Difference between revisions of "Moving an existing install into (or out of) a virtual machine"

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(Set up a shared folder: some cleanup)
(revised, improved)
Line 37: Line 37:
 
  # arch-chroot /mnt
 
  # arch-chroot /mnt
  
Reinstall Syslinux or GRUB, using the [[Beginners'_Guide#Install_and_configure_a_bootloader|instructions]] from the Beginners' Guide.
+
Reinstall either Syslinux or GRUB, using the [[Beginners'_Guide#Install_and_configure_a_bootloader|instructions]] from the Beginners' Guide. Don't forget to update the configuration file (i.e. {{ic|syslinux.cfg}} or {{ic|grub.cfg}}).
  
 
=== Adjust the fstab ===
 
=== Adjust the fstab ===
  
Since your entire root tree has been transferred to a single partition, edit the [[fstab]] file to reflect the right partition. Check with {{ic|blkid}}.
+
Since your entire root tree has been transferred to a single partition, edit the [[fstab]] file to reflect the right partition. Check with {{ic|blkid}} (since {{ic|lsblk}} is not very useful inside a chroot).
  
 
=== Re-generate the initramfs image ===
 
=== Re-generate the initramfs image ===
Line 48: Line 48:
  
 
  # mkinitcpio -p linux  
 
  # mkinitcpio -p linux  
 +
# poweroff
 +
 +
And that's about it.
 +
 +
You'll most likely need to set up the network, since the virtual machine was probably piggybacking on the host OS's network settings. See [[Beginners'_Guide#Configure_the_network|Configure the network]] from the Beginners' Guide.
  
 
== Moving into a VM  ==
 
== Moving into a VM  ==
Line 98: Line 103:
 
Hook up the converted file from above, and the latest Arch Linux ISO into the virtual CD-ROM. Then start the virtual machine and [[chroot]] into it:
 
Hook up the converted file from above, and the latest Arch Linux ISO into the virtual CD-ROM. Then start the virtual machine and [[chroot]] into it:
  
  # mount /dev/sda1
+
  # mount /dev/sda1 /mnt
 
  # arch-chroot /mnt
 
  # arch-chroot /mnt
  
Reinstall Syslinux or GRUB, using the [[Beginners'_Guide#Install_and_configure_a_bootloader|instructions]] from the Beginners' Guide.
+
Reinstall either Syslinux or GRUB, using the [[Beginners'_Guide#Install_and_configure_a_bootloader|instructions]] from the Beginners' Guide. Just don't forget to update its configuration file:
 +
 
 +
* For Syslinux, it should be {{ic|1=APPEND root=/dev/sda1 ro}} in {{ic|syslinux.cfg}}.
 +
 
 +
* For GRUB, it's recommended that you automatically re-generate a {{ic|grub.cfg}}.
  
 
=== Adjust the fstab ===
 
=== Adjust the fstab ===
Line 113: Line 122:
 
=== Disable any Xorg-related files ===
 
=== Disable any Xorg-related files ===
  
Having an {{ic|nvidia}} entry (or {{ic|nouveau}}, {{ic|radeon}}, {{ic|intel}}, etc) in the {{ic|Device}} section from one of the Xorg configuration files will inhibit the {{ic|startx}} command, since you will be using ''emulated'' hardware (including the video card). So it's recommended that you move/rename or delete them:
+
Having an {{ic|nvidia}} entry (or {{ic|nouveau}}, {{ic|radeon}}, {{ic|intel}}, etc) in the {{ic|Device}} section from one of the Xorg configuration files will inhibit the {{ic|startx}} command, since you will be using ''emulated'' hardware (including the video card). So it's recommended that you move/rename or delete the following:
  
 
  # mv /etc/X11/xorg.conf /etc/X11/xorg.conf.bak
 
  # mv /etc/X11/xorg.conf /etc/X11/xorg.conf.bak
Line 123: Line 132:
  
 
  # mkinitcpio -p linux
 
  # mkinitcpio -p linux
 +
# poweroff
 +
 +
Finally, pull out the LiveCD (the ISO file) and start the virtual machine.
 +
 +
{{Note|At this point you may notice that you no longer have a wallpaper. Don't worry about it. It's most likely because it is located on a different partition mounted in {{ic|/media}} or {{ic|/mnt}}, folders which were excluded from the transfer.}}
 +
 +
Enjoy your new virtual environment.
  
 
== Troubleshoot ==
 
== Troubleshoot ==
Line 144: Line 160:
 
  # mount -o offset=$(('''2048''' * 512)) /dev/loop5 /mnt/Virtual/
 
  # mount -o offset=$(('''2048''' * 512)) /dev/loop5 /mnt/Virtual/
  
=== "Missing operating system. FATAL: INT18: BOOT FAILURE" ===
+
=== "Waiting 10 seconds for device /dev/sda1; ERROR: Unable to find root device '/dev/sda1'" ===
 
+
You will need to install (reinstall) a bootloader. See the [[Beginners'_Guide#Install_and_configure_a_bootloader|instructions]] from the Beginners' Guide.
+
 
+
=== "Waiting 10 seconds for device; ERROR: Unable to find root device" ===
+
  
 
  Waiting 10 seconds for device [...] ...
 
  Waiting 10 seconds for device [...] ...
Line 157: Line 169:
 
  [rootfs /]# _
 
  [rootfs /]# _
  
You need to regenerate your initramfs image, because the hardware has changed. To do that, you can start the VM using the Fallback entry. If you don't have a Fallback entry, press {{Keypress|Tab}} (for Syslinux) or {{Keypress|e}} (for GRUB) and rename it {{ic|initramfs-linux-fallback.img}}. After it boots, run:
+
It most likely means that you didn't run {{ic|poweroff}} like ''you were instructed to'', and closed the VM with the "close" button, which is the equivalent of a power outage. Now you need to regenerate your initramfs image. To do that, you can start the VM using the Fallback entry. If you don't have a Fallback entry, press {{Keypress|Tab}} (for Syslinux) or {{Keypress|e}} (for GRUB) and rename it {{ic|initramfs-linux-fallback.img}}.
 +
 
 +
After it boots, open up a terminal and run:
  
 
  # mkinitcpio -p linux
 
  # mkinitcpio -p linux
 +
# poweroff
 +
 +
=== "Missing operating system. FATAL: INT18: BOOT FAILURE" ===
 +
 +
You will need to install (reinstall) a bootloader. See the [[Beginners'_Guide#Install_and_configure_a_bootloader|instructions]] from the Beginners' Guide.
  
 
=== I'm asked for the root password, for maintenance ===
 
=== I'm asked for the root password, for maintenance ===

Revision as of 14:37, 27 September 2012

Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki Template:Article summary wiki Template:Article summary wiki Template:Article summary wiki Template:Article summary end

This article describes how to transfer your current Arch Linux installation in or out of a virtual environment (i.e. QEMU, VirtualBox, VMware), and is heavily based on the Full System Backup with rsync article. A virtual machine ("VM", for short) uses different hardware, which needs to be addressed by re-generating the initramfs image. While any Linux filesystem should work, it's recommended that you go with ext4, at least at first, until you get the hang of it.

Moving out of a VM

Moving out of a virtual environment is relatively easy.

Set up a shared folder

This part is specific to each program, so please visit their wiki page.

If you don't already have an ext4 partition, see Prepare the storage drive from the Beginners' Guide.

If you're on Windows, install Ext2Fsd to be able to mount it.

Transfer the system

From the virtual machine, open a terminal and transfer the system:

# rsync -aAXv /* /path/to/shared/folder --exclude={/dev/*,/proc/*,/sys/*,/tmp/*,/run/*,/mnt/*,/media/*,/lost+found,/home/*/.gvfs}

Chroot and reinstall the bootloader

Boot a "live" Linux distribution, mount the root partition and chroot into it:

# mount /dev/sdb2 /mnt
# arch-chroot /mnt

Reinstall either Syslinux or GRUB, using the instructions from the Beginners' Guide. Don't forget to update the configuration file (i.e. syslinux.cfg or grub.cfg).

Adjust the fstab

Since your entire root tree has been transferred to a single partition, edit the fstab file to reflect the right partition. Check with blkid (since lsblk is not very useful inside a chroot).

Re-generate the initramfs image

Because the hardware has changed, while you're still in the chroot, re-generate the initramfs image:

# mkinitcpio -p linux 
# poweroff

And that's about it.

You'll most likely need to set up the network, since the virtual machine was probably piggybacking on the host OS's network settings. See Configure the network from the Beginners' Guide.

Moving into a VM

Moving into a virtual environment takes a little more effort.

Create the container

This will create a 10 GB raw image:

# dd if=/dev/zero of=/media/Backup/backup.img bs=1024 count=10482381

If you want to create one the exact size of your root partition, run fdisk -l and use the value from the Blocks column. Note that you will transfer you entire root tree, so that includes the /boot and /home folders. If you have any separate partitions for those, you need to take them into account when creating the container.

Now load the necessary module and mount it as a loopback device, on /dev/loop5 (for example):

# modprobe loop
# losetup /dev/loop5 /media/Backup/backup.img

Install gparted and slap a partition table on it (e.g. "msdos") and a filesystem (e.g. "ext4"):

# pacman -S gparted
# gparted /dev/loop5
Tip: If you want, you can add however many partitions you want: home, boot, var, tmp, whatever floats your boat. Of course, it will add a layer of complexity, but it's doable. The point is that you don't necessarily need another container.

Transfer the system

Mount the loopback device and transfer the system:

Note: If the container was saved somewhere other than /mnt or /media, don't forget to add it to the exclude list.
# mkdir /mnt/Virtual
# mount /dev/loop5p1 /mnt/Virtual
# rsync -aAXv /* /mnt/Virtual --exclude={/dev/*,/proc/*,/sys/*,/tmp/*,/run/*,/mnt/*,/media/*,/lost+found,/home/*/.gvfs}

Sit back, this could take a while.

Convert the container to a compatible format

Change directory to where the loopback file is located and choose the appropriate command for your virtual machine:

$ cd /media/Backup
$ qemu-img convert -c -f raw -O qcow backup.img backup.qcow2
$ VBoxManage convertfromraw --format VDI backup.img backup.vdi
$ VBoxManage convertfromraw --format VMDK backup.img backup.vmdk

Chroot and reinstall the bootloader

Hook up the converted file from above, and the latest Arch Linux ISO into the virtual CD-ROM. Then start the virtual machine and chroot into it:

# mount /dev/sda1 /mnt
# arch-chroot /mnt

Reinstall either Syslinux or GRUB, using the instructions from the Beginners' Guide. Just don't forget to update its configuration file:

  • For Syslinux, it should be APPEND root=/dev/sda1 ro in syslinux.cfg.
  • For GRUB, it's recommended that you automatically re-generate a grub.cfg.

Adjust the fstab

Since your entire root tree has been transferred to a single partition, edit the fstab file to look like this:

# nano /etc/fstab
tmpfs                  /tmp          tmpfs     nodev,nosuid          0      0
/dev/sda1              /             ext4      defaults,noatime      0      1

Disable any Xorg-related files

Having an nvidia entry (or nouveau, radeon, intel, etc) in the Device section from one of the Xorg configuration files will inhibit the startx command, since you will be using emulated hardware (including the video card). So it's recommended that you move/rename or delete the following:

# mv /etc/X11/xorg.conf /etc/X11/xorg.conf.bak
# mv /etc/X11/xorg.conf.d/10-monitor /etc/X11/xorg.conf.d/10-monitor.bak

Re-generate the initramfs image

Because the hardware has changed, while you're still in the chroot, re-generate the initramfs image:

# mkinitcpio -p linux
# poweroff

Finally, pull out the LiveCD (the ISO file) and start the virtual machine.

Note: At this point you may notice that you no longer have a wallpaper. Don't worry about it. It's most likely because it is located on a different partition mounted in /media or /mnt, folders which were excluded from the transfer.

Enjoy your new virtual environment.

Troubleshoot

"mount: special device /dev/loop5p1 does not exist"

Check with fdisk for the starting block and use it as an offset:

# fdisk -l /dev/loop5
Disk /dev/loop5: 10.7 GB, 10733958144 bytes
255 heads, 63 sectors/track, 1304 cylinders, total 20964762 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000b45e8

      Device Boot      Start         End      Blocks   Id  System
/dev/loop5p1   *        2048    20963327    10480640   83  Linux
# mount -o offset=$((2048 * 512)) /dev/loop5 /mnt/Virtual/

"Waiting 10 seconds for device /dev/sda1; ERROR: Unable to find root device '/dev/sda1'"

Waiting 10 seconds for device [...] ...
ERROR: Unable to find root device '[...]'.
You are being dropped to a recovery shell
    Type 'exit' to try and continue booting
sh: can't access tty; job control turned off
[rootfs /]# _

It most likely means that you didn't run poweroff like you were instructed to, and closed the VM with the "close" button, which is the equivalent of a power outage. Now you need to regenerate your initramfs image. To do that, you can start the VM using the Fallback entry. If you don't have a Fallback entry, press Template:Keypress (for Syslinux) or Template:Keypress (for GRUB) and rename it initramfs-linux-fallback.img.

After it boots, open up a terminal and run:

# mkinitcpio -p linux
# poweroff

"Missing operating system. FATAL: INT18: BOOT FAILURE"

You will need to install (reinstall) a bootloader. See the instructions from the Beginners' Guide.

I'm asked for the root password, for maintenance

:: Checking Filesystems                [BUSY]
fsck.ext4: Unable to resolve '...'

This means that you forgot to add the drive's UUID, label or device name in /etc/fstab. The UUID is different every time you format it (or in this case, create one from scratch), and they likely do not match. Check with blkid.