
Loaded: loaded (/usr/lib/systemd/system/iscsid.service; enabled)
Active: active (running) since Fri 2020-02-07 08:42:17 EST; 10s ago
Docs: man:iscsid(8)
man:iscsiadm(8)
Process: 3950 ExecStop=/sbin/iscsiadm -k 0 2 (code=exited, status=0/SUCCESS)
Process: 3955 ExecStart=/usr/sbin/iscsid (code=exited, status=0/SUCCESS)
Main PID: 3957 (iscsid)
CGroup: /system.slice/iscsid.service
├─3956 /usr/sbin/iscsid
└─3957 /usr/sbin/iscsid

Feb 07 08:42:17 client systemd[1]: Starting Open-iSCSI...
Feb 07 08:42:17 client systemd[1]: Failed to read PID from file /var/run/iscsid.pid: Invali...ment
Feb 07 08:42:17 client iscsid[3956]: iSCSI daemon with pid=3957 started!
Feb 07 08:42:17 client systemd[1]: Started Open-iSCSI.
Hint: Some lines were ellipsized, use -l to show in full.

检查结果表示，运行正常！

第四步：检查target的服务状态
[root@localhost Desktop]# systemctl status targetd
targetd.service - targetd storage array API daemon
Loaded: loaded (/usr/lib/systemd/system/targetd.service; enabled)
Active: failed (Result: exit-code) since Fri 2020-02-07 07:45:27 EST; 11s ago
Process: 3597 ExecStart=/usr/bin/targetd (code=exited, status=255)
Main PID: 3597 (code=exited, status=255)

Feb 07 07:45:27 localhost.localdomain systemd[1]: Starting targetd storage array API daemon...
Feb 07 07:45:27 localhost.localdomain systemd[1]: Started targetd storage array API daemon.
Feb 07 07:45:27 localhost.localdomain targetd[3597]: CRITICAL:root:password not set in /etc/target/targetd.yaml
Feb 07 07:45:27 localhost.localdomain systemd[1]: targetd.service: main process exited, code=exited, status=255/n/a
Feb 07 07:45:27 localhost.localdomain systemd[1]: Unit targetd.service entered failed state.

iSCSI服务运行有报错，“ CRITICAL:root:password not set in /etc/target/targetd.yaml”。
查看该文件/etc/target/targetd.yaml，网上搜索该文件的相关配置文档，未果，后续待补充。
自我尝试配，未果。

此时，依据现有信息无法判断我的iSCSI target是否配置正常。
但是按照网络一个文档提示，该报错并不影响服务正常使用，initiator依然可以发现target。

第五步：在Windows 客户都尝试扫描 iSCSI共享资源，未果，没有搜索到。

此时，基本可以判断我的iSCSI target配置有问题，列出target所有目录进行检查。
[root@localhost Desktop]# targetcli
targetcli shell version 2.1.fb34
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.

/> ls
o- / ......................................................................................................................... [...]
o- backstores .............................................................................................................. [...]
| o- block .................................................................................................. [Storage Objects: 1]
| | o- desk0 ........................................................................... [/dev/md0 (40.0GiB) write-thru activated]
| o- fileio ................................................................................................. [Storage Objects: 0]
| o- pscsi .................................................................................................. [Storage Objects: 0]
| o- ramdisk ................................................................................................ [Storage Objects: 0]
o- iscsi ............................................................................................................ [Targets: 1]
| o- iqn.2003-01.org.linux-iscsi.localhost.x8664:sn.3c9133ae8aee ....................................................... [TPGs: 1]
| o- tpg1 ............................................................................................... [no-gen-acls, no-auth]
| o- acls .......................................................................................................... [ACLs: 1]
| | o- iqn.2003-01.org.linux-iscsi.localhost.x8664:sn.3c9133ae8aee:client ................................... [Mapped LUNs: 1]
| | o- mapped_lun0 ................................................................................. [lun0 block/desk0 (rw)]
| o- luns .......................................................................................................... [LUNs: 1]
| | o- lun0 ......................................................................................... [block/desk0 (/dev/md0)]
| o- portals .................................................................................................... [Portals: 1]
| o- 192.168.23.20:3260 ............................................................................................... [OK]
o- loopback ......................................................................................................... [Targets: 0]

逐行检查，问题发现了，提供访问共享资源的网卡地址写错了，正确的应该是192.168.23.10。

第六步：修改正确的TCP/IP地址。
通过help可得删除命令。
/iscsi/iqn.20.../tpg1/portals> help

GENERALITIES

略

Commands are built using the following syntax:

[TARGET_PATH] COMMAND_NAME [OPTIONS]

The TARGET_PATH indicates the path to run the command from.
If ommited, the command will be run from your current path.

The OPTIONS depend on the command. Please use help
COMMAND to get more information.

AVAILABLE COMMANDS

The following commands are available in the
current path:

• bookmarks action [bookmark]
• cd [path]
• create [ip_address] [ip_port]
• delete ip_address ip_port
• exit
• get [group] [parameter...]
• help [topic]
• ls [path] [depth]
• pwd
• refresh
• set [group] [parameter=value...]
• status

删除错误的TCP/IP信息：
/iscsi/iqn.20.../tpg1/portals> delete 192.168.23.20 3260
Deleted network portal 192.168.23.20:3260
添加正确的TCP/IP信息：
/iscsi/iqn.20.../tpg1/portals> create 192.168.23.10
Using default IP port 3260
Created network portal 192.168.23.10:3260.

重启服务，initiator再次尝试扫描。
[root@client Desktop]# iscsiadm -m discovery -t sendtargets -p 192.168.23.10
192.168.23.10:3260,1 iqn.2003-01.org.linux-iscsi.localhost.x8664:sn.3c9133ae8aee

总结，targetd.yaml关于root password的保存不影响iSCSI服务的正常运行。