4. Centos 7 - iSCSI

由 datahunter 在二, 21/11/2017 - 09:47 發表

最後更新: 2019-06-05

Target

# Diagram

123.10(Client) --> 123.55(Server)
client1.local      server1.local

# Create image for target

truncate -s 1g /home/iscsi2.img

# Install tools

yum install targetcli -y

* tree-based layout
* a front end for viewing, editing, and saving the configuration of the Linux-IO (lio)

LIO and targetcli uses configFS for its configuration. All storage objects can be accessed and exported

mount | grep configfs

configfs on /sys/kernel/config type configfs (rw,relatime)

# interactive shell

targetcli

# 建立 backstores

# type: block, fileio, pscsi, ramdisk
# fileio: Allows files to be treated as disk images
# block: local disk block
# pscsi: local SCSI device of any type to be shared
# ramdisk: kernel memory to be shared as a block SCSI device
# Default: write_back=true

/backstores/fileio

/backstores/fileio> create u16 /home/pxe/iscsi/u16.img 20G

Using buffered mode.
Created fileio u16.

/backstores/fileio> status

Status for /backstores/fileio: 1 Storage Object

/backstores/fileio> ls

o- fileio ....................................................................................................... [1 Storage Object]
  o- u16 .............................................................................. [20.0G, /home/pxe/iscsi/u16.img, not in use]

# 建立 tpg (Target Portal Group)

Target Portal Group

a set of one or more storage system network interfaces that can be used for an iSCSI session between an initiator and a target.

The iSCSI protocol allows only one session between a specific iSCSI initiator port and a single portal group on the target.

# 它會自動建立 portals (0.0.0.0:3260)

# IQN with TargetName

/iscsi

create iqn.2017-11.local.server1:t1

naming-authority = server.local -> local.server

# 設定 network

/iscsi

iqn.2017-11.local.server1:t1/tpg1/portals

delete ip_address=0.0.0.0 ip_port=3260

create 192.168.123.55

# 建立 lun

把 image file 做 lun

/iscsi/iqn.../tpg1/luns

create /backstores/fileio/shareddata

# 設定 ACL (對應 client 的 '/etc/iscsi/initiatorname.iscsi')

/iscsi/iqn.../tpg1/acls

create iqn.2017-11.local.client1

Remark

# Disable automatically maps LUNs to any created ACL

/> set global auto_add_mapped_luns=false

# 人手加 lun

/iscsi/target_iqn_name/tpg1/acls/initiator_iqn_name/

create mapped_lun=next_sequential_LUN_number [write_protect=1]

# save setting

/saveconfig

Remark

* exit 時亦會 autosave

* Last 10 configs saved in /etc/target/backup

Configuration saved to /etc/target/saveconfig.json

# start & enable service

systemctl start target

systemctl enable target

# checking

yum -y install net-tools # 獲得 netstat

netstat -antp | grep 3260

netstat -ntp | grep 3260
tcp        0 131120 192.168.123.55:3260     192.168.123.56:51400    ESTABLISHED -

# fw

firewall-cmd --permanent --add-port=3260/tcp

firewall-cmd --reload

Block Device Lun

為 Block Device 建立 uuid / label

parted /dev/vdb

mklabel gpt

mkpart iscsi-disk 0% 100%

Model: Virtio Block Device (virtblk)
Disk /dev/vdb: 10.7GB
Sector size (logical/physical): 4096B/4096B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name        Flags
 1      1049kB  10.7GB  10.7GB               iscsi-disk

blkid /dev/vdb1

/dev/vdb1: PARTLABEL="iscsi-disk" PARTUUID="e1937114-8bd9-413e-acef-5f4f118d2a7d"

/dev/disk/by-partlabel:

iscsi-disk

/dev/disk/by-partuuid:

e1937114-8bd9-413e-acef-5f4f118d2a7d

targetcli 設定

/backstores/block

create iscsi-disk /dev/disk/by-partlabel/iscsi-disk

Created block storage object iscsi-disk using /dev/disk/by-partlabel/iscsi-disk.

cd /iscsi/iqn.../tpg1/luns/

create /backstores/block/iscsi-disk

Disable Login

* Per targets setting

* Warning: With this setting everybody that knows the iqn of one of your clients (initiators) can access the target.

# Disable authentication so that any initiator can access LUN.

/iscsi/iqn.../tpg1> set attribute authentication=0

# Checking

/iscsi/iqn.../tpg1> get attribute authentication

authentication=0

Server 設定 Credentials

/iscsi/.../tpg1> get auth

/iscsi/.../tpg1> set auth userid=<username in target>

/iscsi/.../tpg1> set auth password=<password in target>

Backup & Restore Setting

# Backup

# the file may contain cleartext passwords

# Default file location: /etc/target/saveconfig.json

targetctl save [config-file]

# Restore

# Removes any existing configuration and replaces it with the configuration described in the file

targetctl restore [config-file]

# Remove

# Removes any existing configuration from the running kernel target

targetctl clear

# File

ls /sys/kernel/config/target/

core  iscsi  version

cat version

Target Engine Core ConfigFS Infrastructure v4.1.0 on Linux/x86_64 on 3.10.0-693.17.1.el7.x86_64

Server Enable / Disable target

Linux Side: Initiator

# Server disable target
Dec  7 13:31:41 seafile iscsid: connect to 192.168.123.41:3260 failed (Connection refused)
Dec  7 13:31:44 seafile iscsid: connect to 192.168.123.41:3260 failed (Connection refused)
Dec  7 13:31:47 seafile iscsid: connect to 192.168.123.41:3260 failed (Connection refused)
...

# Server enable target
Dec  7 13:31:50 seafile iscsid: connection1:0 is operational after recovery (28 attempts)

NAS - Synology

設定 Step

1. Lun <- # data

2. Target <- # Login

3. Target 設定有什麼 LUN

Initiator

There are two ways of establishing connection to the storage target using iscsiadm utility:

sendtargets discovery (多數用呢個方法)
static target login

# Install initiator

yum install -y iscsi-initiator-utils

# Check version

iscsiadm -V

iscsiadm version 6.2.0.874-2

# 設定 Initiator 的 IQN 名稱 (必須)

cat /etc/iscsi/initiatorname.iscsi

InitiatorName=iqn.local.seafile

# change to the same IQN you set on the iSCSI target server

# 修改後要 restart iscsid

# 設定 Login 資料 (隨意)

/etc/iscsi/iscsid.conf

# The default is None
node.session.auth.authmethod = CHAP

# Login 資料
node.session.auth.username = username
node.session.auth.password = password

Remark: 在 Server 設定 login

/iscsi/iqn.../tpg1

set auth userid=user
set auth password=password

# Start & Enable servcie

systemctl start iscsid

systemctl enable iscsid

ps aux | grep [i]scsi

root      3310  0.0  0.0  31516   340 ?        Ss   May30   0:24 /usr/sbin/iscsid
root      3311  0.0  1.3  42536 13920 ?        S<Ls May30   0:00 /usr/sbin/iscsid
root      3342  0.0  0.0      0     0 ?        S<   May30   0:00 [iscsi_eh]

# 常用 Opt 縮寫

-m => --mode node | session | discovery | ...

-t => --type # type: sendtargets | fw | iSNS. This option is only valid for discovery mode.

-p => --portal IP

-T => --targetname iqn... # used along with --portal in node mode

# Discovery

iscsiadm -m discovery -t sendtargets -p 192.168.123.41

192.168.123.41:3260,1 iqn.local.nas:tgt-seafile-bak

# List discovery 了的 node records

iscsiadm -m node

iscsiadm: No records found

192.168.123.41:3260,1 iqn.local.nas:tgt-seafile-bak

iscsiadm -m node -p <ipaddress>

i.e.

iscsiadm -m node -p 192.168.123.41

# BEGIN RECORD 6.2.0.874-10
node.name = iqn.local.nas:tgt-seafile-bak
node.tpgt = 1
node.startup = automatic
node.leading_login = No
...
node.session.auth.authmethod = None
node.session.auth.username = <empty>
node.session.auth.password = <empty>
...

iscsiadm -m node -T iqn.local.nas:tgt-seafile-bak

# BEGIN RECORD 6.2.0.874-10
node.name = iqn.local.nas:tgt-seafile-bak
node.tpgt = 1
node.startup = automatic
node.leading_login = No
...

說明

node.leading_login = No

For "automatic" startup nodes, (node.startup)

"Yes" will try logins on each available iface until one succeeds, and then stop.

"No" will try logins on all available ifaces simultaneously. (default)

# login to the target

# Login to All target

iscsiadm -m node --login

Logging in to [iface: default, target: iqn.2017-11.local.server1:t1, portal: 192.168.123.55,3260] (multiple)
Login to [iface: default, target: iqn.2017-11.local.server1:t1, portal: 192.168.123.55,3260] successful.

# Login portal 內個別 target

iscsiadm -m node -T iqn.local.nas:tgt-seafile-bak --login

Logging in to [iface: default, target: iqn.local.nas:tgt-seafile-bak, portal: 192.168.123.41,3260] (multiple)
Login to [iface: default, target: iqn.local.nas:tgt-seafile-bak, portal: 192.168.123.41,3260] successful.

iscsiadm -m node -p 192.168.123.41 --login

# session

# -S, --show When displaying records, do not hide masked values, such as the CHAP secret

iscsiadm -m session

iscsiadm: No active sessions.

tcp: [2] 192.168.123.41:3260,1 iqn.local.nas:tgt-seafile-bak (non-flash)

'[2]' 是 session id 來

-r, --sid=sid

#查看某 session 的詳細資料

iscsiadm -m session -r 2

# -s, --stats # Display session statistics.

iscsiadm -m session -r 2 -s

Stats for session [sid: 2, target: iqn.local.nas:tgt-seafile-bak, portal: 192.168.123.41,3260]
iSCSI SNMP:
        txdata_octets: 2352
        rxdata_octets: 2272
        noptx_pdus: 0
        scsicmd_pdus: 2
        tmfcmd_pdus: 0
        login_pdus: 0
        text_pdus: 0
        dataout_pdus: 0
        logout_pdus: 0
        snack_pdus: 0
        noprx_pdus: 0
        scsirsp_pdus: 2
        tmfrsp_pdus: 0
        textrsp_pdus: 0
        datain_pdus: 2
        logoutrsp_pdus: 0
        r2t_pdus: 0
        async_pdus: 0
        rjt_pdus: 0
        digest_err: 0
        timeout_err: 0
iSCSI Extended:
        tx_sendpage_failures: 0
        rx_discontiguous_hdr: 0
        eh_abort_cnt: 0

# Checking Block Device

# 成功 Login 後就會有新的 Block Device

lsblk --scsi | grep iscsi

# NAME HCTL       TYPE VENDOR   MODEL             REV TRAN
sda  12:0:0:0   disk SYNOLOGY iSCSI Storage    4.0  iscsi

設定 Initiator 對某 target 的 login

# CHAP 必須有寫

iscsiadm --mode node -T iqn.local.nas:tgt-seafile-bak \
-o update -n node.session.auth.authmethod -v CHAP

# 設定 Username & Password

iscsiadm --mode node -T iqn.local.nas:tgt-seafile-bak \
-o update -n node.session.auth.username -v myuser

iscsiadm --mode node -T iqn.local.nas:tgt-seafile-bak \
-o update -n node.session.auth.password -v mypass

# Login

iscsiadm -m node -T iqn.local.nas:tgt-seafile-bak --login

Initiator automatic login

# 設定: All the targets

/etc/iscsi/iscsid.conf

node.startup = manual|automatic

# 設定: All the ports on a target

iscsiadm --mode node -T targetname -o update -n node.startup -v manual|automatic

# 設定: A specific port on a target

iscsiadm --mode node -T targetname -p ip:port -o update -n node.startup -v manual|automatic

Initiator Logout

CLI

iscsiadm -m node -T targetname -p ipaddress -u

-u, --logout # only valid for node and session mode

i.e.

# 用 "iscsiadm -m session" 找出當先 session

iscsiadm -m node -p 192.168.123.41 -u

Logging out of session [sid: 5, target: iqn.local.nas:tgt-seafile-bak, portal: 192.168.123.41,3260]
Logout of [sid: 5, target: iqn.local.nas:tgt-seafile-bak, portal: 192.168.123.41,3260] successful.

# checking

lsblk --scsi | grep iscsi

# logout all target

iscsiadm -m node -u

Discovering new LUNs

當 Server / NAS 為 target 加了新 LUN 時

iscsiadm -m session --rescan

Rescanning session [sid: 5, target: iqn.local.nas:tgt-seafile-bak, portal: 192.168.123.41,3260]

iscsiadm -m session -r SID --rescan

lsblk --scsi | grep iscsi

sda  12:0:0:0   disk SYNOLOGY iSCSI Storage    4.0  iscsi

targets 與 portals 的目錄

# This directory contains the nodes with their targets

# Centos 7

ls -R /var/lib/iscsi/nodes

/var/lib/iscsi/nodes:
iqn.local.nas:seafile-bak-tgt

/var/lib/iscsi/nodes/iqn.local.nas:seafile-bak-tgt:
192.168.123.41,3260,1

/var/lib/iscsi/nodes/iqn.local.nas:seafile-bak-tgt/192.168.123.41,3260,1:
default # 此 target 的 setting

# This directory contains the portals

ls -R /var/lib/iscsi/send_targets

192.168.123.41,3260

/var/lib/iscsi/send_targets:
192.168.123.41,3260

/var/lib/iscsi/send_targets/192.168.123.41,3260:
iqn.local.nas:seafile-bak-tgt,192.168.123.41,3260,1,default

# link to /var/lib/iscsi/nodes/iqn.local.nas:seafile-bak-tgt/192.168.123.41,3260,1

Discover - Remove an iSCSI device discovery entry

iscsiadm -m node -o delete -p 192.168.123.55

ls -R /var/lib/iscsi/nodes

iscsiadm -m discoverydb -o delete -t sendtargets -p 192.168.123.55

ls -R /var/lib/iscsi/send_targets

Discover - Discovering new LUNs

# rescan

iscsiadm -m session --rescan

Rescanning session [sid: 11, target: iqn.2017-11.local.server1:t1, portal: 192.168.123.55,3260]

# 查看找到什麼

lsblk --scsi | grep iscsi

Discover - discoverydb

SendTargets

A native iSCSI protocol which allows each iSCSI target to send a list of available targets to the initiator.

discoverydb record

A discoverydb record holds together the information required to discover the target including portal address

discovery mechanism

SendTargets in this case, credentials etc.

View the configuration in the discoverydb record

iscsiadm -m discoverydb

192.168.123.41:3260 via sendtargets

ls -1R /etc/iscsi/send_targets

/etc/iscsi/send_targets:
192.168.123.41,3260

/etc/iscsi/send_targets/192.168.123.41,3260:
iqn.test,192.168.123.41,3260,1,default
st_config

iscsiadm -m discoverydb -t st -p 192.168.123.41

(相當於 "cat /etc/iscsi/send_targets/192.168.123.41,3260/st_config")

# BEGIN RECORD 2.0-873
discovery.startup = manual
discovery.type = sendtargets
discovery.sendtargets.address = 192.168.123.41
discovery.sendtargets.port = 3260
discovery.sendtargets.auth.authmethod = None
discovery.sendtargets.auth.username = <empty>
discovery.sendtargets.auth.password = <empty>
discovery.sendtargets.auth.username_in = <empty>
discovery.sendtargets.auth.password_in = <empty>
discovery.sendtargets.timeo.login_timeout = 15
discovery.sendtargets.use_discoveryd = No
discovery.sendtargets.discoveryd_poll_inval = 30
discovery.sendtargets.reopen_max = 5
discovery.sendtargets.timeo.auth_timeout = 45
discovery.sendtargets.timeo.active_timeout = 30
discovery.sendtargets.iscsi.MaxRecvDataSegmentLength = 32768
# END RECORD

discovery 與 discoverydb mode 的不同

discovery

* uses the iscsid.conf settings

* Performs a discovery operation

discoverydb

* Updates or queries the Open-iSCSI database records

(/etc/iscsi/send_targets/<IP>,<PORT>/)

* uses the discovery record settings if it exists

iSCSI Checksum

有兩種 checksum, 分別是

header digest
data digest

Default: CRC32C algorithm (32 bit) - A digest to detect errors that occur at this iSCSI layer.

affect performance => Disable the iSCSI digest

( relying upon TCP and Ethernet error detection mechanisms )

Bit errors in the header portion of the PDU are more problematic because there is no trail to expose the corrupted data

If the header error occurs during a write transaction,

the original data will be unchanged while a "random" block of data will be overwritten with the update value

PDU (Protocol Data Unit): The initiator and target divide their communications into messages.

The term "iSCSI protocol data unit" (iSCSI PDU) is used for these messages.

------------

# List the current parameters

iscsiadm -m node -T iqn.local.nas:tgt-seafile-bak

node.conn[0].iscsi.HeaderDigest = CRC32C

# Server 啟用了 header 及 data digest 後. 如果 Client 沒有啟動, 那 Login 會見到

iscsiadm -m node -T iqn.local.nas:tgt-seafile-bak --login

Logging in to [iface: default, target: iqn.local.nas:tgt-seafile-bak, portal: 192.168.123.41,3260] (multiple)
iscsiadm: Could not login to [iface: default, target: iqn.local.nas:tgt-seafile-bak, portal: 192.168.123.41,3260].
iscsiadm: initiator reported error (19 - encountered non-retryable iSCSI login failure)
iscsiadm: Could not log into all portals

# Enable HeaderDigest 及 DataDigest

# Disable: -v None

iscsiadm --mode node -T iqn.local.nas:tgt-seafile-bak -o update -n node.conn[0].iscsi.HeaderDigest -v CRC32C

iscsiadm --mode node -T iqn.local.nas:tgt-seafile-bak -o update -n node.conn[0].iscsi.DataDigest -v CRC32C

# Centos7 - iscsiadm version 6.2.0.874-10 有 bug

iscsiadm: Cannot modify node.conn[0].iscsi.DataDigest. Invalid param name.

# Verify

# -PN # info level: 0 - 3

# 要 2 才見到 HeaderDigest, DataDigest

iscsiadm -m session -P2 | grep Digest

HeaderDigest: CRC32C
DataDigest: None

Cheat List

iscsiadm -m discovery -t st -p 192.168.123.41

iscsiadm -m node -T iqn.test -o update -n 'node.session.auth.authmethod' -v CHAP

iscsiadm -m node -T iqn.test -o update -n 'node.session.auth.username' -v myusr

iscsiadm -m node -T iqn.test -o update -n 'node.session.auth.password' -v mypw

iscsiadm -m node -T iqn.test -o update -n 'node.conn[0].iscsi.HeaderDigest' -v CRC32C

iscsiadm -m node -T iqn.test -l

iscsiadm -m session

iscsiadm -m node -T iqn.test -u

成功 log

Logging in to [iface: default, target: iqn.test, portal: 192.168.123.41,3260] (multiple)
Login to [iface: default, target: iqn.test, portal: 192.168.123.41,3260] successful.

fstab Setting

Mount iscsi drive at boot case the system halts(CentOS 7)

add _netdev to mount

This way the mount point will be mounted only after the network start correctly.

iSCSI MultiSession(multipath) Setup

要用到 Multipaht I/O (MPIO)

Step 0: Connect the LUN

iscsiadm -m session

Step 1: Install multipath package

# C 8

yum install device-mapper-multipath

dm-multipath # kernel module
multipath # Command used for viewing/listing multipath devices
multipathd # daemon that moitors path
kpartx # command used to create device mapper entries

Checking

modprobe dm_multipath

lsmod | grep dm_multipath

dm_multipath           40960  0
dm_mod                151552  1 dm_multipath

Step 3: 設定 multipath

/etc/multipath.conf

defaults {
  checker_timeout 600
  # friendly names like /dev/mapper/mpath0
  user_friendly_names yes
}
blacklist {
  device {
    vendor "QEMU"
    product '*'
  }
}

systemctl enable multipathd

systemctl start multipathd

Checking

multipath -ll

multipathd -k

# ID_SERIAL

scsi_id -x -g -u -s /block/sdb

lsscsi

Step 4:

Update mounts and fstab from original /dev/sdX[0-9] path to "/dev/mapper/XXXXXXp[0-9]"

adding "nofail" to the /etc/fstab

Step 5: rebuild initramfs

# Debian/Ubuntu:

update-initramfs -u

# CentOS/RedHat

dracut -f

More info.

VMWare ESXi5.5 (and earlier versions) only supports 512 bytes Sector Size iSCSI LUN

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夢想家

4. Centos 7 - iSCSI

Target

Block Device Lun

Disable Login

Server 設定 Credentials

Backup & Restore Setting

Server Enable / Disable target

NAS - Synology

Initiator

設定 Initiator 對某 target 的 login

Initiator automatic login

Initiator Logout

Discovering new LUNs

targets 與 portals 的目錄

Discover - Remove an iSCSI device discovery entry

Discover - Discovering new LUNs

Discover - discoverydb

iSCSI Checksum

Cheat List

fstab Setting

iSCSI MultiSession(multipath) Setup

More info.