Re: [CentOS] Create CentOS 6 system as "clone" of another - with LVM and different disk sizes

2018-04-13 Thread m . roth
Toralf Lund wrote:
> Hi,
>
> I just found myself having to set up a new CentOS 6 system with a nearly
> identical configuration to an existing host, so I thought I would just
>
>  1. Do a minimal install to set up partitions etc. on the new system.
>  2. Create an image of the existing system using Clonezilla
> (http://www.clonezilla.org)
>  3. Run a Clonezilla restore on the new system.
>
> - as I though it would be a lot simpler than replicating the exact
> package selection, installing the same users, doing the same manual
> config edits (which are required) etc.
>
> It turns out that it wasn't quite as easy, though. The problem is that
> the system use LVM2 volumes for the filesystems, and the new host has a
> slightly smaller disk than the other, and Clonezilla seems unable to
> restore to a volume that's smaller than the one that was cloned - even
> if the actual data fits.
>
> I guess I could temporarily reduce the LVM volume sizes on the existing
> units and clone again, but I'd rather not if I can avoid it. Just
> copying file-by-file could be an option, too, but I somehow feel less
> comfortable doing that than the above; there is something about the way
> I could end up with a mixture of my "minimal install" and the "cloned"
> data, I suppose.
>
> Does anyone have any other ideas about how I might achieve what I want?

Manually clone it.

On the new machine:
mkdir /new
mkdir /boot/new
rsync -HPavzx --exclude=/old --exclude=/var/log/wtmp $machine:/. /new/.
rsync -HPavzx $machine:/boot/. /boot/new/.

where $machine is the system you're cloning from. You might want to
exclude other logfiles.

To prevent problems with the Ethernet interfaces:

rsync -HPavzx /etc/sysconfig/network-scripts/ifcfg-eth*
/new/etc/sysconfig/network-scripts
rsync -HPavzx /etc/sysconfig/hwconf /new/etc/sysconfig
rsync -HPavzx /boot/grub/device.map /boot/new/grub/
rsync -HPavzx /etc/udev/rules.d/70-persistent-net.rules
/new/etc/udev/rules.d/

Clean log files - you don't really want any of the old systems:

find /new/var/log/ -type f -exec cp /dev/null {} \;

Copy the original SSH keys - you do *not* want the keys of the system
you're cloning from:

rsync -HPavzx /etc/ssh/ssh_host* /new/etc/ssh

Now rotate: zsh, because it lets you load it's builtin-s, so mv works

zsh
zmodload zsh/files

cd /boot
mkdir old
mv * old
mv old/lost+found .
mv old/new/* .

# Root partition.
cd /
mkdir old
mv * old
mv old/lost+found .
#mv old/root . -- WHY?
mv old/scratch .
mv old/new/* .

sync
sync

Also you might want to

  touch /.autorelabel

to shut up selinux.

Note that this assumes the same CPU, etc, Otherwise, you might need to
make a new initrd.

  mark

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[CentOS] Create CentOS 6 system as "clone" of another - with LVM and different disk sizes

2018-04-13 Thread Toralf Lund

Hi,

I just found myself having to set up a new CentOS 6 system with a nearly 
identical configuration to an existing host, so I thought I would just


1. Do a minimal install to set up partitions etc. on the new system.
2. Create an image of the existing system using Clonezilla
   (http://www.clonezilla.org)
3. Run a Clonezilla restore on the new system.

- as I though it would be a lot simpler than replicating the exact 
package selection, installing the same users, doing the same manual 
config edits (which are required) etc.


It turns out that it wasn't quite as easy, though. The problem is that 
the system use LVM2 volumes for the filesystems, and the new host has a 
slightly smaller disk than the other, and Clonezilla seems unable to 
restore to a volume that's smaller than the one that was cloned - even 
if the actual data fits.


I guess I could temporarily reduce the LVM volume sizes on the existing 
units and clone again, but I'd rather not if I can avoid it. Just 
copying file-by-file could be an option, too, but I somehow feel less 
comfortable doing that than the above; there is something about the way 
I could end up with a mixture of my "minimal install" and the "cloned" 
data, I suppose.


Does anyone have any other ideas about how I might achieve what I want?

- Toralf

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