Re: using runit as init

[Mike Buland <mike@geekgene.com>]

Hey, a complicated program they made is better than one I have to manage.

If you do read the docs, they don't handle signals in mysqld, like I say, 
mysqlmanager does.  They don't defend it, but they do explain that the only 
way to safely shutdown mysql is to send it a command via the named socket.  
Since this can't be done easily from the commandline without a password, 
unless you configrue mysql to accept the command from root without a 
password, then this seems like a pretty decent solution, since this program 
basically supervises it's child mysql processes and sends them a safe 
shutdown signal when the mysqlmanager program receives a term signal.

All the scripts I've read from debian and redhat just send a kill...although 
this seems alright most of the time (and they are official scripts), that 
doesn't gurantee that data is flushed to disk, if mysql is in the middle of a 
large operation, that data is gone.  This solution does solve that problem, 
and keep runit from waiting for mysql to TERM.

--Mike

On Sunday 13 January 2008 11:39:56 am Charlie Brady wrote:
> On Sun, 13 Jan 2008, Mike Buland wrote:
> > On Sunday 13 January 2008 08:36:31 am Charlie Brady wrote:
> >> On Sat, 12 Jan 2008, Vincent Danen wrote:
> >>> mysqld is no more complex than anything else.
> >>
> >> Have they fixed it then, so that the master process kills children
> >> before dying?
> >
> > Yes, read the (very lame) docs on mysqlmanager.  It also now responds to
> > other signals (such as term) so it plays nicely with runit :)
>
> This might actually mean "no". They haven't fixed the signal
> handling in mysqld, but have instead introduced a new complicated program
> to try to work around the issues.
>
> > mysqlmanager was introduced sometime in mysql 5, not sure when.
>
> Introduced in 5.0.3. Not used by default since 5.0.4.