Sysadmin/Migrate virtual machine - Revision history

Bernie: /* Importing a VM from existing disk files */

2022-02-27T23:21:43Z

Importing a VM from existing disk files

← Older revision		Revision as of 19:21, 27 February 2022
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	=== Importing a VM from existing disk files ===		=== Importing a VM from existing disk files ===

	# virt-install -v --accelerate --nographics --vcpus 2 ~~--name lightwave~~ --ram 1024 --os-type linux --os-variant=ubuntu20.04 --network bridge:br0 --disk vol=boot/~~lightwave~~-boot.img,bus=virtio --disk vol=nvme-pool/~~lightwave~~-root,bus=virtio --import		# virt-install -v --accelerate --nographics --vcpus 2 --ram 1024 --os-type linux --os-variant=ubuntu20.04 --network bridge:br0 --disk vol=boot/NEWVM-boot.img,bus=virtio --disk vol=nvme-pool/NEWVM-root,bus=virtio --name NEWVM --import

	The VM will boot and probably fail to mount the root because the UUID changed.		The new VM will boot and probably fail to mount the root because the UUID changed.
	You can fix this by dropping into grub the usual way:		You can fix this by dropping into grub the usual way:

			* virsh start --console NEWVM
	* press ESC before the kernel starts		* press ESC before the kernel starts
	* press e to edit a menu entry		* press e to edit a menu entry
	* modify the kernel command line (for example, root=/dev/vdb)		* modify the kernel command line (for example, root=/dev/vdb)
	* hit ctrl-x to boot		* hit ctrl-x to boot

			After booting, remember to update your grub.cfg and test it:

			# update-grub
			# reboot

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

Bernie at 23:15, 27 February 2022

2022-02-27T23:15:31Z

← Older revision		Revision as of 19:15, 27 February 2022
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	# virt-install -v --accelerate --nographics --vcpus 2 --name lightwave --ram 1024 --os-type linux --os-variant=ubuntu20.04 --network bridge:br0 --disk vol=boot/lightwave-boot.img,bus=virtio --disk vol=nvme-pool/lightwave-root,bus=virtio --import		# virt-install -v --accelerate --nographics --vcpus 2 --name lightwave --ram 1024 --os-type linux --os-variant=ubuntu20.04 --network bridge:br0 --disk vol=boot/lightwave-boot.img,bus=virtio --disk vol=nvme-pool/lightwave-root,bus=virtio --import

			The VM will boot and probably fail to mount the root because the UUID changed.
			You can fix this by dropping into grub the usual way:

			* press ESC before the kernel starts
			* press e to edit a menu entry
			* modify the kernel command line (for example, root=/dev/vdb)
			* hit ctrl-x to boot

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

Bernie at 23:09, 27 February 2022

2022-02-27T23:09:59Z

@@ Line 6: / Line 6: @@
   # virsh vol-create-as boot new.img 1G --format raw
   # virsh vol-upload --pool boot new.img existing.img
 === How to migrate a file-based guest to LVM (online method) ===

Bernie at 22:26, 27 February 2022

2022-02-27T22:26:40Z

← Older revision		Revision as of 18:26, 27 February 2022
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	=== Alternative to convert file based VM to block based LVM ~~(Assumes server is treehouse)~~ ===		=== Alternative to convert file based VM to block based LVM ===

	Stop the VM		Stop the VM

Bernie at 22:23, 27 February 2022

2022-02-27T22:23:02Z

← Older revision		Revision as of 18:23, 27 February 2022
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			=== Importing an existing disk image into libvirt ===

			Let's assume you already have a disk file and you want to add it to a pool.
			There doesn't seem to be a direct way to do this with virsh, but you can create a blank disk and then copy your image into it:

			# virsh vol-create-as boot new.img 1G --format raw
			# virsh vol-upload --pool boot new.img existing.img

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

Bernie at 23:13, 14 January 2012

2012-01-14T23:13:30Z

← Older revision		Revision as of 19:13, 14 January 2012
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	=== How to migrate a file-based guest to LVM (online method) ===		=== How to migrate a file-based guest to LVM (online method) ===

	* First, ~~create~~ the ~~logical volume~~ and ~~attach it to the running VM~~:		* First, take a copy of the kernel and initrd:

	treehouse# scp VMNAME:/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/

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

	treehouse# virsh vol-create-as treehouse VMNAME-root 10G		treehouse# virsh vol-create-as treehouse VMNAME-root 10G
	treehouse# virsh attach-disk VMNAME /dev/treehouse/VMNAME-root vdc		treehouse# virsh attach-disk VMNAME /dev/treehouse/VMNAME-root vdc
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	=== How to migrate a file-based guest to LVM (offline method) ===		=== How to migrate a file-based guest to LVM (offline method) ===

			This method works by taking down the virtual machine during the migration and mounting the
			partition inside the hard drive image. Mounting qcow2 files require a fancier method.

	* Determine the offset of the root partition within the raw disk image:		* Determine the offset of the root partition within the raw disk image:

Bernie at 06:14, 23 January 2011

2011-01-23T06:14:02Z

← Older revision		Revision as of 02:14, 23 January 2011
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	mount -o loop,offset=$((63 * 512)) vm.img /mnt/		mount -o loop,offset=$((63 * 512)) vm.img /mnt/

	* Then create an LV and copy over everything as in the online case		* Then, create an LV and copy over everything as in the online case

			virsh vol-create-as treehouse VMNAME-root 10G
			virsh attach-disk rt /dev/treehouse/VMNAME-root vdc
			mkfs.ext4 -L rt-root -O flex_bg,extent,uninit_bg,sparse_super /dev/treehouse/VMNAME-root
			tune2fs -c -1 -i 0 /dev/treehouse/VMNAME-root
			mkdir /mnt2/VMNAME-root
			mount /dev/treehouse/VMNAME-root /mnt2/VMNAME-root/
			rsync -HAXphax --numeric-ids --delete /mnt/VMNAME-root/ /mnt2/VMNAME-root/

	=== How to migrate an LVM-based guest to another host ===		=== How to migrate an LVM-based guest to another host ===

Bernie at 06:06, 23 January 2011

2011-01-23T06:06:29Z

← Older revision		Revision as of 02:06, 23 January 2011
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	* First, create the logical volume and attach it to the running VM:		* 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		* 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:		* 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>		<os>
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	<kernel>/srv/vm/kernel/ubuntu/vmlinuz-2.6.31-22-server</kernel>		<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>		<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'/>		<boot dev='hd'/>
	</os>		</os>
Line 33:		Line 33:
	...		...
	<disk type='block' device='disk'>		<disk type='block' device='disk'>
	<source dev='/dev/treehouse/~~lightwave~~-root'/>		<source dev='/dev/treehouse/VMNAME-root'/>
	<target dev='vda' bus='virtio'/>		<target dev='vda' bus='virtio'/>
	</disk>		</disk>
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	* Reboot		* 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) ===		=== How to migrate a file-based guest to LVM (offline method) ===

Bernie at 06:03, 23 January 2011

2011-01-23T06:03:23Z

← Older revision		Revision as of 02:03, 23 January 2011
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	treehouse# scp lightwave:/boot/{vmlinuz,initrd}-2.6.31-22-server /srv/vm/kernel/ubuntu/		treehouse# scp lightwave:/boot/{vmlinuz,initrd}-2.6.31-22-server /srv/vm/kernel/ubuntu/
	treehouse# virsh vol-create-as treehouse lightwave 10G		treehouse# virsh vol-create-as treehouse lightwave-root 10G
	treehouse# virsh attach-disk lightwave /dev/treehouse/lightwave-root vdc		treehouse# virsh attach-disk lightwave /dev/treehouse/lightwave-root vdc
	treehouse# virsh console lightwave		treehouse# virsh console lightwave

Smparrish at 15:24, 16 August 2010

2010-08-16T15:24:47Z

@@ Line 1: / Line 1: @@
-== How to migrate a file-based guest to LVM (online method) ==
+=== How to migrate a file-based guest to LVM (online method) ===
 * First, create the logical volume and attach it to the running VM:
@@ Line 44: / Line 44: @@
   #treehouse virsh start lightwave --console
-== How to migrate a file-based guest to LVM (offline method) ==
+=== How to migrate a file-based guest to LVM (offline method) ===
 * Determine the offset of the root partition within the raw disk image:
@@ Line 56: / Line 56: @@
 * Then create an LV and copy over everything as in the online case
-== How to migrate an LVM-based guest to another host ==
+=== How to migrate an LVM-based guest to another host ===
 (untested procedure)
@@ Line 76: / Line 76: @@
 Make sure you pass all the fancy switches to rsync or you'll loose
 information on the copy.