/etc/init/system-services.conf has the following comment:

 # Jobs that depend on system-services as described above can assume the
 # following:
 #   * All services implied by 'boot-services' are available.

This is correct 99.9% of time, but unless I'm missing something, there seems to be no real synchronization between boot-services and system-services.

With the following test Upstart jobs, system-services jobs are started before boot-services' "exec sleep 24h" lines are executed. Can we just ignore such an extreme case, or is it better to rewrite the comment? I'm not really sure if this is worth fixing, but filing this as a feature request for the record.


Test scripts:

localhost ~ # cat /etc/init/boot-test.conf 
start on started boot-services

pre-start script
  exec >> /var/log/test.log 2>&1
  echo "$(date --rfc-3339=ns): pre-start boot-test.conf"
  sleep 30
  exec sleep 24h
end script

localhost ~ # cat /etc/init/boot-test-2.conf 
start on started boot-services

script
  exec >> /var/log/test.log 2>&1
  echo "$(date --rfc-3339=ns): start boot-test-2.conf"
  sleep 30
  exec sleep 24h
end script

localhost ~ # cat /etc/init/system-test.conf 
start on started system-services

pre-start script
  exec >> /var/log/test.log 2>&1
  echo "$(date --rfc-3339=ns): pre-start system-test.conf"
  exec sleep 24h
end script

localhost ~ # cat /etc/init/system-test-2.conf 
start on started system-services

script
  exec >> /var/log/test.log 2>&1
  echo "$(date --rfc-3339=ns): start system-test-2.conf"
  exec sleep 24h
end script


Test result:

localhost ~ # cat /var/log/test.log 
2017-06-09 15:18:47.005118578-07:00: start boot-test-2.conf
2017-06-09 15:18:47.005569162-07:00: pre-start boot-test.conf
2017-06-09 15:18:52.526157017-07:00: pre-start system-test.conf
2017-06-09 15:18:52.532803346-07:00: start system-test-2.conf

system-test* jobs were started without waiting for 'sleep 30' to finish.