add reference to process resource registry

docs/attributes-registry/linux.md

@@ -32,4 +32,4 @@ Describes Linux Process attributes
 |---|---|---|---|---|
 | <a id="linux-process-cgroup" href="#linux-process-cgroup">`linux.process.cgroup`</a> | string | The control group associated with the process. [1] | `1:name=systemd:/user.slice/user-1000.slice/session-3.scope`; `0::/user.slice/user-1000.slice/[email protected]/tmux-spawn-0267755b-4639-4a27-90ed-f19f88e53748.scope` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 
-**[1]:** Control groups (cgroups) are a kernel feature used to organize and manage process resources. This attribute provides the path(s) to the cgroup(s) associated with the process, which should match the contents of the [/proc/<PID>/cgroup](https://man7.org/linux/man-pages/man7/cgroups.7.html) file.
+**[1] `linux.process.cgroup`:** Control groups (cgroups) are a kernel feature used to organize and manage process resources. This attribute provides the path(s) to the cgroup(s) associated with the process, which should match the contents of the [/proc/<PID>/cgroup](https://man7.org/linux/man-pages/man7/cgroups.7.html) file.

docs/resource/process.md

@@ -42,6 +42,7 @@
 | [`process.command_line`](/docs/attributes-registry/process.md) | string | The full command used to launch the process as a single string representing the full command. On Windows, can be set to the result of `GetCommandLineW`. Do not set this if you have to assemble it just for monitoring; use `process.command_args` instead. | `C:\cmd\otecol --config="my directory\config.yaml"` | `Conditionally Required` [3] | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 | [`process.executable.name`](/docs/attributes-registry/process.md) | string | The name of the process executable. On Linux based systems, can be set to the `Name` in `proc/[pid]/status`. On Windows, can be set to the base name of `GetProcessImageFileNameW`. | `otelcol` | `Conditionally Required` [4] | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 | [`process.executable.path`](/docs/attributes-registry/process.md) | string | The full path to the process executable. On Linux based systems, can be set to the target of `proc/[pid]/exe`. On Windows, can be set to the result of `GetProcessImageFileNameW`. | `/usr/bin/cmd/otelcol` | `Conditionally Required` [5] | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| [`linux.process.cgroup`](/docs/attributes-registry/linux.md) | string | The control group associated with the process. [6] | `1:name=systemd:/user.slice/user-1000.slice/session-3.scope`; `0::/user.slice/user-1000.slice/[email protected]/tmux-spawn-0267755b-4639-4a27-90ed-f19f88e53748.scope` | `Recommended` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 | [`process.owner`](/docs/attributes-registry/process.md) | string | The username of the user that owns the process. | `root` | `Recommended` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 | [`process.parent_pid`](/docs/attributes-registry/process.md) | int | Parent Process identifier (PPID). | `111` | `Recommended` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 | [`process.pid`](/docs/attributes-registry/process.md) | int | Process identifier (PID). | `1234` | `Recommended` | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
@@ -56,6 +57,8 @@
 
 **[5] `process.executable.path`:** See [Selecting process attributes](#selecting-process-attributes) for details.
 
+**[6] `linux.process.cgroup`:** Control groups (cgroups) are a kernel feature used to organize and manage process resources. This attribute provides the path(s) to the cgroup(s) associated with the process, which should match the contents of the [/proc/<PID>/cgroup](https://man7.org/linux/man-pages/man7/cgroups.7.html) file.
+
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model/process/resources.yaml

@@ -23,6 +23,7 @@ groups:
         requirement_level:
           conditionally_required: See [Selecting process attributes](#selecting-process-attributes) for details.
       - ref: process.owner
+      - ref: linux.process.cgroup
 
   - id: resource.process.runtime
     type: resource