feat: flip swap mechanism — MD as primary, RST as override (Phase 1)

This is the first of three phases inverting the per-page swap mechanism
so MD becomes the canonical primary and RST becomes the rare override.

Phase 1 — file renames + conf.py exclude_patterns flip only:
- Rename docs/**/md-<stem>.md to docs/**/<stem>.md (drop md- prefix)
  for all 254 stems previously listed in docs/_swap.txt
- Rename docs/**/<stem>.rst to docs/**/rst-<stem>.rst (add rst- prefix)
  for the same 254 stems
- Repurpose docs/_swap.txt as docs/_rst_overrides.txt; initially empty
  comment-only since no pages need the RST fallback right now
- conf.py exclude_patterns flipped: rst-*.rst is now excluded by default
  instead of md-*.md
- conf.py runtime-artifact references updated to _rst_override_state.json
  and _md_exclude.txt (Phase 2 will rewrite swap_sources.py to produce
  these names; for now no swap script runs because overrides list is empty)

Phase 2 (next commit on this branch) will rewrite scripts/swap_sources.py
with inverted rename direction, delete scripts/import_myst.py + tests, and
update tests/test_swap_sources.py for the new semantics.

Phase 3 will be the cleanup pass and ready-for-review flip.

Generated by robots https://vyos.io

1 files changed, 59 insertions, 0 deletions

diff --git a/docs/vpp/configuration/dataplane/logging.md b/docs/vpp/configuration/dataplane/logging.md
new file mode 100644
index 00000000..50e6277b
--- /dev/null
+++ b/docs/vpp/configuration/dataplane/logging.md
@@ -0,0 +1,59 @@
+---
+lastproofread: '2026-02-27'
+---
+
+(vpp-config-dataplane-logging)=
+
+```{include} /_include/need_improvement.txt
+```
+
+
+# VPP Logging Configuration
+
+VPP logging is an important part of monitoring and troubleshooting
+the performance and behavior of the VPP dataplane.
+
+VPP stores logs in two places:
+- `/var/log/vpp.log` — This file contains logs related to daemon
+  startup and logs of commands executed directly via VPP CLI. Pay
+  attention: VyOS does not use VPP CLI for configuration, so this log
+  will not contain any configuration changes made via VyOS CLI and will
+  not be informative in most cases.
+- System journal — contains logs related to the VPP daemon work,
+  including errors, warnings, and informational messages. It is the
+  main destination of logs generated by VPP.
+
+Logging detail level can be configured via the next command:
+
+```{cfgcmd} set vpp settings logging default-level \<level\>
+```
+
+Where `<level>` can be one of the following:
+
+- `emerg` (Emergency) - System is unusable.
+- `alert` (Alert) - Immediate action required.
+- `crit` (Critical) - Critical conditions.
+- `error` (Error) - Error conditions.
+- `warn` (Warning) - Warning conditions.
+- `notice` (Notice) - Normal but significant.
+- `info` (Informational) - Routine informational messages.
+- `debug` (Debug) - Detailed debugging messages.
+- `disabled` (Disabled) - Logging disabled.
+
+It is recommended to set logging level to `debug` only for
+troubleshooting purposes, as it can generate a large volume of log
+data. For regular operation, a level of `info` or `warn` is usually
+sufficient.
+
+## Troubleshooting
+
+Improper logging configuration can lead to various issues, including:
+
+- Excessive log file sizes if the logging level is set too high
+  (for example, `debug`).
+- Missing critical information if the logging level is set too low
+  (for example, `alert`).
+- Performance degradation due to excessive logging overhead
+
+Consider adjusting the logging level if you experience issues mentioned
+above.