Unfortunately there is no formal documentation that explains the Whirr core but let me try to give you a quick overview:
* the deployment of a cluster is a multi-phase process * the architecture is described using a cluster specification stored as a .properties file. This file has both role assignments and configuration properties for each service as needed * before 0.8.0 we only had 3 phases: bootstrap (install), configure, destroy * in 0.8.0 we want to improve the cluster management capabilities by adding start, stop, cleanup (uninstall) * we are making extensive use of jclouds for machine provisioning and script execution * we are using the compute and the blobstore APIs * in the bootstrap phase we make machine provisioning requests and we execute the bootstrap / service install scripts * the bootstrap phase is resilient to machine failure * this is the phase you need to change to be able to make use of cluster compute instances and placement groups * see https://github.com/apache/whirr/blob/trunk/core/src/main/java/org/apache/whirr/compute/BootstrapTemplate.java * in the configure phase we usually generate configuration files based on machine IPs and hostnames * we ship those files and a set of scripts in parallel for execution on the cluster machines I am sure you will have more questions as you go through the code and we are available to answer them either on the email list or on IRC at #whirr (freenode). To understand the structure of a service you can check the following presentations: https://cwiki.apache.org/confluence/display/WHIRR/Presentations ... and the implementation for a simple one (e.g. elasticsearch or zookeeper). -- Andrei Savu / andreisavu.ro On Wed, Mar 21, 2012 at 9:56 PM, Sean Zhang <[email protected]> wrote: > Is there some high level design document for the project? I would like to > read something before start digging into the code. anything you can suggest? > > Thanks, > Sean > > > On Wed, Mar 21, 2012 at 3:53 PM, Andrei Savu <[email protected]>wrote: > >> >> On Wed, Mar 21, 2012 at 8:49 PM, Sean Zhang <[email protected]> wrote: >> >>> could it be something related to: >>> https://issues.apache.org/jira/browse/WHIRR-63 >>> >> >> I think you may be right but I'm not sure - I've never tried to start a >> cluster compute instance before. >> >> You are more than welcome to lead the effort of making #63 a reality! :) >> > >
