[MEDIUM] stats: add the "set weight" command
It is now possible to change a server's weight from the stats socket.
Just use "set weight <back>/<serv> <weight>".
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 82b73b3..276f660 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -6876,6 +6876,20 @@
the one that appears in the configuration file. Both are normally equal
unless the current weight has been changed.
+set weight <backend>/<server> <weight>[%]
+ Change a server's weight to the value passed in argument. If the value ends
+ with the '%' sign, then the new weight will be relative to the initially
+ configured weight. Relative weights are only permitted between 0 and 100%,
+ and absolute weights are permitted between 0 and 256. Servers which are part
+ of a farm running a static load-balancing algorithm have stricter limitations
+ because the weight cannot change once set. Thus for these servers, the only
+ accepted values are 0 and 100% (or 0 and the initial weight). Changes take
+ effect immediately, though certain LB algorithms require a certain amount of
+ requests to consider changes. A typical usage of this command is to disable
+ a server during an update by setting its weight to zero, then to enable it
+ again after the update by setting it back to 100%. This command is restricted
+ and can only be issued on sockets configured for level "admin".
+
/*
* Local variables:
diff --git a/src/dumpstats.c b/src/dumpstats.c
index e576b12..5275dae 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -63,6 +63,7 @@
" show errors : report last request and response errors for each proxy\n"
" show sess : report the list of current sessions\n"
" get weight : report a server's current weight\n"
+ " set weight : change a server's weight\n"
"";
const char stats_permission_denied_msg[] =
@@ -412,7 +413,88 @@
return 0;
}
}
- else { /* not "show" nor "clear" nor "get" */
+ else if (strcmp(args[0], "set") == 0) {
+ if (strcmp(args[1], "weight") == 0) {
+ struct proxy *px;
+ struct server *sv;
+ int w;
+
+ if (s->listener->perm.ux.level < ACCESS_LVL_ADMIN) {
+ buffer_feed(si->ib, stats_permission_denied_msg);
+ return 1;
+ }
+
+ /* split "backend/server" and make <line> point to server */
+ for (line = args[2]; *line; line++)
+ if (*line == '/') {
+ *line++ = '\0';
+ break;
+ }
+
+ if (!*line || !*args[3]) {
+ buffer_feed(si->ib, "Require 'backend/server' and 'weight' or 'weight%'.\n");
+ return 1;
+ }
+
+ if (!get_backend_server(args[2], line, &px, &sv)) {
+ if (!px)
+ buffer_feed(si->ib, "No such backend.\n");
+ else
+ buffer_feed(si->ib, "No such server.\n");
+ return 1;
+ }
+
+ /* if the weight is terminated with '%', it is set relative to
+ * the initial weight, otherwise it is absolute.
+ */
+ w = atoi(args[3]);
+ if (strchr(args[3], '%') != NULL) {
+ if (w < 0 || w > 100) {
+ buffer_feed(si->ib, "Relative weight can only be set between 0 and 100% inclusive.\n");
+ return 1;
+ }
+ w = sv->iweight * w / 100;
+ }
+ else {
+ if (w < 0 || w > 256) {
+ buffer_feed(si->ib, "Absolute weight can only be between 0 and 256 inclusive.\n");
+ return 1;
+ }
+ }
+
+ if (w && w != sv->iweight && !(px->lbprm.algo & BE_LB_PROP_DYN)) {
+ buffer_feed(si->ib, "Backend is using a static LB algorithm and only accepts weights '0%' and '100%'.\n");
+ return 1;
+ }
+
+ sv->uweight = w;
+
+ if (px->lbprm.algo & BE_LB_PROP_DYN) {
+ /* we must take care of not pushing the server to full throttle during slow starts */
+ if ((sv->state & SRV_WARMINGUP) && (px->lbprm.algo & BE_LB_PROP_DYN))
+ sv->eweight = (BE_WEIGHT_SCALE * (now.tv_sec - sv->last_change) + sv->slowstart - 1) / sv->slowstart;
+ else
+ sv->eweight = BE_WEIGHT_SCALE;
+ sv->eweight *= sv->uweight;
+ } else {
+ sv->eweight = sv->uweight;
+ }
+
+ /* static LB algorithms are a bit harder to update */
+ if (px->lbprm.update_server_eweight)
+ px->lbprm.update_server_eweight(sv);
+ else if (sv->eweight)
+ px->lbprm.set_server_status_up(sv);
+ else
+ px->lbprm.set_server_status_down(sv);
+
+ return 1;
+ }
+ else { /* not "set weight" */
+ return 0;
+ }
+ }
+ else { /* not "show" nor "clear" nor "get" nor "set" */
return 0;
}
return 1;