Puppet users - Mar 2012 - multi-line key/value pairs in Puppet Dashboard?

We''d like to control, among other files, /etc/sysctl.conf with Puppet.
We have a baseline for this file on all our servers, but frequently
some of our applications require additional tweaks. These tweaks are
generally more than a single line.

I know that we could create a class in our module repository with the
necessary additions, then define that class inside Dashboard and apply
it to hosts as needed. That seems a little inflexible, as we''d need to
create a class for each app, and define inside that class the changes
that we need.

I''d prefer a more extensible solution that abstracts this a bit. A
"sysctl-additions" class, for example, that relies upon a
Dashboard-defined variable that contains the additions to place into
the file. But how can I (easily?) add multiple lines to the Dashboard
variable? Or do I have to create multiple key/value pairs for each
line I wish to add?

When using Puppet Dashboard, how does one easily add multiple lines to
a Puppet-controlled file? Or should we not be using Dashboard for
that?

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On Mon, Mar 19, 2012 at 3:12 PM, Scott Merrill <skippy@skippy.net> wrote:
> We''d like to control, among other files, /etc/sysctl.conf with
Puppet.
> We have a baseline for this file on all our servers, but frequently
> some of our applications require additional tweaks. These tweaks are
> generally more than a single line.
>
Scott,

The traditional way to solve this problem is with the file fragement
pattern, which would use a defined resource type to manage small file
fragments of a line or two each.  An additional resource would be related
to all of these fragment resources and would then concatenate them together
into the final sysctl file.

I notice the only sysctl puppet module that''s published to the Forge
[1]
doesn''t employ the file fragment pattern, but instead manages the file
in
it''s entirety.

> I know that we could create a class in our module repository with the
> necessary additions, then define that class inside Dashboard and apply
> it to hosts as needed. That seems a little inflexible, as we''d
need to
> create a class for each app, and define inside that class the changes
> that we need.
>
If you''d like to use the Dashboard to add new entries, then I may not
employ the file fragment pattern.

This is actually a pretty big shortcoming of the current Dashboard. 
It''s
difficult to have an arbitrary number of resources (sysctl entries in your
case) added to the catalog based on information in the Dashboard.

Today, you can accomplish this by either splitting a comma separated
string, or pasting a YAML or JSON hash into the dashboard wholesale and
using the create_resources() function with the resulting Puppet variable as
input..

> I''d prefer a more extensible solution that abstracts this a bit. A
> "sysctl-additions" class, for example, that relies upon a
> Dashboard-defined variable that contains the additions to place into
> the file. But how can I (easily?) add multiple lines to the Dashboard
> variable? Or do I have to create multiple key/value pairs for each
> line I wish to add?
>
You can definitely do this today, but it''s far from ideal.  If
you''d like
some examples or have more questions about the high level overview I
described above I''d be happy to work with you more on this problem.

When using Puppet Dashboard, how does one easily add multiple lines
to
> a Puppet-controlled file? Or should we not be using Dashboard for
> that?
>
I''d really only use the Dashboard if I had to make the UI available
through
a browser.  If you can get away with it, data in a YAML or JSON file on
disk or in something like extlookup() or hiera() may be a better fit with
Puppet today.

[1] http://forge.puppetlabs.com/ghoneycutt/sysctl

Hope this helps,
-Jeff McCune

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I can''t help with your Dashboard problems, but can suggest an 
alternative to file fragments that you might find easier to work with. I 
would use a Defined Type wrapped around Augeas where the $namevar of the 
Defined Type is the name of the systctl.conf key. This way if you tried 
to turn ipv6 on and off at the same time you''d get a Puppet resource 
conflict.

Something like this:

define syssctl_line($value) {
   $sysconfig_file = "/etc/sysctl.conf"
   augeas { "set ${name} in ${sysconfig_file}":
     context => "/files${sysconfig_file}",
     incl    => "$sysconfig_file",
     lens    => "shellvars.lns",
     changes => [ "set ${name} ${value}"]
   }
}

And used like this:

class foo {
   sysctl_line { "net.ipv4.ip_forward": value => "0" }
   sysctl_line { "kernel.sysrq": value => "0" }
   #And this would cause an error on a node...
   sysctl_line { "net.ipv4.ip_forward": value => "1" }
}

On 19/03/12 19:12, Scott Merrill wrote:
> We''d like to control, among other files, /etc/sysctl.conf with
Puppet.
> We have a baseline for this file on all our servers, but frequently
> some of our applications require additional tweaks. These tweaks are
> generally more than a single line.
>
> I know that we could create a class in our module repository with the
> necessary additions, then define that class inside Dashboard and apply
> it to hosts as needed. That seems a little inflexible, as we''d
need to
> create a class for each app, and define inside that class the changes
> that we need.
>
> I''d prefer a more extensible solution that abstracts this a bit. A
> "sysctl-additions" class, for example, that relies upon a
> Dashboard-defined variable that contains the additions to place into
> the file. But how can I (easily?) add multiple lines to the Dashboard
> variable? Or do I have to create multiple key/value pairs for each
> line I wish to add?
>
> When using Puppet Dashboard, how does one easily add multiple lines to
> a Puppet-controlled file? Or should we not be using Dashboard for
> that?
>

-- 
Luke Bigum

Information Systems
Ph: +44 (0) 20 3192 2520
luke.bigum@lmax.com | http://www.lmax.com
LMAX, Yellow Building, 1A Nicholas Road, London W11 4AN


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Thanks, Jeff and Luke, for the replies!

After reviewing Luke''s suggestion and thinking things through a little
more, I think this is the right way to go for us. I hadn''t really
considered the long-term ramifications of putting configuration
declarations in both Puppet manifests and in Dashboard. Much better to
keep all configurations in manifests under version control, and use
Dashboard to associate configurations to nodes.

Cheers,
Scott

On Tue, Mar 20, 2012 at 4:37 AM, Luke Bigum <Luke.Bigum@lmax.com>
wrote:
> I can''t help with your Dashboard problems, but can suggest an
alternative to
> file fragments that you might find easier to work with. I would use a
> Defined Type wrapped around Augeas where the $namevar of the Defined Type
is
> the name of the systctl.conf key. This way if you tried to turn ipv6 on and
> off at the same time you''d get a Puppet resource conflict.
>
> Something like this:
>
> define syssctl_line($value) {
>  $sysconfig_file = "/etc/sysctl.conf"
>  augeas { "set ${name} in ${sysconfig_file}":
>    context => "/files${sysconfig_file}",
>    incl    => "$sysconfig_file",
>    lens    => "shellvars.lns",
>    changes => [ "set ${name} ${value}"]
>  }
> }
>
> And used like this:
>
> class foo {
>  sysctl_line { "net.ipv4.ip_forward": value => "0" }
>  sysctl_line { "kernel.sysrq": value => "0" }
>  #And this would cause an error on a node...
>  sysctl_line { "net.ipv4.ip_forward": value => "1" }
>
> }
>
> On 19/03/12 19:12, Scott Merrill wrote:
>>
>> We''d like to control, among other files, /etc/sysctl.conf with
Puppet.
>> We have a baseline for this file on all our servers, but frequently
>> some of our applications require additional tweaks. These tweaks are
>> generally more than a single line.
>>
>> I know that we could create a class in our module repository with the
>> necessary additions, then define that class inside Dashboard and apply
>> it to hosts as needed. That seems a little inflexible, as we''d
need to
>> create a class for each app, and define inside that class the changes
>> that we need.
>>
>> I''d prefer a more extensible solution that abstracts this a
bit. A
>> "sysctl-additions" class, for example, that relies upon a
>> Dashboard-defined variable that contains the additions to place into
>> the file. But how can I (easily?) add multiple lines to the Dashboard
>> variable? Or do I have to create multiple key/value pairs for each
>> line I wish to add?
>>
>> When using Puppet Dashboard, how does one easily add multiple lines to
>> a Puppet-controlled file? Or should we not be using Dashboard for
>> that?
>>
>
>
> --
> Luke Bigum
>
> Information Systems
> Ph: +44 (0) 20 3192 2520
> luke.bigum@lmax.com | http://www.lmax.com
> LMAX, Yellow Building, 1A Nicholas Road, London W11 4AN
>
>
> The information in this e-mail and any attachment is confidential and is
> intended only for the named recipient(s). The e-mail may not be disclosed
or
> used by any person other than the addressee, nor may it be copied in any
> way. If you are not a named recipient please notify the sender immediately
> and delete any copies of this message. Any unauthorized copying, disclosure
> or distribution of the material in this e-mail is strictly forbidden. Any
> view or opinions presented are solely those of the author and do not
> necessarily represent those of the company.
>
>
> --
> You received this message because you are subscribed to the Google Groups
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