Amend allowed_attributes in network documentation (#683)

* Amend allowed_attributes in network documentation

* Fix vale errors

docs/sources/network/_index.md

@@ -27,7 +27,9 @@ To get started using Beyla networking metrics, consult the [quickstart setup doc
 
 ## Metric attributes
 
-Network metrics provides a single **OpenTelemetry** metric `beyla.network.flow.bytes`, a counter of Number of bytes observed between two network endpoints, with the following attributes:
+Network metrics provides a single **OpenTelemetry** metric `beyla.network.flow.bytes`, a counter of Number of bytes observed between two network endpoints, and can have the attributes in the following table.
+
+By default, only the following attributes are reported: `k8s.src.owner.name`, `k8s.src.namespace`, `k8s.dst.owner.name`, `k8s.dst.namespace`, and `k8s.cluster.name`.
 
 | Attribute name       | Description                                                                                                                                                                         |
 |----------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
@@ -36,8 +38,6 @@ Network metrics provides a single **OpenTelemetry** metric `beyla.network.flow.b
 | `dst.address`        | Destination IP address of Network flow                                                                                                                                              |
 | `src.name`           | Name of Network flow source: Kubernetes name, host name, or IP address                                                                                                              |
 | `dst.name`           | Name of Network flow destination: Kubernetes name, host name, or IP address                                                                                                         |
-| `src.namespace`      | Namespace of Network flow source. Could be empty in non-Kubernetes flows                                                                                                            |
-| `dst.namespace`      | Namespace of Network flow destination. Could be empty in non-Kubernetes flows                                                                                                       |
 | `src.cidr`           | If the [`cidrs` configuration section]({{< relref "./config" >}}) is set, the CIDR that matches the source IP address                                                               |
 | `dst.cidr`           | If the [`cidrs` configuration section]({{< relref "./config" >}}) is set, the CIDR that matches the destination IP address                                                          |
 | `k8s.src.namespace`  | Kubernetes namespace of the source of the flow                                                                                                                                      |
@@ -54,11 +54,13 @@ Network metrics provides a single **OpenTelemetry** metric `beyla.network.flow.b
 | `k8s.dst.node.name`  | Name of the destination Node                                                                                                                                                        |
 | `k8s.cluster.name`   | Name of the Kubernetes cluster. Beyla can auto-detect it on Google Cloud, Microsoft Azure, and Amazon Web Services. For other providers, set the `BEYLA_KUBE_CLUSTER_NAME` property |
 
-### Allowed attributes
+### How to specify reported attributes
+
+If the metric with all the possible attributes is reported it might lead to a cardinality explosion, especially when including external traffic in the `src.address`/`dst.address` attributes.
 
-If the metric with all the attributes is reported it might lead to a cardinality explosion, especially when including external traffic in the `src.address`/`dst.address` attributes.
+You can specify which attributes are allowed in the Beyla configuration, to aggregate the metric by them.
 
-You can specify which attributes are allowed in the Beyla configuration. Allowed attributes and aggregates the metrics by them. For example:
+For example:
 
 ```yaml
 network:
@@ -68,6 +70,7 @@ network:
     - k8s.src.namespace
     - k8s.dst.owner.name
     - k8s.dst.namespace
+    - k8s.cluster.name
 ```
 
 In this example, the bytes metric is the aggregated by the source and destination owners. This is, all the

docs/sources/network/config.md

@@ -43,23 +43,23 @@ network:
 
 Enables network metrics reporting in Beyla.
 
-| YAML                 | Environment variable               | Type     | Default |
-| -------------------- | ---------------------------------- | -------- | ------- |
-| `allowed_attributes` | `BEYLA_NETWORK_ALLOWED_ATTRIBUTES` | []string | (empty) |
+| YAML                 | Environment variable               | Type     | Default                                                                                                  |
+| -------------------- | ---------------------------------- | -------- | -------------------------------------------------------------------------------------------------------- |
+| `allowed_attributes` | `BEYLA_NETWORK_ALLOWED_ATTRIBUTES` | []string | `k8s.src.owner.name`, `k8s.src.namespace`, `k8s.dst.owner.name`, `k8s.dst.namespace`, `k8s.cluster.name` |
 
 Specifies which attributes are visible in the metrics.
 Beyla aggregates the metrics by their common visible attributes.
 For example, hiding the `k8s.src.name` and allowing `k8s.src.owner.name` would aggregate the metrics of all the pods under the same owner.
 
 This property won't filter some meta-attributes such as `instance`, `job`, `service.instance.id`, `service_name`, `telemetry.sdk.*`, etc.
 
+See the [network metrics documentation]({{< relref "./_index.md" >}}) for a detailed list of all the available attributes.
+
 {{% admonition type="note" %}}
-If left empty, Beyla reports all attributes; which might greatly increase the cardinality of your metrics.
+Select carefully the reported attributes, as some attributes might greatly increase the cardinality of your metrics.
 Setting this value to list only the attributes you really need is highly recommended.
 {{% /admonition %}}
 
-See the [network metrics documentation]({{< relref "./_index.md" >}}) for a detailed list of all the available attributes.
-
 If you set this property via environment variable each entry must be separated by a comma, for example:
 
 ```sh

docs/sources/network/quickstart.md

@@ -146,8 +146,7 @@ Use `kubectl logs` to see network flow entries, for example:
 
 ```
 network_flow: beyla.ip=172.18.0.2 iface= direction=255 src.address=10.244.0.4 dst.address=10.96.0.1
-src.name=local-path-provisioner-7577fdbbfb-g6b7d src.namespace=local-path-storage
-dst.name=kubernetes dst.namespace=default k8s.src.node.ip=172.18.0.2
+src.name=local-path-provisioner-7577fdbbfb-g6b7d dst.name=kubernetes
 k8s.src.node.name=kind-control-plane k8s.dst.namespace=default k8s.dst.name=kubernetes
 k8s.dst.owner.type=Service k8s.src.namespace=local-path-storage
 k8s.src.name=local-path-provisioner-7577fdbbfb-g6b7d k8s.src.type=Pod
@@ -209,14 +208,20 @@ Also Add `OTEL_EXPORTER_OTLP_ENDPOINT` and its value as an environment variable
 
 ## Select metrics attributes to reduce cardinality
 
-Letting Beyla to include all the [attributes]({{< relref "./_index.md" >}}) in the reported metric might lead to
-a [cardinality explosion](/blog/2022/02/15/what-are-cardinality-spikes-and-why-do-they-matter/) in
-your metrics storage, especially if you are capturing external traffic and reporting their IP addresses in the
-`src.address` or `dst.address` metric attribute.
+Be default, Beyla includes the following [attributes]({{< relref "./_index.md" >}}) in the `beyla.network.flow.bytes` metric:
+
+- `k8s.src.owner.name`
+- `k8s.src.namespace`
+- `k8s.dst.owner.name`
+- `k8s.dst.namespace`
+- `k8s.cluster.name`
 
+Beyla only includes a subset of the available attributes to avoid leading to
+a [cardinality explosion](/blog/2022/02/15/what-are-cardinality-spikes-and-why-do-they-matter/) in
+the metrics storage, especially if some attributes like `src.address` or `dst.address` capture the IP addresses of the external traffic.
 
 The `allowed_attributes` YAML subsection under `network` (or the `BEYLA_NETWORK_ALLOWED_ATTRIBUTES` environment variable)
-lets you selecting the attributes to report:
+lets to select the attributes to report:
 
 ```yaml
 network: