haproxy/include/proto/backend.h
Willy Tarreau bfc7b7acd8 MAJOR: checks: add support for a new "drain" administrative mode
This patch adds support for a new "drain" mode. So now we have 3 admin
modes for a server :
  - READY
  - DRAIN
  - MAINT

The drain mode disables load balancing but leaves the server up. It can
coexist with maint, except that maint has precedence. It is also inherited
from tracked servers, so just like maint, it's represented with 2 bits.

New functions were designed to set/clear each flag and to propagate the
changes to tracking servers when relevant, and to log the changes. Existing
functions srv_set_adm_maint() and srv_set_adm_ready() were replaced to make
use of the new functions.

Currently the drain mode is not yet used, however the whole logic was tested
with all combinations of set/clear of both flags in various orders to catch
all corner cases.
2014-05-23 14:29:11 +02:00

136 lines
3.8 KiB
C

/*
* include/proto/backend.h
* Functions prototypes for the backend.
*
* Copyright (C) 2000-2012 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_BACKEND_H
#define _PROTO_BACKEND_H
#include <common/config.h>
#include <common/time.h>
#include <types/backend.h>
#include <types/proxy.h>
#include <types/server.h>
#include <types/session.h>
int assign_server(struct session *s);
int assign_server_address(struct session *s);
int assign_server_and_queue(struct session *s);
int connect_server(struct session *s);
int srv_redispatch_connect(struct session *t);
const char *backend_lb_algo_str(int algo);
int backend_parse_balance(const char **args, char **err, struct proxy *curproxy);
int tcp_persist_rdp_cookie(struct session *s, struct channel *req, int an_bit);
int be_downtime(struct proxy *px);
void recount_servers(struct proxy *px);
void update_backend_weight(struct proxy *px);
struct server *get_server_sh(struct proxy *px, const char *addr, int len);
struct server *get_server_uh(struct proxy *px, char *uri, int uri_len);
int be_lastsession(const struct proxy *be);
/* set the time of last session on the backend */
static void inline be_set_sess_last(struct proxy *be)
{
be->be_counters.last_sess = now.tv_sec;
}
/* This function returns non-zero if the designated server is usable for LB
* according to its current weight and current state. Otherwise it returns 0.
*/
static inline int srv_is_usable(const struct server *srv)
{
enum srv_state state = srv->state;
if (!srv->eweight)
return 0;
if (srv->admin & SRV_ADMF_MAINT)
return 0;
if (srv->admin & SRV_ADMF_DRAIN)
return 0;
switch (state) {
case SRV_ST_STARTING:
case SRV_ST_RUNNING:
return 1;
case SRV_ST_STOPPING:
case SRV_ST_STOPPED:
return 0;
}
return 0;
}
/* This function returns non-zero if the designated server was usable for LB
* according to its current weight and previous state. Otherwise it returns 0.
*/
static inline int srv_was_usable(const struct server *srv)
{
enum srv_state state = srv->prev_state;
if (!srv->prev_eweight)
return 0;
if (srv->prev_admin & SRV_ADMF_MAINT)
return 0;
if (srv->prev_admin & SRV_ADMF_DRAIN)
return 0;
switch (state) {
case SRV_ST_STARTING:
case SRV_ST_RUNNING:
return 1;
case SRV_ST_STOPPING:
case SRV_ST_STOPPED:
return 0;
}
return 0;
}
/* This function commits the current server state and weight onto the previous
* ones in order to detect future changes.
*/
static inline void srv_lb_commit_status(struct server *srv)
{
srv->prev_state = srv->state;
srv->prev_admin = srv->admin;
srv->prev_eweight = srv->eweight;
}
/* This function returns true when a server has experienced a change since last
* commit on its state or weight, otherwise zero.
*/
static inline int srv_lb_status_changed(const struct server *srv)
{
return (srv->state != srv->prev_state ||
srv->admin != srv->prev_admin ||
srv->eweight != srv->prev_eweight);
}
/* sends a log message when a backend goes down, and also sets last
* change date.
*/
void set_backend_down(struct proxy *be);
#endif /* _PROTO_BACKEND_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/