Add information about upstreams configuration in options.inc (#758)

* Update options.md

* Update upstream.md

* Fix grammar

---------

Co-authored-by: moisseev <[email protected]>

doc/configuration/options.md

@@ -23,6 +23,9 @@ dns {
     sockets = 16;
     retransmits = 5;
 }
+upstream {
+    resolve_min_interval = 60;
+}
 tempdir = "/tmp";
 url_tld = "${PLUGINSDIR}/effective_tld_names.dat";
 classify_headers = [
@@ -199,6 +202,13 @@ neighbours {
 }
 ~~~
 
-## Upstream options
+## Upstreams options
+
+Upstreams logic and settings are described in the dedicated [document]({{ site.baseurl }}/doc/configuration/upstream.html).
+Options for upstreams fall under a dedicated subsection called `upstream` and control their behaviors in Rspamd. Here is a list of available tunables:
 
-See [this document]({{ site.baseurl }}/doc/configuration/upstream.html) for details.
+* `error_time` (defaults to `10`): timeframe to check errors in seconds
+* `max_errors` (defaults to `4`): maximum count of errors during `error_time` to consider the upstream as down
+* `revive_time` (defaults to `60`): count of seconds before attempting to recover upstream after it has faced `max_errors` and has been marked as unhealthy
+* `lazy_resolve_time` (defaults to `3600`, which is 1 hour): time in seconds to resolve upstream addresses in lazy mode
+* `resolve_min_interval` (defaults to `60`): minimum interval in seconds to perform resolving upstream DNS resolution

doc/configuration/upstream.md

@@ -78,8 +78,10 @@ When an upstream reaches the error rate limit, Rspamd marks it as inactive and w
 
 <img class="img-fluid" width="75%" src="{{ site.baseurl }}/img/upstreams.png">
 
+To tune these settings, please see the [Upstream options]({{ site.baseurl }}/doc/configuration/options.html#upstreams-options) documentation.
+
 ## Name resolution
 
-Rspamd treats upstreams defined with their names differently. During the `revive_time`, Rspamd attempts to re-resolve these names and inserts any new IP addresses into the upstream list. If a name has multiple addresses, Rspamd includes all of them. The addresses are then selected using round-robin rotation with error checking. Unlike upstream configurations, errors are persistent and not cleared after successful attempts. Therefore, Rspamd always selects an address with a lower error count. This approach is taken to disable an IPv6 address, for example, if IPv6 is improperly configured in the system.
+Rspamd treats upstreams defined with their names differently. During the `revive_time`, Rspamd attempts to re-resolve these names and inserts any new IP addresses into the upstream list. The minimum interval between resolve attempts is controlled by `resolve_min_interval`, which is by default set to 1 minute. If a name has multiple addresses, Rspamd includes all of them. The addresses are then selected using round-robin rotation with error checking. Unlike upstream configurations, errors are persistent and not cleared after successful attempts. Therefore, Rspamd always selects an address with a lower error count. This approach is taken to disable an IPv6 address, for example, if IPv6 is improperly configured in the system.
 
-Starting from version 2.0, Rspamd also performs background resolution of all upstreams every `lazy_resolve_time` + `jitter(0.1 * lazy_resolve_time)`. By default, this value is set to 1 hour, but you can customize it in the configuration (options -> upstreams section). This allows Rspamd to update its knowledge of upstream IP addresses, ensuring efficient and reliable connections. SRV based upstreams are resolved in two steps: one for SRV record resolution and one for targets resolution.
+Starting from version 2.0, Rspamd also performs background resolution of all upstreams every `lazy_resolve_time` + `jitter(0.1 * lazy_resolve_time)`. By default, this value is set to 1 hour, but you can customize it in the configuration (options -> upstreams section). This allows Rspamd to update its knowledge of upstream IP addresses, ensuring efficient and reliable connections. SRV-based upstreams are resolved in two steps: one for SRV record resolution and one for target resolution.