Comment 2 for bug 1183614

to make the subprocess metadata proxy leave a log, currently, we need to start the parent process with log_dir or log_file set. I think it is the production way(maybe we need syslog too). In devstack, it can use SCREEN_LOGDIR to catch the parent process's stdout log to a log file. Without setting the log_dir or log_file of l3 or dhcp agent process, the metadata proxy process can not do logging.

I think devstack is for concept-proof or sales demo or some easy stuff. So options are:
1. leave it alone. If devstacker wants to see the logs of metadata proxy, he/she must stop related screen process, and edit the generated quantum.conf, l3 or dhcp configure file to set log_dir or log_file of l3 agent or dhcp agent

2. we add a configuration item for metadata proxy, such as metadata_proxy_log_dir, and let devstack script to set it as the same SCREEN_LOGDIR. metadata proxy will do logging regardless of the log_dir or log_file of parent process.

3. let the metadata proxy do logging to stdout as parent processes are doing.
metadata proxy is started as daemon subprocess, so it seems impossible

4. let the metadata proxy do logging to syslog
first, if parent is using syslog, we can use syslog for metadata proxy too. but it does not fix the devstack problem. In devstack, parent process is doing logging to stdout.