An SMF manifest that works well on the TXD containers. More here, and also see the related Capistrano config

<?xml version='1.0'?>
<!DOCTYPE service_bundle SYSTEM '/usr/share/lib/xml/dtd/service_bundle.dtd.1'>
<service_bundle type='manifest' name='mongrel/example'>
  <service name='network/mongrel/example' type='service' version='0'>
    <create_default_instance enabled='true'/>
    <single_instance/>
    
    <dependency name='fs' grouping='require_all' restart_on='none' type='service'>
      <service_fmri value='svc:/system/filesystem/local'/>
    </dependency>
    <dependency name='net' grouping='require_all' restart_on='none' type='service'>
      <service_fmri value='svc:/network/loopback'/>
      <!-- need nfs/client because the mongrel stuff is on /home which is nfs mounted -->
      <service_fmri value='svc:/network/nfs/client'/>
    </dependency>
    <dependent name='mongrel_example' restart_on='none' grouping='optional_all'>
      <service_fmri value='svc:/milestone/multi-user'/>
    </dependent>
    
    <exec_method name='start' type='method' exec='/opt/csw/bin/mongrel_rails cluster::start' timeout_seconds='60'>
      <method_context working_directory='/home/example/rails/example.org/current'>
        <method_credential user='example' group='example' />
        <method_environment>
          <envvar name="PATH" value="/usr/bin:/bin:/opt/csw/bin" />
        </method_environment>
      </method_context>
    </exec_method>

    <exec_method name='stop' type='method' exec=':kill' timeout_seconds='60'>
      <method_context/>
    </exec_method>

  </service>
</service_bundle>

A mostly-standardized Capistrano deploy.rb file for the TXD containers. Adjust :application, :smf, :repository, :deploy_to as required; adjust the role definitions too if you want to use different hosts.

Copy your database.yml file to /home/example/rails/example.org/shared/config/database.yml and it'll get symlinked into place before the app is restarted.

This works with my SMF manifest here

set :application, "example.org"
set :smf, "mongrel/example"
set :repository, "https://example.textdriven.com/svn/#{application}"
set :deploy_to, "/home/example/rails/#{application}"
role :web, "#{application}", :primary => true
role :app, "#{application}", :primary => true
role :db, "#{application}", :primary => true

set :checkout, "export"
set :svn, "/opt/csw/bin/svn"
set :sudo, "/opt/csw/bin/sudo"
set :rake, "/opt/csw/bin/rake"

task :after_update_code do
  run "ln -s #{deploy_to}/#{shared_dir}/config/database.yml #{current_release}/config/database.yml"
  run "rm -f #{current_path}"
end

task :spinner, :roles => :app do
  send(run_method, "/usr/sbin/svcadm start #{smf}")
end

task :restart, :roles => :app do
  send(run_method, "/usr/sbin/svcadm restart #{smf}")
end