Add documentation for jolokia autodiscover

CHANGELOG.asciidoc

@@ -143,6 +143,7 @@ https://github.com/elastic/beats/compare/v6.2.3...master[Check the HEAD diff]
 - Add support for loading a template.json file directly instead of using fields.yml. {pull}7039[7039]
 - Add support for keyword multifields in field.yml. {pull}7131[7131]
 - Add dissect processor. {pull}6925[6925]
+- Add experimental Jolokia Discovery autodiscover provider. {pull}7141[7141]
 
 *Auditbeat*
 

filebeat/docs/autodiscover-jolokia-config.asciidoc

@@ -0,0 +1,23 @@
+Filebeat supports templates for inputs and modules:
+
+["source","yaml",subs="attributes"]
+-------------------------------------------------------------------------------
+filebeat.autodiscover:
+  providers:
+    - type: jolokia
+      interfaces:
+      - name: lo
+      templates:
+      - condition:
+          contains:
+            jolokia.server.product: "kafka"
+        config:
+        - module: kafka
+          log:
+            enabled: true
+            var.paths:
+            - /var/log/kafka/*.log
+-------------------------------------------------------------------------------
+
+This configuration starts a jolokia module that collects logs of kafka if it is
+running. Discovery probes are sent using the local interface.

libbeat/autodiscover/providers/jolokia/discovery.go

@@ -64,7 +64,6 @@ type Event struct {
 func (e *Event) BusEvent() bus.Event {
 	event := bus.Event{
 		e.Type:    true,
-		"host":    e.Message["url"],
 		"jolokia": e.Message,
 		"meta": common.MapStr{
 			"jolokia": e.Message,

libbeat/docs/shared-autodiscover.asciidoc

@@ -114,6 +114,57 @@ contain variables from the autodiscover event. They can be accessed under data n
 
 include::../../{beatname_lc}/docs/autodiscover-kubernetes-config.asciidoc[]
 
+[float]
+===== Jolokia (experimental)
+
+The Jolokia autodiscover provider uses Jolokia Discovery to find agents running
+in your host or your network.
+
+Jolokia Discovery mechanism is supported by any Jolokia agent since version
+1.2.0, it is enabled by default when Jolokia is included in the application as
+a JVM agent, but disabled in other cases as the OSGI or WAR (Java EE) agents.
+In any case, this feature is controlled with two properties:
+
+  * `discoveryEnabled`, to enable the feature
+  * `discoveryAgentUrl`, if set, this is the URL announced by the agent when
+    being discovered, setting this parameter implicitely enables the feature
+
+There are multiple ways of setting these properties, and they can vary from
+application to application, please refer to the documentation of your
+application to find the more suitable way to set them in your case.
+
+Jolokia Discovery is based on UDP multicast requests. Agents join the multicast
+group 239.192.48.84, port 24884, and discovery is done by sending queries to
+this group. You have to take into account that UDP traffic between Metricbeat
+and the Jolokia agents has to be allowed. Also notice that this multicast
+address is in the 239.0.0.0/8 range, that is reserved for private use within an
+organization, so it can only be used in private networks.
+
+These are the available fields on every event:
+
+  * jolokia.agent.id
+  * jolokia.agent.version
+  * jolokia.secured
+  * jolokia.server.product
+  * jolokia.server.vendor
+  * jolokia.server.version
+  * jolokia.url
+
+The configuration of this provider consists in a set of network interfaces, as
+well as a set of templates as in other providers. The network interfaces will be
+the ones used for discovery probes, they have these settings:
+
+  * `name`: the name of the interface (e.g. `br0`), it can contain a wildcard
+    at as suffix to apply the same settings to multiple network interfaces of
+    the same type (e.g. `br*`).
+  * `interval`: time between probes (defaults to 10s)
+  * `grace_period`: time since the last reply to consider a instance stopped
+    (defaults to 30s)
+  * `probe_timeout`: max time to wait for responses since a probe is sent
+    (defaults to 1s)
+
+include::../../{beatname_lc}/docs/autodiscover-jolokia-config.asciidoc[]
+
 [[configuration-autodiscover-hints]]
 === Hints based autodiscover
 

metricbeat/docs/autodiscover-jolokia-config.asciidoc

@@ -0,0 +1,32 @@
+Metricbeat supports templates for modules:
+
+["source","yaml",subs="attributes"]
+-------------------------------------------------------------------------------
+metricbeat.autodiscover:
+  providers:
+    - type: jolokia
+      interfaces:
+      - name: br*
+        interval: 5s
+        grace_period: 10s
+      - name: en*
+      templates:
+      - condition:
+          contains:
+            jolokia.server.product: "tomcat"
+        config:
+        - module: jolokia
+          metricsets: ["jmx"]
+          hosts: "${data.jolokia.url}"
+          namespace: test
+          jmx.mappings:
+          - mbean: "java.lang:type=Runtime"
+            attributes:
+            - attr: Uptime
+              field: uptime
+-------------------------------------------------------------------------------
+
+This configuration starts a jolokia module that collects the uptime of each
+`tomcat` instance discovered. Discovery probes are sent using all interfaces
+starting with `br` and `en`, for the `br` interfaces the `interval` and
+`grace_period` is reduced to 5 and 10 seconds respectively.