How to set DNS on Ubuntu 12.04 clients?

[Sandra Schlichting]

Hi all =)

Does anyone know of a module that can configure the DNS on Ubuntu 12.04 clients?

This module works for CentOS and Ubuntu < 12.04

http://forge.puppetlabs.com/saz/resolv_conf

but in Ubuntu 12.04 you can't just overwrite the /etc/resolv.conf anymore. DNS have to be set in /etc/network/interfaces

Does anyone know how to do this in puppet?

Hugs,

Sandra =)

[Andreas Ntaflos]

On 11/09/12 16:00, Sandra Schlichting wrote:
> Hi all =)
>
> Does anyone know of a module that can configure the DNS on Ubuntu 12.04
> clients?
>
> This module works for CentOS and Ubuntu < 12.04
>
> http://forge.puppetlabs.com/saz/resolv_conf
>
> but in Ubuntu 12.04 you can't just overwrite the /etc/resolv.conf
> anymore. DNS have to be set in /etc/network/interfaces

Not necessarily. I have not tried this myself yet, but you can put
static DNS settings in /etc/resolvconf/resolv.conf.d/{head,base,tail}.
Afterwards call "service resolvconf restart". See here for details:
http://www.stgraber.org/2012/02/24/dns-in-ubuntu-12-04/

You should be able to adapt the resolv_conf module accordingly, or write
your own.

Andreas

[Stephen Gran]

Hi,

Surely if you're statically configuring DNS on a server, you don't want
a dynamic DNS configuration daemon running on the same server.

Presumably something like:

package { 'resolvconf':
ensure => purged
}

And then get on with your life?

Cheers,
--
Stephen Gran
Senior Systems Integrator - guardian.co.uk

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[Sandra Schlichting]

Surely if you're statically configuring DNS on a server, you don't want
a dynamic DNS configuration daemon running on the same server.

Presumably something like:

package { 'resolvconf':
        ensure => purged
}

And then get on with your life?

That is a very attractive solution fore sure!

Should I just ignore that it depends on the "ubuntu-minimal" package?

[Joe Topjian]

That is a very attractive solution fore sure!

Should I just ignore that it depends on the "ubuntu-minimal" package?

ouch. 

Since /etc/resolv.conf is a symlink to resolvconf's resolv.conf, you can break the symlink, turn resolv.conf into a normal static file and then use the puppet module.

I am not 100% confident of this solution, though, since I'm not sure if resolvconf will recreate the symlink at some point -- I haven't used this solution enough to confirm that.

Thanks,

Joe

--
Joe Topjian

Systems Administrator

Cybera Inc.

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[Stephen Gran]

Hi,

It won't cause any harm (as in, lack of functionality) - the
ubuntu-minimal package only exists to make sure other software is
installed. If you are uneasy about removing the package, you can also
presumably just make sure the service doesn't run.

[Craig White]

On Sep 11, 2012, at 8:54 AM, Joe Topjian wrote:

> That is a very attractive solution fore sure!
>
> Should I just ignore that it depends on the "ubuntu-minimal" package?
>
> ouch.
>
> Since /etc/resolv.conf is a symlink to resolvconf's resolv.conf, you can break the symlink, turn resolv.conf into a normal static file and then use the puppet module.
>
> I am not 100% confident of this solution, though, since I'm not sure if resolvconf will recreate the symlink at some point -- I haven't used this solution enough to confirm that.

----
if /etc/resolv.conf is a puppet maintained file, even if resolvconf package is updated, it will be replaced by the puppet asserted file anyway.

Craig

[Sandra Schlichting]

Not necessarily. I have not tried this myself yet, but you can put
static DNS settings in /etc/resolvconf/resolv.conf.d/{head,base,tail}.
Afterwards call "service resolvconf restart". See here for details:
http://www.stgraber.org/2012/02/24/dns-in-ubuntu-12-04/

Just tried it, and just treating /etc/resolvconf/resolv.conf.d/base as your /etc/resolv.conf works.

 

You should be able to adapt the resolv_conf module accordingly, or write
your own.

That should be interesting. I on it =)

 

[Joe Topjian]

if /etc/resolv.conf is a puppet maintained file, even if resolvconf package is updated, it will be replaced by the puppet asserted file anyway.

Very true, but I would hate to have two services fighting with each other in that way. 

[Craig White]

On Sep 11, 2012, at 10:08 AM, Joe Topjian wrote:

> if /etc/resolv.conf is a puppet maintained file, even if resolvconf package is updated, it will be replaced by the puppet asserted file anyway.
>
> Very true, but I would hate to have two services fighting with each other in that way.

----
well, I upgraded a 10.04 test server to 12.04 and noticed the messaging about the dynamic nature of /etc/resolv.conf in the Ubuntu server list but it hasn't been a problem at all so I have left it alone (with puppet fully managing /etc/resolv.conf). There's been no contention so I gather that if /etc/resolv.conf isn't a symlink, it isn't mucked with by the Ubuntu/Debian packaging.

I am however starting to gear up for testing puppet 3, on a test server and ruby 1.93 clients with puppet 3 and even though the current estimate is another year of 10.04 for new deploys, I have an eye on this issue but so far, it's not been a problem.

Craig