Update README.md (#17402)

This adds the Helm configuration for systemd, which can be made available for customers via a new 'Helm' tab.

Author: joshhayles

systemd/README.md

@@ -44,6 +44,37 @@ docker run -d -v /var/run/docker.sock:/var/run/docker.sock:ro \
  datadog/agent:latest
 ```
 
+#### Helm
+
+For Helm configurations, you can set up the Datadog Agent to monitor systemd units (such as: `kubelet.service` and `ssh.service`) by defining volume mounts and volumes for accessing systemd-related files and directories within containers. For example:
+
+```bash
+datadog:
+ #(...)
+ confd: 
+ # Custom config file for SystemD
+ # Example: https://github.com/DataDog/datadog-agent/blob/main/cmd/agent/dist/conf.d/systemd.d/conf.yaml.example
+ 
+ systemd.yaml: |-
+ init_config:
+ instances:
+ - unit_names:
+ - kubelet.service
+ - ssh.service
+ 
+agents:
+ # Custom Mounts for SystemD socket (/run/systemd/private)
+ volumeMounts:
+ - name: systemd
+ mountPath: /host/run/systemd/ # the path within the container where the volume will be mounted
+ 
+ volumes:
+ - name: systemd
+ hostPath:
+ path: /run/systemd/ # the path on the host machine that will be mounted into the container.
+```
+
+
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