CentOS下ISCSI共享存储配置

ISCSI共享存储

​ ISCSI，小型计算机系统接口，又称为IP-SAN，是一种基于因特网及SCSI-3协议下的存储技术，它可以共享镜像文件（*.img）、分区（partition）、物理硬盘和逻辑卷等。现在使用ISCSI技术实现局域网内共享物理磁盘和磁盘分区。

1. 环境准备

1.1硬件环境

• 两台CentOS7.6的机器，一台额外安装2个硬盘的机器，用作存储设备。
• 两台机器均可访问Internet

1.2 软件环境

​ 对额外挂载两个磁盘的机器，中的一个磁盘做分区操作

• 磁盘分区

  [root@server ~]# fdisk /dev/sdc
  Welcome to fdisk (util-linux 2.23.2).
  
  Changes will remain in memory only, until you decide to write them.
  Be careful before using the write command.
  
  Device does not contain a recognized partition table
  Building a new DOS disklabel with disk identifier 0xf9c6e7e6.
  
  Command (m for help): m
  Command action
     a   toggle a bootable flag
     b   edit bsd disklabel
     c   toggle the dos compatibility flag
     d   delete a partition
     g   create a new empty GPT partition table
     G   create an IRIX (SGI) partition table
     l   list known partition types
     m   print this menu
     n   add a new partition
     o   create a new empty DOS partition table
     p   print the partition table
     q   quit without saving changes
     s   create a new empty Sun disklabel
     t   change a partition's system id
     u   change display/entry units
     v   verify the partition table
     w   write table to disk and exit
     x   extra functionality (experts only)
  
  Command (m for help): n
  Partition type:
     p   primary (0 primary, 0 extended, 4 free)
     e   extended
  Select (default p): p
  Partition number (1-4, default 1): 
  First sector (2048-20971519, default 2048): 
  Using default value 2048
  Last sector, +sectors or +size{K,M,G} (2048-20971519, default 20971519): 
  Using default value 20971519
  Partition 1 of type Linux and of size 10 GiB is set
  
  Command (m for help): w
  The partition table has been altered!
  
  Calling ioctl() to re-read partition table.
  Syncing disks.
  [root@server ~]# 
  

2.ISCSI配置

2.1 服务器端配置

• 安装scsi-target-utils和scsi-target-utils

  [root@server ~]# yum -y install epel-release
  [root@server ~]# yum -y install scsi-target-utils
  [root@server ~]# chkconfig tgtd on
  Note: Forwarding request to 'systemctl enable tgtd.service'.
  Created symlink from /etc/systemd/system/multi-user.target.wants/tgtd.service to /usr/lib/systemd/system/tgtd.service.
  [root@server ~]# service tgtd start
  Redirecting to /bin/systemctl start tgtd.service
  [root@server ~]# ss -tunlp | grep tgt
  tcp    LISTEN     0      128       *:3260                  *:*                   users:(("tgtd",pid=12504,fd=6))
  tcp    LISTEN     0      128      :::3260                 :::*                   users:(("tgtd",pid=12504,fd=7))
  [root@server ~]# 
  

• 编辑/etc/tgt/targets.conf

  追加以下内容

  <target iqn.2022.04.com.rac:iscsi.disk>
          backing-store /dev/sdb
          backing-store /dev/sdc1
          incominguser iscsiuser iscsiuser
          initiator-address 192.168.100.0/24
  </target>
  

  backiing-store:共享的存储路径

  incominguser:该target的账密

  initiator-address:可以登录该target的IP或者IP段

  target命名规则：iqn.年份-月份.域名反写.设备识别

• 关闭防火墙

  [root@server ~]# systemctl disable firewalld.service
  

  编辑/etc/selinux/config,把enforce更改成disabled

  [root@server ~]# vim /etc/selinux/config 
  

  # This file controls the state of SELinux on the system.
  # SELINUX= can take one of these three values:
  #     enforcing - SELinux security policy is enforced.
  #     permissive - SELinux prints warnings instead of enforcing.
  #     disabled - No SELinux policy is loaded.
  SELINUX=disabled
  # SELINUXTYPE= can take one of three values:
  #     targeted - Targeted processes are protected,
  #     minimum - Modification of targeted policy. Only selected processes are protected. 
  #     mls - Multi Level Security protection.
  SELINUXTYPE=targeted
  
  

2.2 客户端配置

• 安装iscsi-initiator-utils

  [root@node1 ~]# yum -y install iscsi-initiator-utils
  

• 设置开机自启动

  [root@node1 ~]# chkconfig iscsi on
  [root@node1 ~]# chkconfig iscsid on
  

• 配置initiator文件

  vim /etc/iscsi/initiatorname.iscsi
  

  InitiatorName=iqn.2022.04.com.rac:iscsi.disk
  

• 配置iscsid.conf文件:

  [root@node1 ~]# vim /etc/iscsi/iscsid.conf
  

  把以下配置项的注释取消掉，并填入用户名和密码

  # To enable CHAP authentication set node.session.auth.authmethod
  # to CHAP. The default is None.
  node.session.auth.authmethod = CHAP
  
  # To configure which CHAP algorithms to enable set
  # node.session.auth.chap_algs to a comma seperated list.
  # The algorithms should be listen with most prefered first.
  # Valid values are MD5, SHA1, SHA256
  # The default is MD5.
  #node.session.auth.chap_algs = SHA256,SHA1,MD5
  
  # To set a CHAP username and password for initiator
  # authentication by the target(s), uncomment the following lines:
  node.session.auth.username = iscsiuser
  node.session.auth.password = iscsiuser
  

• 启动客户端服务

  [root@node1 ~]# service iscsi start
  [root@node1 ~]# service iscsid start
  

• 设置开机自连接

  开机启动iscsi服务

  [root@node1 ~]# chkconfig iscsid on
  

  查找target,如果查找失败，重启服务器端

  [root@node1 ~]# iscsiadm -m discovery -t st -p 192.168.100.188
  192.168.100.188:3260,1 iqn.2022.04.com.rac:iscsi.disk
  

  手动登录到共享的ISCSI存储

  [root@node1 ~]# iscsiadm -m node -T iqn.2022.04.com.rac:iscsi.disk -p 192.168.100.188 -l
  Logging in to [iface: default, target: iqn.2022.04.com.rac:iscsi.disk, portal: 192.168.100.188,3260] (multiple)
  Login to [iface: default, target: iqn.2022.04.com.rac:iscsi.disk, portal: 192.168.100.188,3260] successful.
  [root@node1 ~]# 
  

  设置开机自启动连接target

  [root@node1 ~]# iscsiadm -m node -T iqn.2022.04.com.rac:iscsi.disk -p 192.168.100.188 --op update -n node.startup -v automatic
  

3.问题记录

3.1共享存储变动

​ 共享的存储发生变化，但是客户端却没有发生相应变化，可以采取重启target的服务，然后清理客户端缓存，重启相应服务，等待几分钟重新查找，登录即可。

• 重启服务器端服务

  [root@server ~]# service tgtd start
  

• 清理客户端缓存

  [root@server ~]# rm -rf /var/lib/iscsi/nodes/*
  [root@server ~]# rm -rf /var/lib/iscsi/send_targets/*
  

  注：如果只清理缓存，却没登出和删除发现target记录,就直接登录，会报以下错误

  root@node1 ~]# iscsiadm -m node -T iqn.2022.04.com.rac:iscsi.disk -p 192.168.100.188 -l
  iscsiadm: No records found
  

• 登出target

  [root@node1 ~]# iscsiadm -m node -T iqn.2022.04.com.rac:iscsi.disk -p 192.168.100.188 -u
  

• 删除发现target记录

  [root@node1 ~]# iscsiadm -m node -T iqn.2022.04.com.rac:iscsi.disk -p 192.168.100.188 -o delete
  

• 重启客户端服务

  [root@node1 ~]# systemctl restart iscsid
  [root@node1 ~]# systemctl restart iscsi
  

• 重新查找target

  [root@node1 ~]# iscsiadm -m discovery -t st -p 192.168.100.188
  192.168.100.188:3260,1 iqn.2022.04.com.rac:iscsi.disk
  

  现在，共享的存储可以像本地磁盘一样使用了！