Linux：iSCSI客戶端掃描無法發現iSCSI服務端問題

配置環境信息：
Redhat7 target：192.168.23.10
Redhat7 initiator：192.168.23.20
Windows10 initiator：192.168.23.1

問題：在192.168.23.20客戶端掃描服務端，沒有發現資源。

第一步：檢查網絡連通性，網絡正常。

第二步：檢查initiator文件中寫入的客戶端名稱與target目錄中acls的參數一致
[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]

檢查結果表示一致！

第三步：檢查initiator的服務狀態
[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.

檢查結果表示，運行正常！

第四步：檢查target的服務狀態
[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服務運行有報錯，“ CRITICAL:root:password not set in /etc/target/targetd.yaml”。
查看該文件/etc/target/targetd.yaml，網上搜索該文件的相關配置文檔，未果，后續待補充。
自我嘗試配，未果。

此時，依據現有信息無法判斷我的iSCSI target是否配置正常。
但是按照網絡一個文檔提示，該報錯并不影響服務正常使用，initiator依然可以發現target。

第五步：在Windows 客戶都嘗試掃描 iSCSI共享資源，未果，沒有搜索到。

此時，基本可以判斷我的iSCSI target配置有問題，列出target所有目錄進行檢查。
[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]

逐行檢查，問題發現了，提供訪問共享資源的網卡地址寫錯了，正確的應該是192.168.23.10。

第六步：修改正確的TCP/IP地址。
通過help可得刪除命令。
/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

刪除錯誤的TCP/IP信息：
/iscsi/iqn.20.../tpg1/portals> delete 192.168.23.20 3260
Deleted network portal 192.168.23.20:3260
添加正確的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.

重啟服務，initiator再次嘗試掃描。
[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

總結，targetd.yaml關于root password的保存不影響iSCSI服務的正常運行。