[c3-users] Unable to construct an c3.conf containing indirect cluster

Thomas Naughton naughtont at ornl.gov
Fri Mar 28 11:16:55 EDT 2008


Nicolas,

Yes, after looking at things again and better understanding what you want
to do.  I don't believe you can make references to other C3 cluster
definitions from the body of a C3 cluster definition block.

The C3 cluster blocks only contain references to machines.  The indirect
references are to point at remote machines, which can be a little as just
the headnode, or include the node details as well.  One caution with
indirect references is to avoid circular definitions, e.g., cluster Foo
references cluster Bar, but the config file on Bar references Foo...loop!

In order to have the "All" approach you requested I believe you have two
basic options:
   1) Create the c3.conf with the "db_servers" and "app_servers" cluster
      block and use the '--all' command line option to perform the command
      on all nodes in all clusters contained in the c3.conf.  Example,

          $ cexec --all hostname


   2) Reference the two clusters in the command line machine definition.
      Example,

          $ cexec  db_servers:  app_servers:  hostname
       or
          $ cexec  db_servers:1,3  app_servers:1-5  hostname


Note, the first cluster in the c3.conf has special meaning, it is the
default used when not specifying a cluster on the command line, i.e.,
if the "db_servers" were the first to appear, then by default all commands
would by default operate on this block.

An example c3.conf for above discussion:

     cluster db_servers {
              dbs1.example.com:node0
              dead dummy    #skip index 0
              node1
              node2
              node3
      }

      cluster app_servers {
               apps1.example.com:node0
               dead dummy   #skip index 0
               node1
               node2
               node3
               node4
               node5
      }


I hope that helps.  Please let us know if you have further questions.
--tjn

PS  If interested I can Fwd you a paper based on a slightly older version
     of C3 that discusses some details/examples  (DAPSYS'02).

  _________________________________________________________________________
   Thomas Naughton                                      naughtont at ornl.gov
   Research Associate                                   (865) 576-4184


On Fri, 28 Mar 2008, Nicolas Cros wrote:

> Thomas
>
> Thank you very much for your answer. I understand better the indirect 
> cluster.
>
> I can not use this feature in my case, as what i want to do is to include a 
> cluster inside another one.
>
> Say I have a cluster named 'db-servers', another 'app-servers' , and i want 
> to create a cluster named "all", which redirects to cluster 'db-servers' and 
> 'app-servers'
>
>
>> Nicolas,
>> 
>> There is an example in the C3.CONF(5) manual page. 
>> http://www.csm.ornl.gov/torc/C3/Man/c3.conf.shtml
>> 
>> The syntax is usually something like:
>>
>>      cluster torc {
>>           :node0
>>      }
>> 
>> It is used as a reference to another cluster, and basically just forwards
>> the command to that remote machine, for it to then figure out how to
>> connect to the nodes, i.e., via the '/etc/c3.conf' on that remote cluster.
>> 
>> I hope that helps.  Let us now if you're still having problems.
>> --tjn
>>
>>   _________________________________________________________________________
>>    Thomas Naughton                                      naughtont at ornl.gov
>>    Research Associate                                   (865) 576-4184
>> 
>> 
>> On Thu, 20 Mar 2008, Nicolas Cros wrote:
>> 
>>> Hello,
>>> I'm not able to define an indirect cluster containing 2 clusters.
>>> Do you have an example please ?
>>> 
>>> Here is my configuraiton file :
>>> 
>>> cluster dium-qt {
>>>       dium-dev:dium-dev
>>>       dium-sfr-qt
>>>       dium-trm-qt
>>>       dium-web-qt
>>> }
>>> cluster dium-qo {
>>>       dium-dev:dium-dev
>>>       dium-sfr-qo
>>>       dium-trm-qo
>>>       dium-web-qo
>>> }
>>> cluster dium {
>>>       dium-dev:dium-dev
>>>       :dium-qt
>>>       :dium-qo
>>> }
>>> 
>>> Thanks .
>>> 
>>> -- 
>>> Nicolas.Cros at cls.fr             Collecte Localisation Satellites
>>> Administrateur Systeme          8-10 rue Hermes
>>> tel 05.61.39.48.81              Parc Technologique du Canal
>>> fax 05.61.39.48.40              31520 Ramonville St Agne, France
>>> 
>>> 
>
>
> -- 
> Nicolas.Cros at cls.fr             Collecte Localisation Satellites
> Administrateur Systeme          8-10 rue Hermes
> tel 05.61.39.48.81              Parc Technologique du Canal
> fax 05.61.39.48.40              31520 Ramonville St Agne, France
>
>


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