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 %>
Thank you for the excellent example! There are several things here that I'm going to have to ponder for a while. I've seen scope.lookupvar before but never personally had to use it, but the scope.function_<functionname> is new to me. Time to do some more reading and research, but what you've provided really helps point me in the right direction. Tim
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 58105-5164On 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
-- 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 -- You received this message because you are subscribed to the Google Groups "Puppet Users" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/puppet-users?hl=en.
