Sysadmin/Migrate virtual machine: Difference between revisions

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* First, create the logical volume and attach it to the running VM:

treehouse# scp ~~lightwave~~:/boot/{vmlinuz,initrd}-2.6.31-22-server /srv/vm/kernel/ubuntu/

treehouse# scp VMNAME:/boot/{vmlinuz,initrd}-2.6.31-22-server /srv/vm/kernel/ubuntu/

treehouse# virsh vol-create-as treehouse ~~lightwave~~-root 10G

treehouse# virsh vol-create-as treehouse VMNAME-root 10G

treehouse# virsh attach-disk ~~lightwave~~ /dev/treehouse/~~lightwave~~-root vdc

treehouse# virsh attach-disk VMNAME /dev/treehouse/VMNAME-root vdc

treehouse# virsh console ~~lightwave~~

treehouse# virsh console VMNAME

* From within the VM, format the new volume and move things over

~~lightwave~~# mkfs.ext4 -L ~~lightwave~~-root -O flex_bg,extent,uninit_bg,sparse_super /dev/vdc

VMNAME# mkfs.ext4 -L VMNAME-root -O flex_bg,extent,uninit_bg,sparse_super /dev/vdc

~~lightwave~~# tune2fs -c -1 -i 0 /dev/vdc

VMNAME# tune2fs -c -1 -i 0 /dev/vdc

~~lightwave~~# mount /dev/vdc /mnt

VMNAME# mount /dev/vdc /mnt

~~lightwave~~# rsync -PHAXphax --numeric-ids --delete / /mnt/

VMNAME# rsync -PHAXphax --numeric-ids --delete / /mnt/

~~lightwave~~# vim /mnt/etc/fstab

VMNAME# vim /mnt/etc/fstab

~~lightwafe~~# umount /mnt

VMNAME# umount /mnt

~~lightwave~~# ^D

VMNAME# ^D

* Then edit the VM configuration to make it boot without GRUB, using externally provided kernel and initrd:

treehouse# virsh edit ~~lightwave~~

treehouse# virsh edit VMNAME

<os>

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<kernel>/srv/vm/kernel/ubuntu/vmlinuz-2.6.31-22-server</kernel>

<initrd>/srv/vm/kernel/ubuntu/initrd.img-2.6.31-22-server</initrd>

<cmdline>console=tty0 console=ttyS0,115200n8 vga=normal root=LABEL=~~lightwave~~-root ro</cmdline>

<cmdline>console=tty0 console=ttyS0,115200n8 vga=normal root=LABEL=VMNAME-root ro</cmdline>

</os>

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...

</disk>

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* Reboot

#treehouse virsh destroy ~~lightwave~~

#treehouse virsh destroy VMNAME

#treehouse virsh start ~~lightwave~~ --console

#treehouse virsh start VMNAME --console

=== How to migrate a file-based guest to LVM (offline method) ===

@@ Line 3: / Line 3: @@
 * First, create the logical volume and attach it to the running VM:
-  treehouse# scp lightwave:/boot/{vmlinuz,initrd}-2.6.31-22-server /srv/vm/kernel/ubuntu/
+  treehouse# scp VMNAME:/boot/{vmlinuz,initrd}-2.6.31-22-server /srv/vm/kernel/ubuntu/
-  treehouse# virsh vol-create-as treehouse lightwave-root 10G
+  treehouse# virsh vol-create-as treehouse VMNAME-root 10G
-  treehouse# virsh attach-disk lightwave /dev/treehouse/lightwave-root vdc
+  treehouse# virsh attach-disk VMNAME /dev/treehouse/VMNAME-root vdc
-  treehouse# virsh console lightwave
+  treehouse# virsh console VMNAME
 * From within the VM, format the new volume and move things over
-  lightwave# mkfs.ext4 -L lightwave-root -O flex_bg,extent,uninit_bg,sparse_super /dev/vdc
+  VMNAME# mkfs.ext4 -L VMNAME-root -O flex_bg,extent,uninit_bg,sparse_super /dev/vdc
-  lightwave# tune2fs -c -1 -i 0 /dev/vdc
+  VMNAME# tune2fs -c -1 -i 0 /dev/vdc
-  lightwave# mount /dev/vdc /mnt
+  VMNAME# mount /dev/vdc /mnt
-  lightwave# rsync -PHAXphax --numeric-ids --delete / /mnt/
+  VMNAME# rsync -PHAXphax --numeric-ids --delete / /mnt/
-  lightwave# vim /mnt/etc/fstab
+  VMNAME# vim /mnt/etc/fstab
-  lightwafe# umount /mnt
+  VMNAME# umount /mnt
-  lightwave# ^D
+  VMNAME# ^D
 * Then edit the VM configuration to make it boot without GRUB, using externally provided kernel and initrd:
-  treehouse# virsh edit lightwave
+  treehouse# virsh edit VMNAME
    <os>
@@ Line 26: / Line 26: @@
      <kernel>/srv/vm/kernel/ubuntu/vmlinuz-2.6.31-22-server</kernel>
      <initrd>/srv/vm/kernel/ubuntu/initrd.img-2.6.31-22-server</initrd>
-     <cmdline>console=tty0 console=ttyS0,115200n8 vga=normal root=LABEL=lightwave-root ro</cmdline>
+     <cmdline>console=tty0 console=ttyS0,115200n8 vga=normal root=LABEL=VMNAME-root ro</cmdline>
      <boot dev='hd'/>
    </os>
@@ Line 33: / Line 33: @@
      ...
      <disk type='block' device='disk'>
-       <source dev='/dev/treehouse/lightwave-root'/>
+       <source dev='/dev/treehouse/VMNAME-root'/>
        <target dev='vda' bus='virtio'/>
      </disk>
@@ Line 41: / Line 41: @@
 * Reboot
-  #treehouse virsh destroy lightwave
+  #treehouse virsh destroy VMNAME
-  #treehouse virsh start lightwave --console
+  #treehouse virsh start VMNAME --console
 === How to migrate a file-based guest to LVM (offline method) ===