Nginx reload problem

[Maxim Dounin]

Hello!

On Fri, Aug 16, 2013 at 10:16:16PM -0400, B.R. wrote:

> I guess it would be nice if the doc warned about directives that need a
> server restart to be reloaded.
> 
> Everyone supposes (as it seems obvious) that reloading Nginx is enough to
> apply configuration changes.

Reloading is enough.  What is very wrong is to assume that sending 
a HUP signal to nginx is enough for a reload.  For various 
reasons, ranging from configuration syntax errors to out of memory 
problems, configuration reload might fail.

Quoting documentation:

... If this fails, it rolls back changes and continues to work 
with old configuration. ...

http://nginx.org/en/docs/control.html#reconfiguration

> An interesting part of the question was the inquiry about the potential
> existence other directives requiring a server restart rather than its
> reload. Do you have intel on this Maxim?

There are no directives which require a server restart.  But some 
changes are not possible on the fly - e.g. you can't change a 
shared memory zone size.  If you want to change it - you have to 
create another shared memory zone, or use a binary upgrade which 
doesn't inherit shared memory zones and their contents (or use a 
restart, which will obviously work as well).

-- 
Maxim Dounin
http://nginx.org/en/donation.html