Cloning Servers

[columb]

OK, so her's the problem. We have a number of servers each built on identical hardware but with slightly different modules etc. For administrative reasons we want them to be totally identical from a Linux perspective. The plan is
[ol]
[li]Build a server to standard RedHat ES4 with all the bits we want (and not those we don't)[/li]
[li]Backup this server using mondoarchive[/li]
[li]On each of the production servers
[ol]
[li]Put a USB Memory stick in the front[/li]
[li]tar up a list of files to this memory stick[/li]
[li]Restore the image built on the test server onto the live chasis[/li]
[li]untar the files back off the memory stick[/li]
[li]reboot and there you are[/li]
[/ol][/li]
[/ol]

The BIG question is exactly which files need to be tarred up. My list so far is

/etc/hosts
/etc/passwd
/etc/shadow
/etc/group
/etc/cron*
/etc/*.allow
/etc/*.deny

/etc/ssh/*
/etc/sysconfig/*

/home/*

There is another school of thought (my favourite) that it would be best to backup all of /etc except one or two files but no-one can decide which.


So the questions are
[ol]
[li]Should we be trying this at all?[/li]
[li]If so how do we define the file list to back up[/li]
[li]Should our approach be backup all of /etc except selected files or backup selected files.[/li]
[/ol]

An ideas/input gratefully received

Columb Healy

 

[BocaBurger]

Why not just tar up the whole drive and put it on the cloned servers?

We did this years ago as part of a Y2K plan. We also used tar to clone Windows machines (no $ for Ghost or other commercial program).

We had the image on a server and booted from a small Slackware image on floppy to get the machine onto the network.

We imaged about 25 machines in a few hours.



BocaBurger
<===========================||////////////////|0
The pen is mightier than the sword, but the sword hurts more!

 

[columb]

Sorry - I didn't make myself clear. The problem is not the cloning process per se, it's identifying the files whcih give a server its personality.

The background is that we have a number of servers which were built in a rush for a project. Whereas they ought to be an identical controlled build there are a number of small differences. For a number of reasons we want to standardise the build. I therefore want to replace an existing build with a clone whilst keeping all the bits that make it the server is is. I have no problem with the software it's running, that has clearly defined configuration files and I can back them up and copy them back again. It's linux itself which is causing headaches. For example I know I do want to keep all the inet config files as these are very much part of the individual server. However I do not want to keep the rpm database as that will have changed when the uncontrolled build is replaced by the clone.

Part of me says that the only thing in /etc which I need are the config files, part of me wants to copy back all of /etc except the rpm database (which is not in /etc anyway). Any advice?

Columb Healy

 

[Annihilannic]

Personally I would prefer to select the files that I transferred so that I knew exactly what I had changed, rather than doing "everything except x, y and z".

Annihilannic.

 

[columb]

Answered my own question

I tarred up /etc on server A, copied it across to Server B and untarred it in /tmp/etc Then

cd /tmp/etc
for i in $(find . -type d)
do
  diff --brief $i /etc/$i | grep -v "Common subdirectories"
done > /tmp/different_files

The list of files in /tmp/different_files needs editing and some of it can be done by directory rather than file but it makes sure nothing is missed.

Columb Healy