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Commit 616a9be2 authored by Kenny Mathis's avatar Kenny Mathis Committed by Simon Horman
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ipvs: Add simple weighted failover scheduler 



Add simple weighted IPVS failover support to the Linux kernel. All
other scheduling modules implement some form of load balancing, while
this offers a simple failover solution. Connections are directed to
the appropriate server based solely on highest weight value and server
availability. Tested functionality with keepalived.

Signed-off-by: default avatarKenny Mathis <kmathis@chokepoint.net>
Acked-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarSimon Horman <horms@verge.net.au>
parent 0bbe80e5

net/netfilter/ipvs/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -152,6 +152,16 @@ config IP_VS_WLC 
	  If you want to compile it in kernel, say Y. To compile it as a

	  module, choose M here. If unsure, say N.



config  IP_VS_FO

		tristate "weighted failover scheduling"

	---help---

	  The weighted failover scheduling algorithm directs network

	  connections to the server with the highest weight that is

	  currently available.



	  If you want to compile it in kernel, say Y. To compile it as a

	  module, choose M here. If unsure, say N.



config	IP_VS_LBLC

	tristate "locality-based least-connection scheduling"

	---help---

net/netfilter/ipvs/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ obj-$(CONFIG_IP_VS_RR) += ip_vs_rr.o 
obj-$(CONFIG_IP_VS_WRR) += ip_vs_wrr.o

obj-$(CONFIG_IP_VS_LC) += ip_vs_lc.o

obj-$(CONFIG_IP_VS_WLC) += ip_vs_wlc.o

obj-$(CONFIG_IP_VS_FO) += ip_vs_fo.o

obj-$(CONFIG_IP_VS_LBLC) += ip_vs_lblc.o

obj-$(CONFIG_IP_VS_LBLCR) += ip_vs_lblcr.o

obj-$(CONFIG_IP_VS_DH) += ip_vs_dh.o

net/netfilter/ipvs/ip_vs_fo.c

0 → 100644
+79 −0
Original line number Diff line number Diff line 
/*

 * IPVS:        Weighted Fail Over module

 *

 * Authors:     Kenny Mathis <kmathis@chokepoint.net>

 *

 *              This program is free software; you can redistribute it and/or

 *              modify it under the terms of the GNU General Public License

 *              as published by the Free Software Foundation; either version

 *              2 of the License, or (at your option) any later version.

 *

 * Changes:

 *     Kenny Mathis            :     added initial functionality based on weight

 *

 */



#define KMSG_COMPONENT "IPVS"

#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt



#include <linux/module.h>

#include <linux/kernel.h>



#include <net/ip_vs.h>



/* Weighted Fail Over Module */

static struct ip_vs_dest *

ip_vs_fo_schedule(struct ip_vs_service *svc, const struct sk_buff *skb,

		  struct ip_vs_iphdr *iph)

{

	struct ip_vs_dest *dest, *hweight = NULL;

	int hw = 0; /* Track highest weight */



	IP_VS_DBG(6, "ip_vs_fo_schedule(): Scheduling...\n");



	/* Basic failover functionality

	 * Find virtual server with highest weight and send it traffic

	 */

	list_for_each_entry_rcu(dest, &svc->destinations, n_list) {

		if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) &&

		    atomic_read(&dest->weight) > hw) {

			hweight = dest;

			hw = atomic_read(&dest->weight);

		}

	}



	if (hweight) {

		IP_VS_DBG_BUF(6, "FO: server %s:%u activeconns %d weight %d\n",

			      IP_VS_DBG_ADDR(svc->af, &hweight->addr),

			      ntohs(hweight->port),

			      atomic_read(&hweight->activeconns),

			      atomic_read(&hweight->weight));

		return hweight;

	}



	ip_vs_scheduler_err(svc, "no destination available");

	return NULL;

}



static struct ip_vs_scheduler ip_vs_fo_scheduler = {

	.name =			"fo",

	.refcnt =		ATOMIC_INIT(0),

	.module =		THIS_MODULE,

	.n_list =		LIST_HEAD_INIT(ip_vs_fo_scheduler.n_list),

	.schedule =		ip_vs_fo_schedule,

};



static int __init ip_vs_fo_init(void)

{

	return register_ip_vs_scheduler(&ip_vs_fo_scheduler);

}



static void __exit ip_vs_fo_cleanup(void)

{

	unregister_ip_vs_scheduler(&ip_vs_fo_scheduler);

	synchronize_rcu();

}



module_init(ip_vs_fo_init);

module_exit(ip_vs_fo_cleanup);

MODULE_LICENSE("GPL");