MEDIUM: server: allow multi-level server tracking
Now that it is possible to know whether a server is in forced maintenance
or inherits its maintenance status from another one, it is possible to
allow server tracking at more than one level. We still provide a loop
detection however.
Note that for the stats it's a bit trickier since we have to report the
check state which corresponds to the state of the server at the end of
the chain.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index a5ec732..b81b78d 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -8999,10 +8999,10 @@
Supported in default-server: No
track [<proxy>/]<server>
- This option enables ability to set the current state of the server by
- tracking another one. Only a server with checks enabled can be tracked
- so it is not possible for example to track a server that tracks another
- one. If <proxy> is omitted the current one is used. If disable-on-404 is
+ This option enables ability to set the current state of the server by tracking
+ another one. It is possible to track a server which itself tracks another
+ server, provided that at the end of the chain, a server has health checks
+ enabled. If <proxy> is omitted the current one is used. If disable-on-404 is
used, it has to be enabled on both proxies.
Supported in default-server: No
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 08168a1..0a32df4 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -6563,7 +6563,7 @@
if (newsrv->trackit) {
struct proxy *px;
- struct server *srv;
+ struct server *srv, *loop;
char *pname, *sname;
pname = newsrv->trackit;
@@ -6597,11 +6597,24 @@
goto next_srv;
}
- if (!(srv->check.state & CHK_ST_CONFIGURED)) {
+ if (!(srv->check.state & CHK_ST_CONFIGURED) &&
+ !(srv->agent.state & CHK_ST_CONFIGURED) &&
+ !srv->track && !srv->trackit) {
Alert("config : %s '%s', server '%s': unable to use %s/%s for "
- "tracking as it does not have checks enabled.\n",
- proxy_type_str(curproxy), curproxy->id,
- newsrv->id, px->id, srv->id);
+ "tracking as it does not have any check nor agent enabled.\n",
+ proxy_type_str(curproxy), curproxy->id,
+ newsrv->id, px->id, srv->id);
+ cfgerr++;
+ goto next_srv;
+ }
+
+ for (loop = srv->track; loop && loop != newsrv; loop = loop->track);
+
+ if (loop) {
+ Alert("config : %s '%s', server '%s': unable to track %s/%s as it "
+ "belongs to a tracking chain looping back to %s/%s.\n",
+ proxy_type_str(curproxy), curproxy->id,
+ newsrv->id, px->id, srv->id, px->id, loop->id);
cfgerr++;
goto next_srv;
}
diff --git a/src/dumpstats.c b/src/dumpstats.c
index d0cd632..4d56e25 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -2737,11 +2737,19 @@
static int stats_dump_sv_stats(struct stream_interface *si, struct proxy *px, int flags, struct server *sv, int state)
{
struct appctx *appctx = __objt_appctx(si->end);
- struct server *ref = sv->track ? sv->track : sv;
+ struct server *via, *ref;
char str[INET6_ADDRSTRLEN];
struct chunk src;
int i;
+ /* we have "via" which is the tracked server as described in the configuration,
+ * and "ref" which is the checked server and the end of the chain.
+ */
+ via = sv->track ? sv->track : sv;
+ ref = via;
+ while (ref->track)
+ ref = ref->track;
+
if (appctx->ctx.stats.flags & STAT_FMT_HTML) {
static char *srv_hlt_st[9] = {
"DOWN",
@@ -2950,7 +2958,7 @@
/* tracking a server */
chunk_appendf(&trash,
"<td class=ac colspan=3><a class=lfsb href=\"#%s/%s\">via %s/%s</a></td>",
- ref->proxy->id, ref->id, ref->proxy->id, ref->id);
+ via->proxy->id, via->id, via->proxy->id, via->id);
}
else
chunk_appendf(&trash, "<td colspan=3></td>");
@@ -3000,7 +3008,7 @@
/* status */
if (sv->admin & SRV_ADMF_IMAINT)
- chunk_appendf(&trash, "MAINT (via %s/%s),", ref->proxy->id, ref->id);
+ chunk_appendf(&trash, "MAINT (via %s/%s),", via->proxy->id, via->id);
else if (sv->admin & SRV_ADMF_MAINT)
chunk_appendf(&trash, "MAINT,");
else
@@ -3582,10 +3590,9 @@
continue;
}
- if (sv->track)
- svs = sv->track;
- else
- svs = sv;
+ svs = sv;
+ while (svs->track)
+ svs = svs->track;
/* FIXME: produce some small strings for "UP/DOWN x/y &#xxxx;" */
if (!(svs->check.state & CHK_ST_ENABLED))
diff --git a/src/server.c b/src/server.c
index f0fb0a7..53e20bf 100644
--- a/src/server.c
+++ b/src/server.c
@@ -359,12 +359,16 @@
check->health = check->rise; /* start OK but check immediately */
}
+ srv = s;
+ while (srv->track)
+ srv = srv->track;
+
if ((!s->track &&
(!(s->agent.state & CHK_ST_ENABLED) || (s->agent.health >= s->agent.rise)) &&
(!(s->check.state & CHK_ST_ENABLED) || (s->check.health >= s->check.rise))) ||
(s->track &&
- (!(s->track->agent.state & CHK_ST_ENABLED) || (s->track->agent.health >= s->track->agent.rise)) &&
- (!(s->track->check.state & CHK_ST_ENABLED) || (s->track->check.health >= s->track->check.rise)))) {
+ (!(srv->agent.state & CHK_ST_ENABLED) || (srv->agent.health >= srv->agent.rise)) &&
+ (!(srv->check.state & CHK_ST_ENABLED) || (srv->check.health >= srv->check.rise)))) {
if (s->proxy->srv_bck == 0 && s->proxy->srv_act == 0) {
if (s->proxy->last_change < now.tv_sec) // ignore negative times