docs: add "For Netdata running in a Docker container" to go.d/smartcl (#17980)

packaging/docker/README.md

@@ -372,6 +372,8 @@ to Caddyfile.
 
 ### With Docker socket proxy
 
+> **Note**: Using Netdata with a Docker socket proxy might have some features not working as expected. It hasn't been fully tested by the Netdata team.
+
 Deploy a Docker socket proxy that accepts and filters out requests using something like
 [HAProxy](/docs/netdata-agent/configuration/running-the-netdata-agent-behind-a-reverse-proxy/Running-behind-haproxy.md) or
 [CetusGuard](https://github.com/hectorm/cetusguard) so that it restricts connections to read-only access to

src/go/collectors/go.d.plugin/modules/smartctl/metadata.yaml

@@ -52,6 +52,32 @@ modules:
           - title: Install smartmontools (v7.0+)
             description: |
               Install `smartmontools` version 7.0 or later using your distribution's package manager. Version 7.0 introduced the `--json` output mode, which is required for this collector to function properly.
+          - title: For Netdata running in a Docker container
+            description: |
+              Netdata requires the `SYS_RAWIO` capability and access to the storage devices to run the `smartctl` collector inside a Docker container. Here's how you can achieve this:
+
+              - `docker run`
+
+                ```bash
+                docker run --cap-add SYS_RAWIO --device /dev/sda:/dev/sda ...
+                ```
+
+              - `docker-compose.yml`
+
+                ```yaml
+                services:
+                  netdata:
+                    cap_add:
+                      - SYS_PTRACE
+                      - SYS_ADMIN
+                      - SYS_RAWIO # smartctl
+                    devices:
+                      - "/dev/sda:/dev/sda"
+                ```
+
+              > **Multiple Devices**: These examples only show mapping of one device (/dev/sda). You'll need to add additional `--device` options (in docker run) or entries in the `devices` list (in docker-compose.yml) for each storage device you want Netdata's smartctl collector to monitor.
+
+              > **NVMe Devices**: Do not map NVMe devices using this method. Netdata uses a [dedicated collector](https://github.com/netdata/netdata/tree/master/src/go/collectors/go.d.plugin/modules/nvme#readme) to monitor NVMe devices.
       configuration:
         file:
           name: go.d/smartctl.conf