I am planning a migration from Solaris/x86 to RHEL6. Part of this migration will be migrating services from SMF to the RHEL6 equivalent, which appears to be upstart. While init.d scripts still seem to be supported, I want to take advantage of a more sophisticated init daemon, especially for features like job supervision (restarting etc). I would like to gather some thoughts on a few points:
1) Is upstart an adequate job supervisor, i.e. does it preclude the need for stand-alone managers like daemontools/supervise?
2) Upstart scripts seem very bare-bones compared to a typical init.d script. If I was porting an init.d script to Upstart, is it OK to just "exec /etc/init.d/myjob start"? This include RHEL installed programs like httpd.
3) Does upstart do anything is regards to pid files, and what are it's expectations in regards to the forking model of the process?
4) Are there any straightforward guides to the process management aspect of Upstart...and by that I mean the conditions around controlling restarting? e.g. how many times to restart the process before it goes into a maintenance state, or to ignore errors/core dumps in child processes of the supervised process.
Any other relevant ideas or guides would be appreciated.