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From Joshua Slive <>
Subject RE: Reload CRL without re-starting Apache
Date Tue, 25 May 2004 18:20:25 GMT

On Tue, 25 May 2004, Mathihalli, Madhusudan wrote:
>>> Here's the current logic :
>>> - user invokes "apachectl updatecrl" which sends a SIGUSR2 signal to
>>> the parent process
>> Question from an innocent bystander: Is there some reason that
>> "apachectl
>> graceful" isn't good enough for this situation?
> AIUI, the 'graceful' restart forces the child processes join all the
> threads and re-start. (Pl. let me know if this is incorrect).
> The requirement is to update the crl without causing the process to
> re-start in order to achieve a zero down-time.

Yes, the "graceful" restart does force all the child process/threads to 
restart.  But it does so in a "graceful" manner: workers are not killed 
until they are done serving requests and new workers are started before 
the old ones are killed in order to assure that there is always a pool of 
workers available to serve new connections.

Theoretically, "apachectl graceful" should have zero down-time from the 
client perspective.

Of course, this recycling will cause some extra load on the server, so 
having a method of reloading arbitrary parts of the configuration is not a 
bad idea.  But whether it is worth the effort over a nice, clean 
"apachectl graceful", I couldn't say.


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