From: Jim Jagielski Date: Thu, 31 May 2018 13:24:04 +0000 (+0000) Subject: Merge r1828890, r1832500 from trunk: X-Git-Tag: 2.4.34~131 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c8a7d27c84ca693263f97cf14d6467bda4c27c2b;p=apache Merge r1828890, r1832500 from trunk: mod_proxy_balancer: Add hot spare member type and corresponding flag (R). Hot spare members are used as drop-in replacements for unusable workers in the same load balancer set. This differs from hot standbys which are only used when all workers in a set are unusable. PR 61140. mod_proxy_balancer: follow up to r1828890: indentation and 80 col. Submitted by: jhriggs, ylavic Reviewed by: jhriggs, jim, ylavic git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1832609 13f79535-47bb-0310-9956-ffa450edef68 --- diff --git a/CHANGES b/CHANGES index 780f729d30..07ede5133a 100644 --- a/CHANGES +++ b/CHANGES @@ -1,6 +1,11 @@ -*- coding: utf-8 -*- Changes with Apache 2.4.34 + *) mod_proxy_balancer: Add hot spare member type and corresponding flag (R). + Hot spare members are used as drop-in replacements for unusable workers + in the same load balancer set. This differs from hot standbys which are + only used when all workers in a set are unusable. PR 61140. [Jim Riggs] + *) suexec: Add --enable-suexec-capabilites support on Linux, to use setuid/setgid capability bits rather than a setuid root binary. [Joe Orton] @@ -5789,4 +5794,3 @@ Changes with Apache 2.2.x and later: Changes with Apache 2.0.x and later: *) http://svn.apache.org/viewvc/httpd/httpd/branches/2.0.x/CHANGES?view=markup - diff --git a/STATUS b/STATUS index fdae7eb119..0d7d5b8e6e 100644 --- a/STATUS +++ b/STATUS @@ -155,15 +155,6 @@ PATCHES ACCEPTED TO BACKPORT FROM TRUNK: jailletc36: There should be a compatibility note for the new directives. (done in r1828478) - *) mod_proxy_balancer: Add hot spare member type and corresponding flag (R). Hot spare members are - used as drop-in replacements for unusable workers in the same load balancer set. This differs - from hot standbys which are only used when all workers in a set are unusable. PR 61140. - trunk patch: https://svn.apache.org/r1828890 - 2.4.x patch: https://svn.apache.org/repos/asf/httpd/httpd/patches/2.4.x/hot-spare-2.4.patch - +1: jhriggs, jim - ylavic: +1 with r1832500. - - PATCHES PROPOSED TO BACKPORT FROM TRUNK: [ New proposals should be added at the end of the list ] diff --git a/docs/manual/howto/reverse_proxy.xml b/docs/manual/howto/reverse_proxy.xml index ca986d36eb..cef737cab3 100644 --- a/docs/manual/howto/reverse_proxy.xml +++ b/docs/manual/howto/reverse_proxy.xml @@ -182,20 +182,41 @@ ProxyPassReverse "/images" "balancer://myset/" Failover

- You can also fine-tune various failover scenarios, detailing which - workers and even which balancers should accessed in such cases. For - example, the below setup implements 2 failover cases: In the first, - http://hstandby.example.com:8080 is only sent traffic - if all other workers in the myset balancer are not available. - If that worker itself is not available, only then will the - http://bkup1.example.com:8080 and http://bkup2.example.com:8080 - workers be brought into rotation: + You can also fine-tune various failover scenarios, detailing which workers + and even which balancers should be accessed in such cases. For example, the + below setup implements three failover cases: +

+
    +
  1. + http://spare1.example.com:8080 and + http://spare2.example.com:8080 are only sent traffic if one + or both of http://www2.example.com:8080 or + http://www3.example.com:8080 is unavailable. (One spare + will be used to replace one unusable member of the same balancer set.) +
    2. +
  2. + http://hstandby.example.com:8080 is only sent traffic if + all other workers in balancer set 0 are not available. +
    3. +
  3. + If all load balancer set 0 workers, spares, and the standby + are unavailable, only then will the + http://bkup1.example.com:8080 and + http://bkup2.example.com:8080 workers from balancer set + 1 be brought into rotation. +
    4. +
+

+ Thus, it is possible to have one or more hot spares and hot standbys for + each load balancer set.

<Proxy balancer://myset> BalancerMember http://www2.example.com:8080 BalancerMember http://www3.example.com:8080 loadfactor=3 timeout=1 + BalancerMember http://spare1.example.com:8080 status=+R + BalancerMember http://spare2.example.com:8080 status=+R BalancerMember http://hstandby.example.com:8080 status=+H BalancerMember http://bkup1.example.com:8080 lbset=1 BalancerMember http://bkup2.example.com:8080 lbset=1 @@ -207,11 +228,12 @@ ProxyPassReverse "/images/" "balancer://myset/"

- The magic of this failover setup is setting http://hstandby.example.com:8080 - with the +H status flag, which puts it in hot standby mode, - and making the 2 bkup# servers part of the #1 load balancer set (the - default set is 0); for failover, hot standbys (if they exist) are used 1st, when all regular - workers are unavailable; load balancer sets are always tried lowest number first. + For failover, hot spares are used as replacements for unusable workers in + the same load balancer set. A worker is considered unusable if it is + draining, stopped, or otherwise in an error/failed state. Hot standbys are + used if all workers and spares in the load balancer set are + unavailable. Load balancer sets (with their respective hot spares and + standbys) are always tried in order from lowest to highest.

@@ -301,8 +323,12 @@ ProxyPassReverse "/images/" "balancer://myset/" SStopWorker is administratively stopped; will not accept requests and will not be automatically retried IIgnWorker is in ignore-errors mode and will always be considered available. + RSparWorker is a hot spare. For each worker in a given lbset that is unusable + (draining, stopped, in error, etc.), a usable hot spare with the same lbset will be used in + its place. Hot spares can help ensure that a specific number of workers are always available + for use by a balancer. HStbyWorker is in hot-standby mode and will only be used if no other - viable workers are available. + viable workers or spares are available in the balancer set. EErrWorker is in an error state, usually due to failing pre-request check; requests will not be proxied to this worker, but it will be retried depending on the retry setting of the worker. diff --git a/docs/manual/mod/mod_proxy.xml b/docs/manual/mod/mod_proxy.xml index b16a2cc83e..1f0c4e127a 100644 --- a/docs/manual/mod/mod_proxy.xml +++ b/docs/manual/mod/mod_proxy.xml @@ -1186,8 +1186,12 @@ ProxyPass "/mirror/foo/i" "!" D: Worker is disabled and will not accept any requests. S: Worker is administratively stopped. I: Worker is in ignore-errors mode and will always be considered available. + R: Worker is a hot spare. For each worker in a given lbset that is unusable + (draining, stopped, in error, etc.), a usable hot spare with the same lbset will be used in + its place. Hot spares can help ensure that a specific number of workers are always available + for use by a balancer. H: Worker is in hot-standby mode and will only be used if no other - viable workers are available. + viable workers or spares are available in the balancer set. E: Worker is in an error state. N: Worker is in drain mode and will only accept existing sticky sessions destined for itself and ignore all other requests. @@ -1342,8 +1346,24 @@ ProxyPass "/" "balancer://mycluster/" stickysession=JSESSIONID|jsessionid nofail </Proxy> +

Configuring hot spares can help ensure that a certain number of + workers are always available for use per load balancer set:

+ +ProxyPass "/" "balancer://sparecluster/" +<Proxy balancer://sparecluster> + BalancerMember ajp://1.2.3.4:8009 + BalancerMember ajp://1.2.3.5:8009 + # The servers below are hot spares. For each server above that is unusable + # (draining, stopped, unreachable, in error state, etc.), one of these spares + # will be used in its place. Two servers will always be available for a request + # unless one or more of the spares is also unusable. + BalancerMember ajp://1.2.3.6:8009 status=+R + BalancerMember ajp://1.2.3.7:8009 status=+R +</Proxy> + +

Setting up a hot-standby that will only be used if no other - members are available:

+ members (or spares) are available in the load balancer set:

ProxyPass "/" "balancer://hotcluster/" <Proxy "balancer://hotcluster"> diff --git a/modules/proxy/balancers/mod_lbmethod_bybusyness.c b/modules/proxy/balancers/mod_lbmethod_bybusyness.c index 30a8f55429..709512bb5e 100644 --- a/modules/proxy/balancers/mod_lbmethod_bybusyness.c +++ b/modules/proxy/balancers/mod_lbmethod_bybusyness.c @@ -22,99 +22,36 @@ module AP_MODULE_DECLARE_DATA lbmethod_bybusyness_module; -static int (*ap_proxy_retry_worker_fn)(const char *proxy_function, - proxy_worker *worker, server_rec *s) = NULL; +static int is_best_bybusyness(proxy_worker *current, proxy_worker *prev_best, void *baton) +{ + int *total_factor = (int *)baton; + + current->s->lbstatus += current->s->lbfactor; + *total_factor += current->s->lbfactor; + + return ( + !prev_best + || (current->s->busy < prev_best->s->busy) + || ( + (current->s->busy == prev_best->s->busy) + && (current->s->lbstatus > prev_best->s->lbstatus) + ) + ); +} static proxy_worker *find_best_bybusyness(proxy_balancer *balancer, - request_rec *r) + request_rec *r) { - int i; - proxy_worker **worker; - proxy_worker *mycandidate = NULL; - int cur_lbset = 0; - int max_lbset = 0; - int checking_standby; - int checked_standby; - int total_factor = 0; + proxy_worker *worker = + ap_proxy_balancer_get_best_worker(balancer, r, is_best_bybusyness, + &total_factor); - if (!ap_proxy_retry_worker_fn) { - ap_proxy_retry_worker_fn = - APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker); - if (!ap_proxy_retry_worker_fn) { - /* can only happen if mod_proxy isn't loaded */ - return NULL; - } - } - - ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01211) - "proxy: Entering bybusyness for BALANCER (%s)", - balancer->s->name); - - /* First try to see if we have available candidate */ - do { - - checking_standby = checked_standby = 0; - while (!mycandidate && !checked_standby) { - - worker = (proxy_worker **)balancer->workers->elts; - for (i = 0; i < balancer->workers->nelts; i++, worker++) { - if (!checking_standby) { /* first time through */ - if ((*worker)->s->lbset > max_lbset) - max_lbset = (*worker)->s->lbset; - } - if ( - ((*worker)->s->lbset != cur_lbset) || - (checking_standby ? !PROXY_WORKER_IS_STANDBY(*worker) : PROXY_WORKER_IS_STANDBY(*worker)) || - (PROXY_WORKER_IS_DRAINING(*worker)) - ) { - continue; - } - - /* If the worker is in error state run - * retry on that worker. It will be marked as - * operational if the retry timeout is elapsed. - * The worker might still be unusable, but we try - * anyway. - */ - if (!PROXY_WORKER_IS_USABLE(*worker)) { - ap_proxy_retry_worker_fn("BALANCER", *worker, r->server); - } - - /* Take into calculation only the workers that are - * not in error state or not disabled. - */ - if (PROXY_WORKER_IS_USABLE(*worker)) { - - (*worker)->s->lbstatus += (*worker)->s->lbfactor; - total_factor += (*worker)->s->lbfactor; - - if (!mycandidate - || (*worker)->s->busy < mycandidate->s->busy - || ((*worker)->s->busy == mycandidate->s->busy && (*worker)->s->lbstatus > mycandidate->s->lbstatus)) - mycandidate = *worker; - - } - - } - - checked_standby = checking_standby++; - - } - - cur_lbset++; - - } while (cur_lbset <= max_lbset && !mycandidate); - - if (mycandidate) { - mycandidate->s->lbstatus -= total_factor; - ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01212) - "proxy: bybusyness selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d", - mycandidate->s->name, mycandidate->s->busy, mycandidate->s->lbstatus); - + if (worker) { + worker->s->lbstatus -= total_factor; } - return mycandidate; + return worker; } /* assumed to be mutex protected by caller */ diff --git a/modules/proxy/balancers/mod_lbmethod_byrequests.c b/modules/proxy/balancers/mod_lbmethod_byrequests.c index 83424cefed..0483a70fec 100644 --- a/modules/proxy/balancers/mod_lbmethod_byrequests.c +++ b/modules/proxy/balancers/mod_lbmethod_byrequests.c @@ -22,8 +22,15 @@ module AP_MODULE_DECLARE_DATA lbmethod_byrequests_module; -static int (*ap_proxy_retry_worker_fn)(const char *proxy_function, - proxy_worker *worker, server_rec *s) = NULL; +static int is_best_byrequests(proxy_worker *current, proxy_worker *prev_best, void *baton) +{ + int *total_factor = (int *)baton; + + current->s->lbstatus += current->s->lbfactor; + *total_factor += current->s->lbfactor; + + return (!prev_best || (current->s->lbstatus > prev_best->s->lbstatus)); +} /* * The idea behind the find_best_byrequests scheduler is the following: @@ -70,82 +77,17 @@ static int (*ap_proxy_retry_worker_fn)(const char *proxy_function, * b a d c d a c d b d ... * */ - static proxy_worker *find_best_byrequests(proxy_balancer *balancer, request_rec *r) { - int i; int total_factor = 0; - proxy_worker **worker; - proxy_worker *mycandidate = NULL; - int cur_lbset = 0; - int max_lbset = 0; - int checking_standby; - int checked_standby; - - if (!ap_proxy_retry_worker_fn) { - ap_proxy_retry_worker_fn = - APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker); - if (!ap_proxy_retry_worker_fn) { - /* can only happen if mod_proxy isn't loaded */ - return NULL; - } - } - - ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01207) - "proxy: Entering byrequests for BALANCER (%s)", - balancer->s->name); - - /* First try to see if we have available candidate */ - do { - checking_standby = checked_standby = 0; - while (!mycandidate && !checked_standby) { - worker = (proxy_worker **)balancer->workers->elts; - for (i = 0; i < balancer->workers->nelts; i++, worker++) { - if (!checking_standby) { /* first time through */ - if ((*worker)->s->lbset > max_lbset) - max_lbset = (*worker)->s->lbset; - } - if ( - ((*worker)->s->lbset != cur_lbset) || - (checking_standby ? !PROXY_WORKER_IS_STANDBY(*worker) : PROXY_WORKER_IS_STANDBY(*worker)) || - (PROXY_WORKER_IS_DRAINING(*worker)) - ) { - continue; - } - - /* If the worker is in error state run - * retry on that worker. It will be marked as - * operational if the retry timeout is elapsed. - * The worker might still be unusable, but we try - * anyway. - */ - if (!PROXY_WORKER_IS_USABLE(*worker)) - ap_proxy_retry_worker_fn("BALANCER", *worker, r->server); - /* Take into calculation only the workers that are - * not in error state or not disabled. - */ - if (PROXY_WORKER_IS_USABLE(*worker)) { - (*worker)->s->lbstatus += (*worker)->s->lbfactor; - total_factor += (*worker)->s->lbfactor; - if (!mycandidate || (*worker)->s->lbstatus > mycandidate->s->lbstatus) - mycandidate = *worker; - } - } - checked_standby = checking_standby++; - } - cur_lbset++; - } while (cur_lbset <= max_lbset && !mycandidate); - - if (mycandidate) { - mycandidate->s->lbstatus -= total_factor; - ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01208) - "proxy: byrequests selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d", - mycandidate->s->name, mycandidate->s->busy, mycandidate->s->lbstatus); + proxy_worker *worker = ap_proxy_balancer_get_best_worker(balancer, r, is_best_byrequests, &total_factor); + if (worker) { + worker->s->lbstatus -= total_factor; } - return mycandidate; + return worker; } /* assumed to be mutex protected by caller */ diff --git a/modules/proxy/balancers/mod_lbmethod_bytraffic.c b/modules/proxy/balancers/mod_lbmethod_bytraffic.c index 6cf2478de5..343c59ac32 100644 --- a/modules/proxy/balancers/mod_lbmethod_bytraffic.c +++ b/modules/proxy/balancers/mod_lbmethod_bytraffic.c @@ -22,8 +22,20 @@ module AP_MODULE_DECLARE_DATA lbmethod_bytraffic_module; -static int (*ap_proxy_retry_worker_fn)(const char *proxy_function, - proxy_worker *worker, server_rec *s) = NULL; +static int is_best_bytraffic(proxy_worker *current, proxy_worker *prev_best, void *baton) +{ + apr_off_t *min_traffic = (apr_off_t *)baton; + apr_off_t traffic = (current->s->transferred / current->s->lbfactor) + + (current->s->read / current->s->lbfactor); + + if (!prev_best || (traffic < *min_traffic)) { + *min_traffic = traffic; + + return TRUE; + } + + return FALSE; +} /* * The idea behind the find_best_bytraffic scheduler is the following: @@ -45,79 +57,10 @@ static int (*ap_proxy_retry_worker_fn)(const char *proxy_function, static proxy_worker *find_best_bytraffic(proxy_balancer *balancer, request_rec *r) { - int i; - apr_off_t mytraffic = 0; - apr_off_t curmin = 0; - proxy_worker **worker; - proxy_worker *mycandidate = NULL; - int cur_lbset = 0; - int max_lbset = 0; - int checking_standby; - int checked_standby; - - if (!ap_proxy_retry_worker_fn) { - ap_proxy_retry_worker_fn = - APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker); - if (!ap_proxy_retry_worker_fn) { - /* can only happen if mod_proxy isn't loaded */ - return NULL; - } - } - - ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01209) - "proxy: Entering bytraffic for BALANCER (%s)", - balancer->s->name); - - /* First try to see if we have available candidate */ - do { - checking_standby = checked_standby = 0; - while (!mycandidate && !checked_standby) { - worker = (proxy_worker **)balancer->workers->elts; - for (i = 0; i < balancer->workers->nelts; i++, worker++) { - if (!checking_standby) { /* first time through */ - if ((*worker)->s->lbset > max_lbset) - max_lbset = (*worker)->s->lbset; - } - if ( - ((*worker)->s->lbset != cur_lbset) || - (checking_standby ? !PROXY_WORKER_IS_STANDBY(*worker) : PROXY_WORKER_IS_STANDBY(*worker)) || - (PROXY_WORKER_IS_DRAINING(*worker)) - ) { - continue; - } - - /* If the worker is in error state run - * retry on that worker. It will be marked as - * operational if the retry timeout is elapsed. - * The worker might still be unusable, but we try - * anyway. - */ - if (!PROXY_WORKER_IS_USABLE(*worker)) - ap_proxy_retry_worker_fn("BALANCER", *worker, r->server); - /* Take into calculation only the workers that are - * not in error state or not disabled. - */ - if (PROXY_WORKER_IS_USABLE(*worker)) { - mytraffic = ((*worker)->s->transferred/(*worker)->s->lbfactor) + - ((*worker)->s->read/(*worker)->s->lbfactor); - if (!mycandidate || mytraffic < curmin) { - mycandidate = *worker; - curmin = mytraffic; - } - } - } - checked_standby = checking_standby++; - } - cur_lbset++; - } while (cur_lbset <= max_lbset && !mycandidate); - - if (mycandidate) { - ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01210) - "proxy: bytraffic selected worker \"%s\" : busy %" APR_SIZE_T_FMT, - mycandidate->s->name, mycandidate->s->busy); - } + apr_off_t min_traffic = 0; - return mycandidate; + return ap_proxy_balancer_get_best_worker(balancer, r, is_best_bytraffic, + &min_traffic); } /* assumed to be mutex protected by caller */ diff --git a/modules/proxy/mod_proxy.c b/modules/proxy/mod_proxy.c index e00a82dffa..bc3410c45a 100644 --- a/modules/proxy/mod_proxy.c +++ b/modules/proxy/mod_proxy.c @@ -68,6 +68,7 @@ proxy_wstat_t PROXY_DECLARE_DATA proxy_wstat_tbl[] = { {PROXY_WORKER_STOPPED, PROXY_WORKER_STOPPED_FLAG, "Stop "}, {PROXY_WORKER_IN_ERROR, PROXY_WORKER_IN_ERROR_FLAG, "Err "}, {PROXY_WORKER_HOT_STANDBY, PROXY_WORKER_HOT_STANDBY_FLAG, "Stby "}, + {PROXY_WORKER_HOT_SPARE, PROXY_WORKER_HOT_SPARE_FLAG, "Spar "}, {PROXY_WORKER_FREE, PROXY_WORKER_FREE_FLAG, "Free "}, {PROXY_WORKER_HC_FAIL, PROXY_WORKER_HC_FAIL_FLAG, "HcFl "}, {0x0, '\0', NULL} diff --git a/modules/proxy/mod_proxy.h b/modules/proxy/mod_proxy.h index bfa5760204..63c2195ffe 100644 --- a/modules/proxy/mod_proxy.h +++ b/modules/proxy/mod_proxy.h @@ -307,6 +307,7 @@ struct proxy_conn_pool { #define PROXY_WORKER_HOT_STANDBY 0x0100 #define PROXY_WORKER_FREE 0x0200 #define PROXY_WORKER_HC_FAIL 0x0400 +#define PROXY_WORKER_HOT_SPARE 0x0800 /* worker status flags */ #define PROXY_WORKER_INITIALIZED_FLAG 'O' @@ -320,6 +321,7 @@ struct proxy_conn_pool { #define PROXY_WORKER_HOT_STANDBY_FLAG 'H' #define PROXY_WORKER_FREE_FLAG 'F' #define PROXY_WORKER_HC_FAIL_FLAG 'C' +#define PROXY_WORKER_HOT_SPARE_FLAG 'R' #define PROXY_WORKER_NOT_USABLE_BITMAP ( PROXY_WORKER_IN_SHUTDOWN | \ PROXY_WORKER_DISABLED | PROXY_WORKER_STOPPED | PROXY_WORKER_IN_ERROR | \ @@ -330,6 +332,8 @@ PROXY_WORKER_HC_FAIL ) #define PROXY_WORKER_IS_STANDBY(f) ( (f)->s->status & PROXY_WORKER_HOT_STANDBY ) +#define PROXY_WORKER_IS_SPARE(f) ( (f)->s->status & PROXY_WORKER_HOT_SPARE ) + #define PROXY_WORKER_IS_USABLE(f) ( ( !( (f)->s->status & PROXY_WORKER_NOT_USABLE_BITMAP) ) && \ PROXY_WORKER_IS_INITIALIZED(f) ) @@ -824,6 +828,23 @@ PROXY_DECLARE(apr_status_t) ap_proxy_initialize_balancer(proxy_balancer *balance server_rec *s, apr_pool_t *p); +typedef int (proxy_is_best_callback_fn_t)(proxy_worker *current, proxy_worker *prev_best, void *baton); + +/** + * Retrieve the best worker in a balancer for the current request + * @param balancer balancer for which to find the best worker + * @param r current request record + * @param is_best a callback function provide by the lbmethod + * that determines if the current worker is best + * @param baton an lbmethod-specific context pointer (baton) + * passed to the is_best callback + * @return the best worker to be used for the request + */ +PROXY_DECLARE(proxy_worker *) ap_proxy_balancer_get_best_worker(proxy_balancer *balancer, + request_rec *r, + proxy_is_best_callback_fn_t *is_best, + void *baton); + /** * Find the shm of the worker as needed * @param storage slotmem provider diff --git a/modules/proxy/mod_proxy_balancer.c b/modules/proxy/mod_proxy_balancer.c index 9605dc04b8..7c12f40316 100644 --- a/modules/proxy/mod_proxy_balancer.c +++ b/modules/proxy/mod_proxy_balancer.c @@ -1237,6 +1237,9 @@ static int balancer_handler(request_rec *r) if ((val = apr_table_get(params, "w_status_H"))) { ap_proxy_set_wstatus(PROXY_WORKER_HOT_STANDBY_FLAG, atoi(val), wsel); } + if ((val = apr_table_get(params, "w_status_R"))) { + ap_proxy_set_wstatus(PROXY_WORKER_HOT_SPARE_FLAG, atoi(val), wsel); + } if ((val = apr_table_get(params, "w_status_S"))) { ap_proxy_set_wstatus(PROXY_WORKER_STOPPED_FLAG, atoi(val), wsel); } @@ -1763,7 +1766,8 @@ static int balancer_handler(request_rec *r) "Ignore Errors" "Draining Mode" "Disabled" - "Hot Standby", r); + "Hot Standby" + "Hot Spare", r); if (hc_show_exprs_f) { ap_rputs("HC Fail", r); } @@ -1772,6 +1776,7 @@ static int balancer_handler(request_rec *r) create_radio("w_status_N", (PROXY_WORKER_IS(wsel, PROXY_WORKER_DRAIN)), r); create_radio("w_status_D", (PROXY_WORKER_IS(wsel, PROXY_WORKER_DISABLED)), r); create_radio("w_status_H", (PROXY_WORKER_IS(wsel, PROXY_WORKER_HOT_STANDBY)), r); + create_radio("w_status_R", (PROXY_WORKER_IS(wsel, PROXY_WORKER_HOT_SPARE)), r); if (hc_show_exprs_f) { create_radio("w_status_C", (PROXY_WORKER_IS(wsel, PROXY_WORKER_HC_FAIL)), r); } diff --git a/modules/proxy/proxy_util.c b/modules/proxy/proxy_util.c index e848d31398..dba06b5678 100644 --- a/modules/proxy/proxy_util.c +++ b/modules/proxy/proxy_util.c @@ -68,6 +68,7 @@ static int proxy_match_ipaddr(struct dirconn_entry *This, request_rec *r); static int proxy_match_domainname(struct dirconn_entry *This, request_rec *r); static int proxy_match_hostname(struct dirconn_entry *This, request_rec *r); static int proxy_match_word(struct dirconn_entry *This, request_rec *r); +static int ap_proxy_retry_worker(const char *proxy_function, proxy_worker *worker, server_rec *s); APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(proxy, PROXY, int, create_req, (request_rec *r, request_rec *pr), (r, pr), @@ -1300,6 +1301,121 @@ PROXY_DECLARE(apr_status_t) ap_proxy_initialize_balancer(proxy_balancer *balance return APR_SUCCESS; } +PROXY_DECLARE(proxy_worker *) ap_proxy_balancer_get_best_worker(proxy_balancer *balancer, + request_rec *r, + proxy_is_best_callback_fn_t *is_best, + void *baton) +{ + int i = 0; + int cur_lbset = 0; + int max_lbset = 0; + int unusable_workers = 0; + apr_pool_t *tpool = NULL; + apr_array_header_t *spares = NULL; + apr_array_header_t *standbys = NULL; + proxy_worker *worker = NULL; + proxy_worker *best_worker = NULL; + + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(10122) + "proxy: Entering %s for BALANCER (%s)", + balancer->lbmethod->name, balancer->s->name); + + apr_pool_create(&tpool, r->pool); + + spares = apr_array_make(tpool, 1, sizeof(proxy_worker*)); + standbys = apr_array_make(tpool, 1, sizeof(proxy_worker*)); + + /* Process lbsets in order, only replacing unusable workers in a given lbset + * with available spares from the same lbset. Hot standbys will be used as a + * last resort when all other workers and spares are unavailable. + */ + for (cur_lbset = 0; !best_worker && (cur_lbset <= max_lbset); cur_lbset++) { + unusable_workers = 0; + apr_array_clear(spares); + apr_array_clear(standbys); + + for (i = 0; i < balancer->workers->nelts; i++) { + worker = APR_ARRAY_IDX(balancer->workers, i, proxy_worker *); + + if (worker->s->lbset > max_lbset) { + max_lbset = worker->s->lbset; + } + + if (worker->s->lbset != cur_lbset) { + continue; + } + + /* A draining worker that is neither a spare nor a standby should be + * considered unusable to be replaced by spares. + */ + if (PROXY_WORKER_IS_DRAINING(worker)) { + if (!PROXY_WORKER_IS_SPARE(worker) && !PROXY_WORKER_IS_STANDBY(worker)) { + unusable_workers++; + } + + continue; + } + + /* If the worker is in error state run retry on that worker. It will + * be marked as operational if the retry timeout is elapsed. The + * worker might still be unusable, but we try anyway. + */ + if (!PROXY_WORKER_IS_USABLE(worker)) { + ap_proxy_retry_worker("BALANCER", worker, r->server); + } + + if (PROXY_WORKER_IS_SPARE(worker)) { + if (PROXY_WORKER_IS_USABLE(worker)) { + APR_ARRAY_PUSH(spares, proxy_worker *) = worker; + } + } + else if (PROXY_WORKER_IS_STANDBY(worker)) { + if (PROXY_WORKER_IS_USABLE(worker)) { + APR_ARRAY_PUSH(standbys, proxy_worker *) = worker; + } + } + else if (PROXY_WORKER_IS_USABLE(worker)) { + if (is_best(worker, best_worker, baton)) { + best_worker = worker; + } + } + else { + unusable_workers++; + } + } + + /* Check if any spares are best. */ + for (i = 0; (i < spares->nelts) && (i < unusable_workers); i++) { + worker = APR_ARRAY_IDX(spares, i, proxy_worker *); + + if (is_best(worker, best_worker, baton)) { + best_worker = worker; + } + } + + /* If no workers are available, use the standbys. */ + if (!best_worker) { + for (i = 0; i < standbys->nelts; i++) { + worker = APR_ARRAY_IDX(standbys, i, proxy_worker *); + + if (is_best(worker, best_worker, baton)) { + best_worker = worker; + } + } + } + } + + apr_pool_destroy(tpool); + + if (best_worker) { + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(10123) + "proxy: %s selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d", + balancer->lbmethod->name, best_worker->s->name, best_worker->s->busy, best_worker->s->lbstatus); + } + + return best_worker; +} + /* * CONNECTION related... */