Xen Live Migration Of An LVM-Based Virtual Machine With iSCSI On Debian Lenny - Page 2
4 Making The Shared Storage Available On server1 And server2
server1/server2:
On server1 and server2, we install the initiator:
aptitude install open-iscsi
Next we open /etc/iscsi/iscsid.conf...
vi /etc/iscsi/iscsid.conf
... and set node.startup to automatic:
[...] node.startup = automatic [...] |
Then we restart the initiator:
/etc/init.d/open-iscsi restart
Now we connect to the target (iscsi.example.com) and check what storage devices it has to offer:
iscsiadm -m discovery -t st -p 192.168.0.102
server1:~# iscsiadm -m discovery -t st -p 192.168.0.102
192.168.0.102:3260,1 iqn.2001-04.com.example:storage.lun1
server1:~#
iscsiadm -m node
server1:~# iscsiadm -m node
192.168.0.102:3260,1 iqn.2001-04.com.example:storage.lun1
server1:~#
The settings for the storage device iqn.2001-04.com.example:storage.lun1 on 192.168.0.102:3260,1 are stored in the file /etc/iscsi/nodes/iqn.2001-04.com.example:storage.lun1/192.168.0.102,3260,1/default. We need to set the username and password for the target in that file; instead of editing that file manually, we can use the iscsiadm command to do this for us:
iscsiadm -m node --targetname "iqn.2001-04.com.example:storage.lun1" --portal "192.168.0.102:3260" --op=update --name node.session.auth.authmethod --value=CHAP
iscsiadm -m node --targetname "iqn.2001-04.com.example:storage.lun1" --portal "192.168.0.102:3260" --op=update --name node.session.auth.username --value=someuser
iscsiadm -m node --targetname "iqn.2001-04.com.example:storage.lun1" --portal "192.168.0.102:3260" --op=update --name node.session.auth.password --value=secret
Now we can log in by running...
iscsiadm -m node --targetname "iqn.2001-04.com.example:storage.lun1" --portal "192.168.0.102:3260" --login
In the output of
fdisk -l
you should now find a new hard drive; that's our iSCSI storage device (in this example, it's named /dev/sdf on server1 and /dev/sdc on server2):
server1 output:
server1:~# fdisk -l
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00023cd1
Device Boot Start End Blocks Id System
/dev/sda1 * 1 62 497983+ 83 Linux
/dev/sda2 63 60801 487886017+ 5 Extended
/dev/sda5 63 60801 487885986 8e Linux LVM
Disk /dev/dm-0: 107.3 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/dm-0 doesn't contain a valid partition table
Disk /dev/dm-1: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/dm-1 doesn't contain a valid partition table
Disk /dev/sdf: 21.4 GB, 21474836480 bytes
64 heads, 32 sectors/track, 20480 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Disk identifier: 0x00000000
Disk /dev/sdf doesn't contain a valid partition table
server1:~#
server2 output:
server2:~# fdisk -l
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00036268
Device Boot Start End Blocks Id System
/dev/sda1 * 1 62 497983+ 83 Linux
/dev/sda2 63 60801 487886017+ 5 Extended
/dev/sda5 63 60801 487885986 8e Linux LVM
Disk /dev/dm-0: 107.3 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/dm-0 doesn't contain a valid partition table
Disk /dev/dm-1: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/dm-1 doesn't contain a valid partition table
Disk /dev/sdc: 21.4 GB, 21474836480 bytes
64 heads, 32 sectors/track, 20480 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Disk identifier: 0x00000000
Disk /dev/sdc doesn't contain a valid partition table
server2:~#
To use that device, we must format it (I want to create/use LVM-based virtual machines, therefore I format it as LVM (type 8e)):
server1:
fdisk /dev/sdf
server1:~# fdisk /dev/sdf
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x353f5965.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
The number of cylinders for this disk is set to 20480.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): <-- n
Command action
e extended
p primary partition (1-4)
<-- p
Partition number (1-4): <-- 1
First cylinder (1-20480, default 1): <-- ENTER
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-20480, default 20480): <-- ENTER
Using default value 20480
Command (m for help): <-- t
Selected partition 1
Hex code (type L to list codes): <-- L
0 Empty 1e Hidden W95 FAT1 80 Old Minix be Solaris boot
1 FAT12 24 NEC DOS 81 Minix / old Lin bf Solaris
2 XENIX root 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
3 XENIX usr 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
4 FAT16 <32M 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
5 Extended 41 PPC PReP Boot 85 Linux extended c7 Syrinx
6 FAT16 42 SFS 86 NTFS volume set da Non-FS data
7 HPFS/NTFS 4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
8 AIX 4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility
9 AIX bootable 4f QNX4.x 3rd part 8e Linux LVM df BootIt
a OS/2 Boot Manag 50 OnTrack DM 93 Amoeba e1 DOS access
b W95 FAT32 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
c W95 FAT32 (LBA) 52 CP/M 9f BSD/OS e4 SpeedStor
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
f W95 Ext'd (LBA) 54 OnTrackDM6 a5 FreeBSD ee EFI GPT
10 OPUS 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
11 Hidden FAT12 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
12 Compaq diagnost 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
14 Hidden FAT16 <3 61 SpeedStor a9 NetBSD f4 SpeedStor
16 Hidden FAT16 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fd Linux raid auto
18 AST SmartSleep 65 Novell Netware b8 BSDI swap fe LANstep
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid ff BBT
1c Hidden W95 FAT3 75 PC/IX
Hex code (type L to list codes): <-- 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): <-- w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
server1:~#
Afterwards, the output of
fdisk -l
should look as follows:
server1:~# fdisk -l
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00023cd1
Device Boot Start End Blocks Id System
/dev/sda1 * 1 62 497983+ 83 Linux
/dev/sda2 63 60801 487886017+ 5 Extended
/dev/sda5 63 60801 487885986 8e Linux LVM
Disk /dev/dm-0: 107.3 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/dm-0 doesn't contain a valid partition table
Disk /dev/dm-1: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/dm-1 doesn't contain a valid partition table
Disk /dev/sdf: 21.4 GB, 21474836480 bytes
64 heads, 32 sectors/track, 20480 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Disk identifier: 0x353f5965
Device Boot Start End Blocks Id System
/dev/sdf1 1 20480 20971504 8e Linux LVM
server1:~#
Since this is a shared storage, /dev/sdc on server2 should now also contain an LVM partition, /dev/sdc1:
server2:
fdisk -l
server2:~# fdisk -l
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00036268
Device Boot Start End Blocks Id System
/dev/sda1 * 1 62 497983+ 83 Linux
/dev/sda2 63 60801 487886017+ 5 Extended
/dev/sda5 63 60801 487885986 8e Linux LVM
Disk /dev/dm-0: 107.3 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/dm-0 doesn't contain a valid partition table
Disk /dev/dm-1: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/dm-1 doesn't contain a valid partition table
Disk /dev/sdc: 21.4 GB, 21474836480 bytes
64 heads, 32 sectors/track, 20480 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Disk identifier: 0x353f5965
Device Boot Start End Blocks Id System
/dev/sdc1 1 20480 20971504 8e Linux LVM
server2:~#
Now I initialize /dev/sdf1 on server1 for LVM usage and create the volume group vg_xen on it:
server1:
pvcreate /dev/sdf1
vgcreate vg_xen /dev/sdf1
In order to make the new volume group available on server2, we must first log out of iSCSI and then back in:
server2:
iscsiadm -m node --targetname "iqn.2001-04.com.example:storage.lun1" --portal "192.168.0.102:3260" --logout
iscsiadm -m node --targetname "iqn.2001-04.com.example:storage.lun1" --portal "192.168.0.102:3260" --login
Then run...
vgscan
server2:~# vgscan
Reading all physical volumes. This may take a while...
Found volume group "vg_xen" using metadata type lvm2
Found volume group "vg0" using metadata type lvm2
server2:~#
... and...
vgchange -a y
server2:~# vgchange -a y
0 logical volume(s) in volume group "vg_xen" now active
2 logical volume(s) in volume group "vg0" now active
server2:~#
... to activate the vg_xen volume group on server2.
