[chef] Re: Re: Setting up hosts between multiple boxes on EC2

["Luis Correa d'Almeida" < >]

Great, thanks. Using search works well for my setup.

On Sun, Nov 20, 2011 at 3:42 PM, Haim Ashkenazi
<
 >
 wrote:
> One more thing, In this setup the node is named with the general name
> (db.domain.com). Otherwise change the NODENAME variable.
>
> On Sun, Nov 20, 2011 at 5:40 PM, Haim Ashkenazi 
> <
 >
> wrote:
>>
>> Hi
>> I've actually implemented something like that with route53 (amazon't DNS
>> service). For each important host (e.g, db) I've created a name (e.g.
>> db.domain.com) and added it as CNAME to the host's internal address (this
>> does not work between regions though). The reason I chose route53 was that 
>> I
>> think (It's not yet checked) that It helps reduces TTL since I already 
>> query
>> the amazon DNS.
>> The update script looks like this:
>> #!/usr/bin/env ruby
>> NODENAME       = <%= %{'#{node.name}'} %>
>> HOSTNAME       = <%= %{'#{node[:ec2][:hostname]}'} %>
>> DOMAINNAME     = <%= %{'#{node[:company][:internal_domain]}'} %>
>> EC2_KEY_ID     = <%= 
>> %{'
 'EC2_KEY_ID']}'}
>>  %>
>> EC2_SECRET_KEY = <%= 
>> %{'
 'EC2_SECRET_KEY']}'}
>>  %>
>> require 'rubygems'
>> require 'right_aws'
>> module Route53Update
>>   extend self
>>   def r53
>>     @r53 ||= RightAws::Route53Interface.new(EC2_KEY_ID, EC2_SECRET_KEY)
>>   end
>>   def zone_id
>>     return @zone_id if @zone_id
>>     zone = r53.list_hosted_zones.select { |zone|
>>       zone[:name] =~ /^#{DOMAINNAME}\.?$/
>>     }.first
>>     @zone_id = zone ? zone[:aws_id] :
>>         raise("Zone #{DOMAINNAME} doesn't seem to be registered!")
>>   end
>>   def create_cname
>>     delete_cname
>>     resource_record_sets = [{
>>       :name             => NODENAME,
>>       :type             => 'CNAME',
>>       :ttl              => 300,
>>       :resource_records => [HOSTNAME]
>>     }]
>>     r53.create_resource_record_sets(zone_id, resource_record_sets, "")
>>   end
>>   def delete_cname
>>     r53.list_resource_record_sets(zone_id).each do |record|
>>       if record[:name] == "#{NODENAME}."
>>         r53.delete_resource_record_sets(zone_id, [record], "")
>>         break
>>       end
>>     end
>>   end
>>   def validate_cname
>>     res = r53.list_resource_record_sets(zone_id).select { |record|
>>       record[:name] =~ /#{NODENAME}\.?$/
>>     }.first
>>     res && res[:resource_records].include?(HOSTNAME) ? true : false
>>   end
>>   def update_cname
>>     return if validate_cname
>>     create_cname
>>     # TODO: validate sync!
>>   end
>> end
>> if $0 == __FILE__
>>   Route53Update.update_cname
>> end
>> You have to install right_aws gem and add an init script (so it'll run on
>> boot). You can probably figure out the variables.
>> Using DNS helps with not having to restart application every time a host
>> changes it IP, but you have to consider DNS caching (e.g, Java caches dns
>> results depending on running environment).
>> HTH
>> Haim
>> On Sun, Nov 20, 2011 at 3:32 PM, Luis Correa d'Almeida 
>> <
 >
>> wrote:
>>>
>>> Let's say I provision two boxes on EC2: db1 and app1
>>>
>>> What's the best way to make each box aware of the other? I need to
>>> tell app1 the IP/host/FQDN of the db1 machine so it can connect to it.
>>>
>>> One option is to use hosts in the config files - for example, in the
>>> app1 box the config references a host (db1) that I can set up either
>>> in the hosts file or in the local DNS. But I still wouldn't know the
>>> IP of db1 to populate the hosts file with when running chef. At this
>>> point, I need to change my data-bags once I find out the address of
>>> db1 and then provision app1, running a recipe that adds the right
>>> entry to the hosts file with the newly found db1 IP.
>>>
>>> Just wondering if there is a better way.
>>>
>>> Thanks,
>>>
>>> Luis
>>
>>
>>
>> --
>> Haim
>
>
>
> --
> Haim
>



-- 
Luis Corrêa d'Almeida
tribe.fm/luis