haproxy/include/proto/checks.h
Krzysztof Oledzki b304dc7fd7 [MEDIUM] Spread health checks even more
When one server appears at the same position in multiple backends, it
receives all the checks from all the backends exactly at the same time
because the health-checks are only spread within a backend but not
globally.

Attached patch implements per-server start delay in a different way.
Checks are now spread globally - not locally to one backend. It also makes
them start faster - IMHO there is no need to add a 'server->inter' when
calculating first execution. Calculation were moved from cfgparse.c to
checks.c. There is a new function start_checks() and now it is not called
when haproxy is started in MODE_CHECK.

With this patch it is also possible to set a global 'spread-checks'
parameter. It takes a percentage value (1..50, probably something near
5..10 is a good idea) so haproxy adds or removes that many percent to the
original interval after each check. My test shows that with 18 backends,
54 servers total and 10000ms/5% it takes about 45m to mix them completely.

I decided to use rand/srand pseudo-random number generator. I am aware it
is not recommend for a good randomness but a) we do not need a good random
generator here b) it is probably the most portable one.
2007-10-15 09:33:10 +02:00

39 lines
1.1 KiB
C

/*
include/proto/checks.h
Functions prototypes for the checks.
Copyright (C) 2000-2007 Willy Tarreau - w@1wt.eu
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation, version 2.1
exclusively.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_CHECKS_H
#define _PROTO_CHECKS_H
#include <types/task.h>
#include <common/config.h>
void process_chk(struct task *t, struct timeval *next);
int start_checks();
#endif /* _PROTO_CHECKS_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/