docs: add cgroup memory troubleshooting to install doc (coder#16920)

originally thought this fit under [Unofficial Install
Methods](https://coder.com/docs/install/other), but we don't talk about
Raspberry Pi anywhere, so ~the general Install doc might be a better
fit~ moved to admin>templates>troubleshooting


[preview](https://coder.com/docs/@3-cgroup-mem/admin/templates/troubleshooting#coder-on-raspberry-pi-os)

---------

Co-authored-by: EdwardAngert <17991901+EdwardAngert@users.noreply.github.com>
Co-authored-by: M Atif Ali <atif@coder.com>

Author: EdwardAngert

docs/admin/templates/troubleshooting.md

@@ -170,3 +170,59 @@ See our
 to optimize your templates based on this data.
 
 ![Workspace build timings UI](../../images/admin/templates/troubleshooting/workspace-build-timings-ui.png)
+
+## Docker Workspaces on Raspberry Pi OS
+
+### Unable to query ContainerMemory
+
+When you query `ContainerMemory` and encounter the error:
+
+```shell
+open /sys/fs/cgroup/memory.max: no such file or directory
+```
+
+This error mostly affects Raspberry Pi OS, but might also affect older Debian-based systems as well.
+
+<details><summary>Add cgroup_memory and cgroup_enable to cmdline.txt:</summary>
+
+1. Confirm the list of existing cgroup controllers doesn't include `memory`:
+
+   ```console
+   $ cat /sys/fs/cgroup/cgroup.controllers
+   cpuset cpu io pids
+
+   $ cat /sys/fs/cgroup/cgroup.subtree_control
+   cpuset cpu io pids
+   ```
+
+1. Add cgroup entries to `cmdline.txt` in `/boot/firmware` (or `/boot/` on older Pi OS releases):
+
+   ```text
+   cgroup_memory=1 cgroup_enable=memory
+   ```
+
+   You can use `sed` to add it to the file for you:
+
+   ```bash
+   sudo sed -i '$s/$/ cgroup_memory=1 cgroup_enable=memory/' /boot/firmware/cmdline.txt
+   ```
+
+1. Reboot:
+
+   ```bash
+   sudo reboot
+   ```
+
+1. Confirm that the list of cgroup controllers now includes `memory`:
+
+   ```console
+   $ cat /sys/fs/cgroup/cgroup.controllers
+   cpuset cpu io memory pids
+
+   $ cat /sys/fs/cgroup/cgroup.subtree_control
+   cpuset cpu io memory pids
+   ```
+
+Read more about cgroup controllers in [The Linux Kernel](https://docs.kernel.org/admin-guide/cgroup-v2.html#controlling-controllers) documentation.
+
+</details>

docs/images/install/coder-setup.png

@@ -49,7 +49,7 @@ To start the Coder server:
 coder server
 ```
 
-![Coder install](../images/install/coder-setup.png)
+![Coder install](../images/screenshots/welcome-create-admin-user.png)
 
 To log in to an existing Coder deployment:
 

docs/images/screenshots/welcome-create-admin-user.png

@@ -60,7 +60,7 @@ To start the Coder server:
 coder server
 ```
 
-![Coder install](../images/install/coder-setup.png)
+![Coder install](../images/screenshots/welcome-create-admin-user.png)
 
 To log in to an existing Coder deployment: