iSCSI

We will need to use SCSI device so we can fully trace it in exercise 5. Xen hypervisor supports SCSI emulation, but only by emulating outdated LSI 53c895a controller which is not supported by Solaris. However, we can create iSCSI devices in Dom0 and supply them to virtual machines. The following guide is created for Debian 7 which uses iSCSI Enterprise Target. Recent Linux kernels replaced it with LIO stack.

• Install IET packages:

  # aptitude install iscsitarget iscsitarget-dkms

• Create logical disks for virtual machines. They would be LVM volumes /dev/mapper/vgmain-sol11--base--lab and /dev/mapper/vgmain-centos7--base--lab in our example.
• Create targets in /etc/iet/ietd.conf file by adding following lines:

  Target iqn.2154-04.tdc.r520:storage.lab5-sol11-base
      Lun 0 Path=/dev/mapper/vgmain-sol11--base--lab,Type=blockio
  
  Target iqn.2154-04.tdc.r520:storage.lab5-centos7-base
      Lun 0 Path=/dev/mapper/vgmain-centos7--base--lab,Type=blockio

  Note that target names should match DNS name of a host which provides them.
• Configure /etc/iet/initiators.allow file to forbid Solaris access to disk allocated for CentOS machine and vice versa. Delete or comment out ALL ALL line and add lines with target names and IP addresses of corresponding machines:

  iqn.2154-04.tdc.r520:storage.lab5-sol11-base    192.168.50.179
  iqn.2154-04.tdc.r520:storage.lab5-centos7-base  192.168.50.171

• Restart IET daemon:

  # /etc/init.d/iscsitarget restart

• Configure Solaris initiator. 192.168.50.116 is an IP address of our Dom0 system which provides iSCSI targets.

  # iscsiadm add discovery-address 192.168.50.116
  # iscsiadm modify discovery -t enable
  # svcadm restart svc:/network/iscsi/initiator:default

• Similarly configure CentOS initiator:

  # yum install iscsi-initiator-utils
  # systemctl enable iscsid
  # systemctl start iscsid
  # iscsiadm -m discovery -t sendtargets -p 192.168.50.116
  # iscsiadm -m node --login