Re: Can monit block/wait on start/stop exec at all? (Chris McKenzie

[Jan-Henrik Haukeland]

On 17. mai. 2007, at 19.38, Chris McKenzie wrote:

> I want to know if I can get monit to wait for the program exec

On stop and restart, monit will in fact wait for the program to stop  
(see control.c and the function do_stop). On restart, monit waits  
until the program is stopped before it starts the program again. The  
way monit does this is first to call the process stop program and  
then go into a loop and check if either the pid in the pid file is  
gone or if the pid file itself is gone. If this is the case it goes  
on to call the start program again otherwise an alert error is raised.

There will be a problem if the program to be stopped removes its pid  
file before it is actually stopped. Normally one of the last thing a  
daemon program should do is to remove its pid file. If it does this  
earlier in the shutdown process there is going to be a problem since  
monit then will assume that the process is gone (because the pid file  
is gone) and continue and call the start program.

Looking at the monit code now I can see that this can be improved by  
caching the pid before calling stop and instead of testing for the  
existence of both the pid file and process id only test for the  
process id. I'll see if I can hack a solution and I'll let you know  
when it can be tested.

Best regards
--
Jan-Henrik Haukeland
http://tildeslash.com/