Demo content from demo/user-guide (0c17989)

example-kernel-update/index.md

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+---
+id: example-kernel-update
+title: "Example: Kernel update"
+description: A complete process page — tables, a draw.io swimlane, an Excalidraw sketch and a video — created from the process template.
+tags: [example, process, template]
+lang: en
+---
+
+# Example: Kernel update
+
+This page is a worked example. It documents a fictitious process — updating
+the kernel on a fleet of Linux servers — and shows most of what a page in
+f451 can contain. It was started from the **Process runbook** template; see
+[[templates-and-metadata]] for how templates work.
+
+> [!NOTE]
+> What this page demonstrates: tables, callouts, a **draw.io** diagram
+> (swimlane), an **Excalidraw** sketch, an embedded **YouTube** video and
+> links to other pages. Open it in the editor to see how each is written —
+> both diagrams can be edited right there.
+
+## Profile
+
+| Field         | Value                                           |
+| ------------- | ----------------------------------------------- |
+| Process ID    | OPS-LNX-001                                     |
+| Process owner | Platform team                                   |
+| Scope         | All Linux servers (development, staging, production) |
+| Trigger       | Security advisory, vendor release, planned maintenance window |
+| Purpose       | Keep every server on a current, supported and secure kernel |
+
+## Process flow
+
+The lifecycle as a swimlane — one lane per role. This is a **draw.io**
+diagram: the image you see and its editable source live in the same file,
+`_media/lifecycle.drawio.svg`, next to this page.
+
+![Kernel update lifecycle](_media/lifecycle.drawio.svg)
+
+The technical core, sketched by hand. This one is an **Excalidraw** drawing
+(`_media/rollback.excalidraw.svg`) — quicker to draw, deliberately informal.
+
+![Happy path and rollback](_media/rollback.excalidraw.svg)
+
+## Steps
+
+1. **Request** — raise a change: servers, target kernel, maintenance window, risk.
+2. **Assessment and approval** — the platform team assesses; the change manager approves.
+   No approval without the mandatory documents below.
+3. **Preparation** — install the new kernel on development servers and run the smoke tests.
+4. **Staging** — roll out to staging, run the regression tests, record the result.
+5. **Production** — roll out in the approved window, one group of servers at a time.
+6. **Acceptance** — the service owner confirms the functional checks.
+7. **Closure** — close the change, update the inventory, attach the evidence.
+
+> [!WARNING]
+> Keep the previous kernel installed until acceptance. It is the rollback
+> path: if the checks fail after the reboot, boot the previous kernel and
+> reopen the change.
+
+## Technical execution
+
+```sh
+# Record the current state
+uname -r > /var/tmp/kernel-before.txt
+
+# Install the new kernel (Debian/Ubuntu shown; adapt to your distribution)
+sudo apt-get update && sudo apt-get install --only-upgrade linux-image-generic
+
+# Reboot inside the maintenance window, then verify
+sudo systemctl reboot
+uname -r
+systemctl --failed
+```
+
+## Responsibilities
+
+| Activity              | Requester | Platform team | Change manager | Service owner |
+| --------------------- | --------- | ------------- | -------------- | ------------- |
+| Raise change          | R/A       | C             | I              | C             |
+| Technical assessment  | I         | R             | A              | C             |
+| Approval              | I         | C             | A/R            | C             |
+| Perform update        | I         | R/A           | I              | I             |
+| Functional acceptance | I         | C             | I              | R/A           |
+
+*R = Responsible · A = Accountable · C = Consulted · I = Informed*
+
+## Required documents
+
+| Document                    | Mandatory | Where                  |
+| --------------------------- | --------- | ---------------------- |
+| Change request              | yes       | Ticket system          |
+| Test record (staging)       | yes       | Attached to the change |
+| Rollback plan               | yes       | This page, step 7      |
+| Acceptance record           | yes       | Attached to the change |
+
+## Background
+
+Why the kernel matters, from the person who started it:
+
+https://www.youtube.com/watch?v=o8NPllzkFhE
+
+Related: [[writing-a-page]] explains how a change to this page goes through
+review before it is published.