[Puppet Users] how to resolve hostnames to IP addresses in templates

On Thursday, August 9, 2012 4:18:17 PM UTC-5, Wolf Noble wrote:
if you're using hiera, why not something like:


foo_data_webfarm_http_servers:
foo1.example.com: {
ip: '1.2.3.4',
port: '80',
}

In regard to: Re: [Puppet Users] how to resolve hostnames to IP addresses...:

if you're using hiera, why not something like:

foo_data_webfarm_http_servers:
foo1.example.com: {
ip: '1.2.3.4',
port: '80',
}
foo2.example.com: {
ip: '2.3.4.5',
port: '80',
}
foo_data_webfarm_https_servers:
foo1.example.com: {
ip: '1.2.3.4',
port: '443',
}
foo2.example.com: {
ip: '2.3.4.5',
port: '443',
}

class foo::data {
include foo::params
file { 'foo.conf':
path => '/etc/foo.conf',
ensure => 'file',
content => template(foo_conf.erb),
mode => '0555',
}

class foo::params {
$webfarm_http_servers = hiera('foo_data_webfarm_http_servers', '')
$webfarm_https_servers = hiera('foo_data_webfarm_https_servers', '')
}


foo_conf.erb
<% http_servers = scope.lookupvar('foo::params::webfarm_http_servers')
https_servers = scope.lookupvar('foo::params::webfarm_https_servers')
-%>
#
# http servers
<% http_servers.each_pair do |key, hash| -%>
#<%=key%>
IPADDR= <%=hash['ip'] %>
PORT= <%=hash['port'] %>
<% end%>
#
# https servers
<% https_servers.each_pair do |key, hash| -%>
#<%=key%>
IPADDR= <%=hash['ip'] %>
PORT= <%=hash['port'] %>
<% end%>

<% end%>

________________________________

This message may contain confidential or privileged information. If you are not the intended recipient, please advise us immediately and delete this message. See http://www.datapipe.com/legal/email_disclaimer/ for further information on confidentiality and the risks of non-secure electronic communication. If you cannot access these links, please notify us by reply message and we will send the contents to you.

On Aug 9, 2012, at 5:42 PM, Tim Mooney wrote:

In regard to: Re: [Puppet Users] how to resolve hostnames to IP addresses...:

I have no real knowledge of how that's going to work; I have been
namespacing things based on what I felt made things very clear for
people looking at the hiera values, and the templates.

afaik there's no significant penalty for longish names, but it makes it
a bit easier for me to ingest when looking through a gaggle of hiera
parameters.

On Thursday, August 9, 2012 1:38:14 PM UTC-7, Tim Mooney wrote:
Environment: puppet 2.7.14 on both master and all clients. We're also

using puppetlabs-stdlib and hiera, if that matters.



I know this is really more of a ruby/erb question, but I've been searching

for a couple hours and haven't turned up anything relatively close to what

I'm trying to do, and I'm hoping someone here has had to do this and can

provide a suggestion for how to proceed.



I'm generating a configuration file from a template. The configuration

file will need to have IP addresses in it, but I would like to be able to

use either hostnames or IP adresses in the puppet config. This means

that I need to be able to resolve the hostnames and turn them into IP

addresses, probably in the template itself.



Basically, given something like this in puppet:



class foo::data {



$webfarm = {

http_servers => hiera('webfarm_http_servers', [

{

host => 'foo1.example.com',

port => '80',

},

{

host => 'foo2.example.com',

port => '80',

},

{

host => 'foo3.example.com',

port => '80',

},

]),

https_servers => hiera('webfarm_https_servers', [

{

host => 'foo1.example.com',

port => '443',

},

{

host => 'foo22.example.com',

port => '443',

},

{

host => 'foo99.example.com',

port => '443',

},

]),

}

}



I need my template to iterate over the http_servers and https_servers

arrays and resolve the values for the host key for each element.



Anyone have an example of how to do this in a template?



Thanks,



Tim

--

Tim Mooney [email protected]

Enterprise Computing & Infrastructure 701-231-1076 (Voice)

Room 242-J6, IACC Building 701-231-8541 (Fax)

North Dakota State University, Fargo, ND 58105-5164
On Thursday, August 9, 2012 1:38:14 PM UTC-7, Tim Mooney wrote:
Environment: puppet 2.7.14 on both master and all clients. We're also

using puppetlabs-stdlib and hiera, if that matters.



I know this is really more of a ruby/erb question, but I've been searching

for a couple hours and haven't turned up anything relatively close to what

I'm trying to do, and I'm hoping someone here has had to do this and can

provide a suggestion for how to proceed.



I'm generating a configuration file from a template. The configuration

file will need to have IP addresses in it, but I would like to be able to

use either hostnames or IP adresses in the puppet config. This means

that I need to be able to resolve the hostnames and turn them into IP

addresses, probably in the template itself.



Basically, given something like this in puppet:



class foo::data {



$webfarm = {

http_servers => hiera('webfarm_http_servers', [

{

host => 'foo1.example.com',

port => '80',

},

{

host => 'foo2.example.com',

port => '80',

},

{

host => 'foo3.example.com',

port => '80',

},

]),

https_servers => hiera('webfarm_https_servers', [

{

host => 'foo1.example.com',

port => '443',

},

{

host => 'foo22.example.com',

port => '443',

},

{

host => 'foo99.example.com',

port => '443',

},

]),

}

}



I need my template to iterate over the http_servers and https_servers

arrays and resolve the values for the host key for each element.



Anyone have an example of how to do this in a template?



Thanks,



Tim

--

Tim Mooney [email protected]

Enterprise Computing & Infrastructure 701-231-1076 (Voice)

Room 242-J6, IACC Building 701-231-8541 (Fax)

North Dakota State University, Fargo, ND 58105-5164

In regard to: [Puppet Users] Re: how to resolve hostnames to IP addresses...:

There's no way to do DNS lookups in a template with stock Puppet,
Thanks for confirming what my futile research seemed to be implying. :-)
but you can pretty easily write a custom function to do that for you. By
default, Resolv will use the settings in /etc/resolv.conf, so as long as
your nameservers are set up correctly on the puppetmaster, you shouldn't
run into any problems.

Try plopping something like this into lib/puppet/parser/functions/get_ip_addr.rb in your module's directory:
<a href="https://gist.github.com/3308273">https://gist.github.com/3308273</a>

require 'resolv'

module Puppet::Parser::Functions
newfunction(:get_ip_addr, :type => :rvalue) do |args|
# Super sexy regex to match valid IPs
ip_addr_re = /\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b/
hostname = args[0].strip
if hostname =~ ip_addr_re then return hostname end
begin
Resolv::DNS.open { |dns| return dns.getaddress hostname }
rescue Resolv::ResolvError
return ''
end
end
end


Then you can call it in your template file as ```scope.function_get_ip_addr``` and it will either return the IP address for a hostname, the unchanged IP address for a valid IP address, and an empty string otherwise.

I'm not sure what your hiera() calls are supposed to return, but assuming $webfarm ends up as a hash with keys http_servers and https_servers containing an array of hashes with keys host and port, you could do something like this:

<% webfarm = scope.lookupvar 'foo::data::webfarm' %>
<% webfarm['http_servers'].each do |server| %>
<%= scope.function_get_ip_addr server['host'] %>:<%= server['port'] %>
<% end %>

Environment: puppet 2.7.14 on both master and all clients. We're also
using puppetlabs-stdlib and hiera, if that matters.

I know this is really more of a ruby/erb question, but I've been searching
for a couple hours and haven't turned up anything relatively close to what
I'm trying to do, and I'm hoping someone here has had to do this and can
provide a suggestion for how to proceed.

I'm generating a configuration file from a template. The configuration
file will need to have IP addresses in it, but I would like to be able to
use either hostnames or IP adresses in the puppet config. This means
that I need to be able to resolve the hostnames and turn them into IP
addresses, probably in the template itself.

Basically, given something like this in puppet:

class foo::data {

$webfarm = {
http_servers => hiera('webfarm_http_servers', [
{
host => 'foo1.example.com',
port => '80',
},
{
host => 'foo2.example.com',
port => '80',
},
{
host => 'foo3.example.com',
port => '80',
},
]),
https_servers => hiera('webfarm_https_servers', [
{
host => 'foo1.example.com',
port => '443',
},
{
host => 'foo22.example.com',
port => '443',
},
{
host => 'foo99.example.com',
port => '443',
},
]),
}
}

I need my template to iterate over the http_servers and https_servers
arrays and resolve the values for the host key for each element.

Anyone have an example of how to do this in a template?

Thanks,

Tim
--
Tim Mooney [email protected]<javascript:>
Enterprise Computing & Infrastructure 701-231-1076
(Voice)
Room 242-J6, IACC Building 701-231-8541 (Fax)
North Dakota State University, Fargo, ND 58105-5164

On Friday, June 21, 2013 at 6:29:25 PM UTC+10, Tomas wrote:

It is not so complicated as others wrote here.

Here is an example how I use it:

allowed_hosts=<% for nagios_server in nagios_servers %><% ipInt =
Socket.gethostbyname(nagios_server)[3] %><%= "%d.%d.%d.%d" % [ipInt[0],
ipInt[1], ipInt[2], ipInt[3]] %>,<% end %>



Dne čtvrtek, 9. srpna 2012 22:38:14 UTC+2 Tim Mooney napsal(a):