mirror of
https://github.com/nginx/nginx.git
synced 2025-08-01 02:56:15 +08:00
Upstream: smooth weighted round-robin balancing.
For edge case weights like { 5, 1, 1 } we now produce { a, a, b, a, c, a, a }
sequence instead of { c, b, a, a, a, a, a } produced previously.
Algorithm is as follows: on each peer selection we increase current_weight
of each eligible peer by its weight, select peer with greatest current_weight
and reduce its current_weight by total number of weight points distributed
among peers.
In case of { 5, 1, 1 } weights this gives the following sequence of
current_weight's:
a b c
0 0 0 (initial state)
5 1 1 (a selected)
-2 1 1
3 2 2 (a selected)
-4 2 2
1 3 3 (b selected)
1 -4 3
6 -3 4 (a selected)
-1 -3 4
4 -2 5 (c selected)
4 -2 -2
9 -1 -1 (a selected)
2 -1 -1
7 0 0 (a selected)
0 0 0
To preserve weight reduction in case of failures the effective_weight
variable was introduced, which usually matches peer's weight, but is
reduced temporarily on peer failures.
This change also fixes loop with backup servers and proxy_next_upstream
http_404 (ticket #47), and skipping alive upstreams in some cases if there
are multiple dead ones (ticket #64).
This commit is contained in:
Maxim Dounin
parent
e302ed6fc3
commit
52327e0627
@ -12,8 +12,8 @@
|
||||
|
||||
static ngx_int_t ngx_http_upstream_cmp_servers(const void *one,
|
||||
const void *two);
|
||||
static ngx_uint_t
|
||||
ngx_http_upstream_get_peer(ngx_http_upstream_rr_peers_t *peers);
|
||||
static ngx_http_upstream_rr_peer_t *ngx_http_upstream_get_peer(
|
||||
ngx_http_upstream_rr_peer_data_t *rrp);
|
||||
|
||||
#if (NGX_HTTP_SSL)
|
||||
|
||||
@ -81,7 +81,8 @@ ngx_http_upstream_init_round_robin(ngx_conf_t *cf,
|
||||
peers->peer[n].fail_timeout = server[i].fail_timeout;
|
||||
peers->peer[n].down = server[i].down;
|
||||
peers->peer[n].weight = server[i].down ? 0 : server[i].weight;
|
||||
peers->peer[n].current_weight = peers->peer[n].weight;
|
||||
peers->peer[n].effective_weight = peers->peer[n].weight;
|
||||
peers->peer[n].current_weight = 0;
|
||||
n++;
|
||||
}
|
||||
}
|
||||
@ -131,7 +132,8 @@ ngx_http_upstream_init_round_robin(ngx_conf_t *cf,
|
||||
backup->peer[n].socklen = server[i].addrs[j].socklen;
|
||||
backup->peer[n].name = server[i].addrs[j].name;
|
||||
backup->peer[n].weight = server[i].weight;
|
||||
backup->peer[n].current_weight = server[i].weight;
|
||||
backup->peer[n].effective_weight = server[i].weight;
|
||||
backup->peer[n].current_weight = 0;
|
||||
backup->peer[n].max_fails = server[i].max_fails;
|
||||
backup->peer[n].fail_timeout = server[i].fail_timeout;
|
||||
backup->peer[n].down = server[i].down;
|
||||
@ -190,7 +192,8 @@ ngx_http_upstream_init_round_robin(ngx_conf_t *cf,
|
||||
peers->peer[i].socklen = u.addrs[i].socklen;
|
||||
peers->peer[i].name = u.addrs[i].name;
|
||||
peers->peer[i].weight = 1;
|
||||
peers->peer[i].current_weight = 1;
|
||||
peers->peer[i].effective_weight = 1;
|
||||
peers->peer[i].current_weight = 0;
|
||||
peers->peer[i].max_fails = 1;
|
||||
peers->peer[i].fail_timeout = 10;
|
||||
}
|
||||
@ -306,7 +309,8 @@ ngx_http_upstream_create_round_robin_peer(ngx_http_request_t *r,
|
||||
peers->peer[0].socklen = ur->socklen;
|
||||
peers->peer[0].name = ur->host;
|
||||
peers->peer[0].weight = 1;
|
||||
peers->peer[0].current_weight = 1;
|
||||
peers->peer[0].effective_weight = 1;
|
||||
peers->peer[0].current_weight = 0;
|
||||
peers->peer[0].max_fails = 1;
|
||||
peers->peer[0].fail_timeout = 10;
|
||||
|
||||
@ -338,7 +342,8 @@ ngx_http_upstream_create_round_robin_peer(ngx_http_request_t *r,
|
||||
peers->peer[i].name.len = len;
|
||||
peers->peer[i].name.data = p;
|
||||
peers->peer[i].weight = 1;
|
||||
peers->peer[i].current_weight = 1;
|
||||
peers->peer[i].effective_weight = 1;
|
||||
peers->peer[i].current_weight = 0;
|
||||
peers->peer[i].max_fails = 1;
|
||||
peers->peer[i].fail_timeout = 10;
|
||||
}
|
||||
@ -378,8 +383,6 @@ ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
|
||||
{
|
||||
ngx_http_upstream_rr_peer_data_t *rrp = data;
|
||||
|
||||
time_t now;
|
||||
uintptr_t m;
|
||||
ngx_int_t rc;
|
||||
ngx_uint_t i, n;
|
||||
ngx_connection_t *c;
|
||||
@ -389,8 +392,6 @@ ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
|
||||
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
|
||||
"get rr peer, try: %ui", pc->tries);
|
||||
|
||||
now = ngx_time();
|
||||
|
||||
/* ngx_lock_mutex(rrp->peers->mutex); */
|
||||
|
||||
if (rrp->peers->last_cached) {
|
||||
@ -423,118 +424,15 @@ ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
|
||||
|
||||
/* there are several peers */
|
||||
|
||||
if (pc->tries == rrp->peers->number) {
|
||||
peer = ngx_http_upstream_get_peer(rrp);
|
||||
|
||||
/* it's a first try - get a current peer */
|
||||
|
||||
i = pc->tries;
|
||||
|
||||
for ( ;; ) {
|
||||
rrp->current = ngx_http_upstream_get_peer(rrp->peers);
|
||||
|
||||
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
|
||||
"get rr peer, current: %ui %i",
|
||||
rrp->current,
|
||||
rrp->peers->peer[rrp->current].current_weight);
|
||||
|
||||
n = rrp->current / (8 * sizeof(uintptr_t));
|
||||
m = (uintptr_t) 1 << rrp->current % (8 * sizeof(uintptr_t));
|
||||
|
||||
if (!(rrp->tried[n] & m)) {
|
||||
peer = &rrp->peers->peer[rrp->current];
|
||||
|
||||
if (!peer->down) {
|
||||
|
||||
if (peer->max_fails == 0
|
||||
|| peer->fails < peer->max_fails)
|
||||
{
|
||||
break;
|
||||
}
|
||||
|
||||
if (now - peer->checked > peer->fail_timeout) {
|
||||
peer->checked = now;
|
||||
break;
|
||||
}
|
||||
|
||||
peer->current_weight = 0;
|
||||
|
||||
} else {
|
||||
rrp->tried[n] |= m;
|
||||
}
|
||||
|
||||
pc->tries--;
|
||||
}
|
||||
|
||||
if (pc->tries == 0) {
|
||||
goto failed;
|
||||
}
|
||||
|
||||
if (--i == 0) {
|
||||
ngx_log_error(NGX_LOG_ALERT, pc->log, 0,
|
||||
"round robin upstream stuck on %ui tries",
|
||||
pc->tries);
|
||||
goto failed;
|
||||
}
|
||||
}
|
||||
|
||||
peer->current_weight--;
|
||||
|
||||
} else {
|
||||
|
||||
i = pc->tries;
|
||||
|
||||
for ( ;; ) {
|
||||
n = rrp->current / (8 * sizeof(uintptr_t));
|
||||
m = (uintptr_t) 1 << rrp->current % (8 * sizeof(uintptr_t));
|
||||
|
||||
if (!(rrp->tried[n] & m)) {
|
||||
|
||||
peer = &rrp->peers->peer[rrp->current];
|
||||
|
||||
if (!peer->down) {
|
||||
|
||||
if (peer->max_fails == 0
|
||||
|| peer->fails < peer->max_fails)
|
||||
{
|
||||
break;
|
||||
}
|
||||
|
||||
if (now - peer->checked > peer->fail_timeout) {
|
||||
peer->checked = now;
|
||||
break;
|
||||
}
|
||||
|
||||
peer->current_weight = 0;
|
||||
|
||||
} else {
|
||||
rrp->tried[n] |= m;
|
||||
}
|
||||
|
||||
pc->tries--;
|
||||
}
|
||||
|
||||
rrp->current++;
|
||||
|
||||
if (rrp->current >= rrp->peers->number) {
|
||||
rrp->current = 0;
|
||||
}
|
||||
|
||||
if (pc->tries == 0) {
|
||||
goto failed;
|
||||
}
|
||||
|
||||
if (--i == 0) {
|
||||
ngx_log_error(NGX_LOG_ALERT, pc->log, 0,
|
||||
"round robin upstream stuck on %ui tries",
|
||||
pc->tries);
|
||||
goto failed;
|
||||
}
|
||||
}
|
||||
|
||||
peer->current_weight--;
|
||||
if (peer == NULL) {
|
||||
goto failed;
|
||||
}
|
||||
|
||||
rrp->tried[n] |= m;
|
||||
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
|
||||
"get rr peer, current: %ui %i",
|
||||
rrp->current, peer->current_weight);
|
||||
}
|
||||
|
||||
pc->sockaddr = peer->sockaddr;
|
||||
@ -545,11 +443,6 @@ ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
|
||||
|
||||
if (pc->tries == 1 && rrp->peers->next) {
|
||||
pc->tries += rrp->peers->next->number;
|
||||
|
||||
n = rrp->peers->next->number / (8 * sizeof(uintptr_t)) + 1;
|
||||
for (i = 0; i < n; i++) {
|
||||
rrp->tried[i] = 0;
|
||||
}
|
||||
}
|
||||
|
||||
return NGX_OK;
|
||||
@ -595,56 +488,71 @@ failed:
|
||||
}
|
||||
|
||||
|
||||
static ngx_uint_t
|
||||
ngx_http_upstream_get_peer(ngx_http_upstream_rr_peers_t *peers)
|
||||
static ngx_http_upstream_rr_peer_t *
|
||||
ngx_http_upstream_get_peer(ngx_http_upstream_rr_peer_data_t *rrp)
|
||||
{
|
||||
ngx_uint_t i, n, reset = 0;
|
||||
ngx_http_upstream_rr_peer_t *peer;
|
||||
time_t now;
|
||||
uintptr_t m;
|
||||
ngx_int_t total;
|
||||
ngx_uint_t i, n;
|
||||
ngx_http_upstream_rr_peer_t *peer, *best;
|
||||
|
||||
peer = &peers->peer[0];
|
||||
now = ngx_time();
|
||||
|
||||
for ( ;; ) {
|
||||
best = NULL;
|
||||
total = 0;
|
||||
|
||||
for (i = 0; i < peers->number; i++) {
|
||||
for (i = 0; i < rrp->peers->number; i++) {
|
||||
|
||||
if (peer[i].current_weight <= 0) {
|
||||
continue;
|
||||
}
|
||||
n = i / (8 * sizeof(uintptr_t));
|
||||
m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
|
||||
|
||||
n = i;
|
||||
|
||||
while (i < peers->number - 1) {
|
||||
|
||||
i++;
|
||||
|
||||
if (peer[i].current_weight <= 0) {
|
||||
continue;
|
||||
}
|
||||
|
||||
if (peer[n].current_weight * 1000 / peer[i].current_weight
|
||||
> peer[n].weight * 1000 / peer[i].weight)
|
||||
{
|
||||
return n;
|
||||
}
|
||||
|
||||
n = i;
|
||||
}
|
||||
|
||||
if (peer[i].current_weight > 0) {
|
||||
n = i;
|
||||
}
|
||||
|
||||
return n;
|
||||
if (rrp->tried[n] & m) {
|
||||
continue;
|
||||
}
|
||||
|
||||
if (reset++) {
|
||||
return 0;
|
||||
peer = &rrp->peers->peer[i];
|
||||
|
||||
if (peer->down) {
|
||||
continue;
|
||||
}
|
||||
|
||||
for (i = 0; i < peers->number; i++) {
|
||||
peer[i].current_weight = peer[i].weight;
|
||||
if (peer->max_fails
|
||||
&& peer->fails >= peer->max_fails
|
||||
&& now - peer->checked <= peer->fail_timeout)
|
||||
{
|
||||
continue;
|
||||
}
|
||||
|
||||
peer->current_weight += peer->effective_weight;
|
||||
total += peer->effective_weight;
|
||||
|
||||
if (peer->effective_weight < peer->weight) {
|
||||
peer->effective_weight++;
|
||||
}
|
||||
|
||||
if (best == NULL || peer->current_weight > best->current_weight) {
|
||||
best = peer;
|
||||
}
|
||||
}
|
||||
|
||||
if (best == NULL) {
|
||||
return NULL;
|
||||
}
|
||||
|
||||
i = best - &rrp->peers->peer[0];
|
||||
|
||||
rrp->current = i;
|
||||
|
||||
n = i / (8 * sizeof(uintptr_t));
|
||||
m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
|
||||
|
||||
rrp->tried[n] |= m;
|
||||
|
||||
best->current_weight -= total;
|
||||
best->checked = now;
|
||||
|
||||
return best;
|
||||
}
|
||||
|
||||
|
||||
@ -683,15 +591,15 @@ ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
|
||||
peer->checked = now;
|
||||
|
||||
if (peer->max_fails) {
|
||||
peer->current_weight -= peer->weight / peer->max_fails;
|
||||
peer->effective_weight -= peer->weight / peer->max_fails;
|
||||
}
|
||||
|
||||
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
|
||||
"free rr peer failed: %ui %i",
|
||||
rrp->current, peer->current_weight);
|
||||
rrp->current, peer->effective_weight);
|
||||
|
||||
if (peer->current_weight < 0) {
|
||||
peer->current_weight = 0;
|
||||
if (peer->effective_weight < 0) {
|
||||
peer->effective_weight = 0;
|
||||
}
|
||||
|
||||
/* ngx_unlock_mutex(rrp->peers->mutex); */
|
||||
@ -705,12 +613,6 @@ ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
|
||||
}
|
||||
}
|
||||
|
||||
rrp->current++;
|
||||
|
||||
if (rrp->current >= rrp->peers->number) {
|
||||
rrp->current = 0;
|
||||
}
|
||||
|
||||
if (pc->tries) {
|
||||
pc->tries--;
|
||||
}
|
||||
|
||||
@ -20,6 +20,7 @@ typedef struct {
|
||||
ngx_str_t name;
|
||||
|
||||
ngx_int_t current_weight;
|
||||
ngx_int_t effective_weight;
|
||||
ngx_int_t weight;
|
||||
|
||||
ngx_uint_t fails;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user