[rear-users] Creating a Master Image

Jeremy Laidman jlaidman at rebel-it.com.au
Wed Apr 22 04:39:57 CEST 2015


(Hint: use "blkid" to find the current block IDs for filesystems, pvdisplay
for PVs, and vgdisplay for VGs)

It'd be really neat to have an option "rear mkmaster" that stripped out or
reset those types of host-specific identifiers such as UUIDs and MAC
addresses.  A filesystem or PV probably requires a UUID of some sort, but
perhaps it can be forced to be a special UUID (eg
"0ReAR0-ReAR-ReAR-ReAR-ReAR-ReAR-0ReAR0") that can be recognised by "rear
recover".

It'd also be neat to have an option "rear uniquify" that re-generates
filesystem LVM device UUIDs, and performs fix-ups for files containing
these, and MAC addresses.

J


On 22 April 2015 at 12:21, Jeremy Laidman <jlaidman at rebel-it.com.au> wrote:

> John
>
> I've done exactly this, for RHEL6 - sort of a poor-man's "Ghost" for
> linux.  There are several things you need to do to make the servers
> unique.  For example, it might not be a good thing that different servers
> have the same LVM UUIDs or you might accidentally restore a backup to the
> wrong server; also the mappings from MAC address to ethernet device won't
> match and you'll be using eth5 instead of eth0 as your first NIC.
>
> A POST_RECOVERY_SCRIPT is a great idea.  We didn't do it this time, but
> next time I'll look into it.
>
> Here's a list of things we had to fix up on each server:
>
> * MAC-to-eth mappings:
>   - remove /etc/udev/rules.d/70-persistent-net.rules
>   - removed HWADDR and UUID from /etc/sysconfig/network-scripts/ifcfg-eth*
>   - reboot
>
> * Filesystem UUIDs:
>   - tune2fs -U `uuidgen` $FS
>   - rebuilt swap filesystem: swapoff $SWAPFS && mkswap $SWAPFS & swapon
> $SWAPFS
>   - updated UUIDs referenced in /etc/fstab
>   - reboot
>
> * LVM VG UUID:
>   - boot into single-user mode
>   - run "pvdisplay" to get device names
>   - pvchange -u /dev/<devicename>
>
> Cheers
> Jeremy
>
>
> On 3 April 2015 at 02:15, John Wade <John.Wade at comdev.ca> wrote:
>
>>  Is there a way to create a “Master image” of a server and deploy it
>> with a different hostname and static IP address using ReaR?
>>
>>
>>
>> I have Red Hat 6 server that was set up using a third party engineering
>> app (cannot be installed via rpm or yum, must be installed manually), and
>> now that I have it working successfully, would like to use it as a template
>> for 8 others servers, the only items that are different are the hostname
>> and the IP address (static).
>>
>>
>>
>> Is there a way to do this using ReaR ?
>>
>>
>>
>> Thanks in advance,
>>
>> John
>>
>> _______________________________________________
>> rear-users mailing list
>> rear-users at lists.relax-and-recover.org
>> http://pikachu.3ti.be/mailman/listinfo/rear-users
>>
>>
>
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