Virtualt3Tipsandtricks - Notes on work done at the BNL Tier 3

allowing X windows to be open from with sudo command

• In order to allow sudo virt-manager to open a window - need to define environmental variable XAUTHORITY

export XAUTHORITY=~benjamin/.Xauthority

Adding disk space to an existing virtual machine

• Use dd to create a file to be used as disk space for a virtual machine

dd if=/dev/zero of=/var/lib/xen/images/diskimage_100GB.img oflag=direct bs=1M count=100K

• Create ext3 file system

/sbin/mkfs.ext3 -b 4096 -O dir_index /var/lib/xen/images/diskimage_100GB.img
mke2fs 1.39 (29-May-2006)
/var/lib/xen/images/diskimage_100GB.img is not a block special device.
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
13107200 inodes, 26214400 blocks
1310720 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
800 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks: 
   32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
   4096000, 7962624, 11239424, 20480000, 23887872

Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 37 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

• Modify VM configuration file that you want to use add disk

disk = [ "tap:aio:/var/lib/xen/images/sl53-x86_64_v2_srm.img,xvda,w",
         "tap:aio:/var/lib/xen/images/diskimage_100GB.img,xvdb,w" ]

• Startup VM

Inside of VM :

* First create a physical volume using pvcreate

[root@atlast3vm9 ~]# pvcreate /dev/xvdb
  Physical volume "/dev/xvdb" successfully created
[root@atlast3vm9 ~]# pvscan
  PV /dev/xvda2   VG VolGroup00      lvm2 [19.41 GB / 0    free]
  PV /dev/xvdb                       lvm2 [100.00 GB]
  Total: 2 [119.41 GB] / in use: 1 [19.41 GB] / in no VG: 1 [100.00 GB]

• Now a Volume group

[root@atlast3vm9 ~]# vgcreate VolGrpSRM /dev/xvdb
  Volume group "VolGrpSRM" successfully created
[root@atlast3vm9 ~]# vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "VolGrpSRM" using metadata type lvm2
  Found volume group "VolGroup00" using metadata type lvm2

• Determine how big is the volume group with vgdisk and grep commands

[root@atlast3vm9 ~]# vgdisplay VolGrpSRM | grep 'Total PE'
  Total PE              25599

• Now use the PE value and lvcreate to create a logical volume

[root@atlast3vm9 ~]# lvcreate -n LVSRM -l 25599 VolGrpSRM
  Logical volume "LVSRM" created
[root@atlast3vm9 ~]# lvscan
  ACTIVE            '/dev/VolGrpSRM/LVSRM' [100.00 GB] inherit
  ACTIVE            '/dev/VolGroup00/LogVol00' [18.38 GB] inherit
  ACTIVE            '/dev/VolGroup00/LogVol01' [1.03 GB] inherit

• Create a file ext3 file system on volume

[root@atlast3vm9 ~]# mkdir -p /data/srm
[root@atlast3vm9 ~]# emacs -nw /etc/fstab
[root@atlast3vm9 ~]# cat /etc/fstab
/dev/VolGroup00/LogVol00 /                       ext3    defaults        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/VolGroup00/LogVol01 swap                    swap    defaults        0 0
/dev/VolGrpSRM/LVSRM    /data/srm               ext3     defaults       0 0

• Edit /etc/fstab adding /dev/VolGrpSRM/LVSRM to /data/srm mount point and mount it

[root@atlast3vm9 ~]# mkdir -p /data/srm
[root@atlast3vm9 ~]# emacs -nw /etc/fstab
[root@atlast3vm9 ~]# cat /etc/fstab
/dev/VolGroup00/LogVol00 /                       ext3    defaults        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/VolGroup00/LogVol01 swap                    swap    defaults        0 0
/dev/VolGrpSRM/LVSRM    /data/srm               ext3     defaults       0 0
[root@atlast3vm9 ~]# mount -t ext3 /dev/VolGrpSRM/LVSRM    /data/srm

Cloning existing virtual machine

sudo virt-clone -o sl53-x86_64_v2 -n sl53-x86_64_v2_clone1 -f /var/lib/xen/images/sl53-x86_64_v2_clone1.img
Cloning from /var/lib/xen/images/sl53-x86_64_v2.img to /var/lib/xen/images/sl53-x86_64_v2_clone1.img
Cloning domain...                                                                                |  20 GB     06:14