[drbd-mc] debian-style config with dmc

[Peter Beck]

Hi guys,

I am using Debian (Squeeze) and I've just downloaded DMC 0.8.6.
The DRBD config files on Debian are stored in /etc/drbd.d/
and the /etc/drbd.conf just links to this directory:

drbd.conf:----8<--------8<--------
include "drbd.d/global_common.conf";
include "drbd.d/*.res";
----8<--------8<--------8<--------

DMC will replace this config with its own config including all
resources. Will this change to work with "debian-style" in future
releases ?

This is not a "real" problem (i think on most systems it's this way, but
not debian), I just want to know if I have to use this "style" of config
in future or if it will work with "debian-default" ;)

Other than that - I love this app, great work, makes live much easier
(for me as cluster-newbie)

Regards
Peter

[Jerry Amundson]

Post by Peter Beck
Hi guys,

Hello.

Post by Peter Beck
I am using Debian (Squeeze) and I've just downloaded DMC 0.8.6.
The DRBD config files on Debian are stored in /etc/drbd.d/
drbd.conf:----8<--------8<--------
include "drbd.d/global_common.conf";
include "drbd.d/*.res";
----8<--------8<--------8<--------
DMC will replace this config with its own config including all
resources. Will this change to work with "debian-style" in future
releases ?

This "style" is also in effect with Fedora, so I suspect upstream
source is creating the layout as such.

Post by Peter Beck
This is not a "real" problem (i think on most systems it's this way, but
not debian), I just want to know if I have to use this "style" of config
in future or if it will work with "debian-default" ;)

Me too. I prefer to not overwrite modular, flexible files placed by
smart packages. :)

Post by Peter Beck
Other than that - I love this app, great work, makes live much easier

Me too.

jerry

[Rasto Levrinc]

Post by Jerry Amundson

Post by Peter Beck
DMC will replace this config with its own config including all
resources. Will this change to work with "debian-style" in future
releases ?

This "style" is also in effect with Fedora, so I suspect upstream
source is creating the layout as such.

That's right. It's a nice feature but unfortunately they made it as a
default example config.

Rasto

[Rasto Levrinc]

Post by Peter Beck
Hi guys,
I am using Debian (Squeeze) and I've just downloaded DMC 0.8.6.
The DRBD config files on Debian are stored in /etc/drbd.d/
drbd.conf:----8<--------8<--------
include "drbd.d/global_common.conf"; include "drbd.d/*.res";
----8<--------8<--------8<--------
DMC will replace this config with its own config including all
resources. Will this change to work with "debian-style" in future releases
?

It works with "debian-style" configs. It was actually introduced in DRBD
couple of months ago. As you will see later, this not as big problem as it
seems, but it can create an endless confusion. It is a known problem.

Here's what happens: drbdadm parses the config and creates an XML, that
GUI like DRBD MC can use. In this XML all the DRBD config is present, but
the on-disk layout of config files is lost. As you save the config in the
GUI. the small drbd.conf with include directives is overwritten with a big
config with all the resources without the include directives.

So nothing is lost, only there are files laying around that are not
included and an admins that write configs by hand may not notice it and
modify not used config files, etc.

There are couple of solutions to this, but none of them is good:

1. DRBD MC can parse the config from disk, instead of getting XML config
from drbdadm. To reimplement the parser in the GUI would be very
impractical and another moving target, that should be avoided if possible.

2. Leave it like it is. It works, but it can hit some people, like it did
hit you.

3. DRBD MC can create a modular layout by default, with a file per
resource and small drbd.conf with include directives, but that could again
leave some unincluded files laying around and create an endless confusion.
It also creates problems with DRBD config backup.

I am tending to the 3. option, but if somebody has 4., I am all ears. :)

Rasto

[Peter Beck]

On Thu, 2010-12-30 at 08:17 +0100, Rasto Levrinc wrote:

Hi Rasto,

[...] this not as big problem as it seems, but it can create an
endless confusion. It is a known problem.

This is why I wrote the mail. on my system just one of three resources
were imported into the new config and I was confused why the other two
resources refused to work after rebooting the system...

2. Leave it like it is. It works, but it can hit some people, like it
did hit you.

I can live with this situation, it's not a big deal. Maybe a warning
message in the GUI before replacing the original file would be
appropriate ?

3. DRBD MC can create a modular layout by default, with a file per
resource and small drbd.conf with include directives, but that could
again leave some unincluded files laying around and create an endless
confusion. It also creates problems with DRBD config backup.

I can understand that it's not easy to satisfy every situation and
little things like the different config can cause a lot of programming
effort for no additional benefit. Personally I prefer one file per
resource, but hey, we get a really *great* tool to manage clusters with
DMC and I really appreciate your work...if this is the way to go, I will
accept that decision.

Best Regards & a happy new year... :)
Peter