Add hints based autodiscover part

docs/en/ingest-management/elastic-agent/configuration/providers/kubernetes-provider.asciidoc

@@ -224,7 +224,7 @@ In addition, the Kubernetes metadata are being added to each event by default.
 
 
 [discrete]
-== Autodiscover target Pods
+== Autodiscover targeted Pods
 
 To set the target host dynamically only for a targeted Pod based on its labels, use a variable in the
 {agent} policy to return path information from the provider:
@@ -331,6 +331,81 @@ The policy generated by this configuration looks like:
         target: orchestrator
 ----
 
+[discrete]
+== Autodiscover targeted Pods using hints (Elastic Agent standalone mode)
+
+Standalone Elastic Agent supports autodiscover based on hints from the provider.
+The hints mechanism looks for hints in Kubernetes Pod annotations which have the prefix `co.elastic.hints`.
+As soon as the container starts, Elastic Agent will check if it contains any hints and launch the proper config for it.
+Hints tell Elastic Agent how to monitor the given container by using the proper integration.
+This is the full list of supported hints:
+
+[float]
+===== `co.elastic.hints/package`
+
+The package to use for monitoring.
+
+[float]
+===== `co.elastic.hints/data_stream`
+
+(optional) The list of data_streams to enable. If not specified the default data_streams will be enabled using the
+default values as specified in the respective package/integration.
+
+If data_streams are specified, then hints can be defined per data_stream like `co.elastic.hints/key.period: 10m`,
+otherwise the data_stream will use the top level hints (`co.elastic.hints/period: 10m`) in its configuration.
+
+[float]
+===== `co.elastic.hints/host`
+
+The host to use for metrics retrieval.
+
+[float]
+===== `co.elastic.hints/metrics_path`
+
+The path to retrieve the metrics from (/metrics by default).
+
+[float]
+===== `co.elastic.hints/period`
+
+The time interval for metrics retrieval, ie: 10s
+
+[float]
+===== `co.elastic.hints/timeout`
+
+Metrics retrieval timeout, default: 3s
+
+[float]
+===== `co.elastic.hints/username`
+
+The username to use for authentication
+
+[float]
+===== `co.elastic.hints/password`
+
+The password to use for authentication. It is recommended to retrieve this sensitive information from an ENV variable
+and avoid placing passwords in plain text.
+
+[float]
+===== `co.elastic.hints/stream`
+
+The stream to use for logs collection, ie stdout/stderr.
+
+In any case if the specified package has no logs support a generic container's logs input will be used as a
+fallback.
+
+In order to enable hints one need to add the `hints.enabled: true` in the provider's configuration, ie:
+
+[source,yaml]
+----
+providers:
+  kubernetes:
+    node: ${NODE_NAME}
+    hints.enabled: true
+----
+
+The available packages that are supported through hints can be found at
+https://github.com/elastic/elastic-agent/tree/main/deploy/kubernetes/elastic-agent-standalone/templates.d
+
 [discrete]
 == Provider for Node resources
 

docs/en/ingest-management/elastic-agent/running-on-kubernetes-standalone.asciidoc

@@ -259,6 +259,58 @@ the following configuration should be added as an extra input in the DaemonSet m
 Refer to <<kubernetes-provider,dynamic inputs and Kubernetes provider>> for more information
 about shaping dynamic inputs for autodiscovery.
 
+[discrete]
+== Autodiscover targeted Pods using hints
+
+In order to achieve dynamic monitoring of Pods/containers, one can use hints. This can be achieved by properly
+enabling hints for the `kubernetes` dynamic provider. For more information about this feature refer to
+<<kubernetes-provider,dynamic inputs and Kubernetes provider>>.
+
+In the standalone policy ensure that the feature is enabled:
+
+In order to enable hints one need to add the `hints.enabled: true` in the provider's configuration, ie:
+
+[source,yaml]
+----
+providers:
+  kubernetes:
+    node: ${NODE_NAME}
+    hints.enabled: true
+----
+
+Then ensure that the proper volumes and volumeMounts are added properly. These sections are already defined in the
+provided kubernetes manifest, so it's only required to uncomment these sections.
+
+[source,yaml]
+----
+volumeMounts:
+- name: external-inputs
+  mountPath: /etc/elastic-agent/inputs.d
+...
+volumes:
+- name: external-inputs
+  emptyDir: {}
+...
+----
+
+Along with these sections an init container is required which is responsible for downloading the hints' templates.
+The init container is already defined, so uncomment the respective section:
+
+["source", "yaml", subs="attributes"]
+----
+initContainers:
+- name: k8s-templates-downloader
+  image: busybox:1.28
+  command: ['sh']
+  args:
+    - -c
+    - >-
+      mkdir -p /etc/elastic-agent/inputs.d &&
+      wget -O - https://github.com/elastic/elastic-agent/archive/{branch}.tar.gz | tar xz -C /etc/elastic-agent/inputs.d --strip=5 "elastic-agent-main/deploy/kubernetes/elastic-agent-standalone/templates.d"
+  volumeMounts:
+    - name: external-inputs
+      mountPath: /etc/elastic-agent/inputs.d
+----
 
 [discrete]
 == Deploying {agent} to collect cluster-level metrics in large clusters