Ok, I created a wrapper:
/usr/bin/ruby.wrapper with the contents:
#!/bin/bash
/usr/bin/ruby -r rubygems "$@"
changed first line of the ruby-pdns scripts to run the wrapper instead of the ruby binary. Powerdns starts properly:
Feb 18 15:35:30 debian pdns[10261]: Done launching threads, ready to distribute questions
Feb 18 15:35:30 debian pdns[10261]: Backend launched with banner: OK#011Ruby PDNS backend starting
Feb 18 15:35:30 debian pdns[10261]: gmysql Connection successful
Feb 18 15:35:30 debian pdns[10261]: Backend launched with banner: OK#011Ruby PDNS backend starting
Feb 18 15:35:30 debian pdns[10261]: Backend launched with banner: OK#011Ruby PDNS backend starting
pipe backend starts properly:
W, [2013-02-18T15:35:30.395195 #10269] WARN -- : 10269 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.395331 #10269] INFO -- : 10269 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10269
W, [2013-02-18T15:35:30.395907 #10268] WARN -- : 10268 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.396025 #10268] INFO -- : 10268 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10268
W, [2013-02-18T15:35:30.466366 #10272] WARN -- : 10272 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.466535 #10272] INFO -- : 10272 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10272
W, [2013-02-18T15:35:30.467630 #10273] WARN -- : 10273 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.467745 #10273] INFO -- : 10273 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10273
W, [2013-02-18T15:35:30.503240 #10278] WARN -- : 10278 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.503372 #10278] INFO -- : 10278 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10278
W, [2013-02-18T15:35:30.557075 #10280] WARN -- : 10280 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.557216 #10280] INFO -- : 10280 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10280
W, [2013-02-18T15:35:30.575551 #10283] WARN -- : 10283 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.575670 #10283] INFO -- : 10283 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10283
W, [2013-02-18T15:35:30.645069 #10286] WARN -- : 10286 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.645216 #10286] INFO -- : 10286 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10286
W, [2013-02-18T15:35:30.647796 #10289] WARN -- : 10289 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.647906 #10289] INFO -- : 10289 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10289
W, [2013-02-18T15:35:30.682081 #10292] WARN -- : 10292 runner.rb:27:in `initialize': Runner starting
I, [2013-02-18T15:35:30.682205 #10292] INFO -- : 10292 runner.rb:209:in `handshake': Ruby PDNS backend starting with PID 10292
But the problem is that the test.test.com.rb record I added in the records directory is ignored: