Add incremental RST-to-MyST swap mechanism (#1857)

* feat: add swap_sources.py for incremental RST-to-MyST migration

Pre-build swap/restore script that renames md-{name}.md → {name}.md
before Sphinx builds and restores after. Includes state tracking,
exclude file generation, collision detection, and partial-failure
rollback. 10 tests cover all specified behaviors plus rollback path.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* feat: add import_myst.py for importing MyST files from myst/* branches

Adds scripts/import_myst.py with import_page, git_show, list_myst_files,
list_rst_files, and do_import. Imported files are written as md-{name}.md
alongside existing RST files; importing is decoupled from swap activation.

Adds tests/test_import_myst.py covering single-page write, identical-skip,
warn-on-different-without-force, force-overwrite, and nested-path creation.
All 5 tests pass on Python 3.9.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* feat: add MyST swap exclude patterns and directive config to conf.py

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* feat: add swap-wrapped rendering targets to Makefile

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* feat: add swap pre/post build hooks for ReadTheDocs

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* feat: add empty _swap.txt, remove atexit from swap script

The atexit handler in --swap mode caused immediate restore on process
exit, breaking standalone usage. Makefile trap and RTD post_build
handle restore reliably.

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* feat: activate quick-start as MyST canary via swap mechanism

Imports docs/md-quick-start.md from origin/myst/current and adds
quick-start to docs/_swap.txt. Validates the swap pipeline end-to-end
on one page: import_myst pulls the MD via git show, swap_sources
renames md-quick-start.md to quick-start.md, sphinx-build renders
quick-start.html with zero MD-specific warnings, and restore reverses
the rename cleanly.

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* feat: activate 106 visual-validated canaries via swap

Imports 105 MD files (plus quick-start already present) from
origin/myst/current and adds them to docs/_swap.txt. The selection
is the BackstopJS visual-passers cohort: pages with <5% rendered
diff vs the live RST docs at docs.vyos.io/en/latest/, filtered to
those with an RST counterpart on current and no cmdincludemd usage
(template-format reconciliation pending).

Local sphinx-build with all 106 swapped: succeeded with 100
warnings (vs 95 baseline). The 5 new warnings are all undefined
cross-reference labels, not build failures:
- contributing/development.md (missing 'coding-guidelines')
- operation/upgrade-recovery.md (3 missing 'how_it_works' /
  'cancelling_recovery')
- vpp/configuration/dataplane/{buffers,memory,unix}.md (missing
  'vpp_config_dataplane_*' labels)

Source list: ~/.claude/projects/-Users-vybot-GitHub-vyos-documentation/docs/2026-04-29-myst-conversion-audit/visual-passers-under-5pct.txt
BackstopJS report: claude/gifted-hertz-74b9f9 worktree
(visual-compare/), 2026-04-23 vs vyos--1838.org.readthedocs.build.

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* fix: re-import 4 canary md-*.md files with xref label fixes

Re-imports the dash-form-corrected versions of:
- contributing/md-development.md (added (coding-guidelines)= anchor)
- operation/md-upgrade-recovery.md (3 ref renames: how_it_works /
  cancelling_recovery -> dash form)
- vpp/configuration/dataplane/md-buffers.md (vpp_config_dataplane_physmem
  -> vpp-config-dataplane-physmem)
- vpp/configuration/dataplane/md-unix.md
  (vpp_config_dataplane_interface_rx_mode
  -> vpp-config-dataplane-interface-rx-mode)

Source: origin/myst/current commit 59fbe3ea. Verified locally: clean
swap-build no longer reports any of the 5 target labels (1 of 6 —
vpp-config-hugepages — remains because system.md isn't in the canary
swap list; that anchor lives there).

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* fix: re-add 4 canary md-*.md files deleted by 242b334a

Commit 242b334a accidentally staged deletions instead of modifications
because the working tree had unprefixed *.md files left over from an
incomplete swap-restore cycle. Re-imports the same 4 files from
origin/myst/current with the xref label fixes applied:

- contributing/md-development.md       — (coding-guidelines)= anchor
- operation/md-upgrade-recovery.md     — how_it_works → how-it-works,
                                         cancelling_recovery → cancelling-recovery
- vpp/configuration/dataplane/md-buffers.md — vpp_config_dataplane_physmem
                                              → vpp-config-dataplane-physmem
- vpp/configuration/dataplane/md-unix.md   — vpp_config_dataplane_interface_rx_mode
                                              → vpp-config-dataplane-interface-rx-mode

Source: origin/myst/current commit 59fbe3ea.

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* fix: resolve remaining xref label gaps in swap-active build

Three small additions clear the cross-reference warnings tied to
underscore-vs-dash label form mismatches and the vpp-config-hugepages
reference that previously needed system.md in the canary set.

- system.rst: add .. _vpp-config-hugepages: alongside the existing
  underscore label so memory.md references resolve regardless of
  whether system.md is swap-active.
- md-lcp.md: add (vpp_config_dataplane_lcp_ignore-kernel-routes)=
  alongside dash form (carries upstream from myst/current 079fa786).
- md-memory.md: add (vpp_config_dataplane_memory)= alongside dash
  form (also from myst/current 079fa786).

Local clean swap-build with 106 canaries:
  before: 305 warnings, 8 undefined-label entries in our scope
  after:  300 warnings, 0 undefined-label entries in our scope

Remaining undefined-label warnings (release-notes, prepare_commit)
are in documentation.rst and unrelated to the canary swap mechanism.

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* fix: re-add md-lcp.md and md-memory.md (deleted by 870c9e7e)

Same disaster pattern as 242b334a: a swap-restore cycle left
unprefixed *.md files in the working tree, and the subsequent
git add staged deletions instead of modifications. Restoring the
two affected md-*.md files from origin/myst/current 079fa786
(which has the dual underscore+dash anchors needed for the
swap-active build).

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* feat: expand canaries to 114; refresh 3 with cfgcmd body fix

Adds 8 new visual-validated canaries from the post-cfgcmd-fix
BackstopJS run (2026-04-29):

- configuration/policy/as-path-list
- configuration/policy/community-list
- configuration/policy/extcommunity-list
- configuration/policy/large-community-list
- configuration/policy/local-route
- configuration/policy/prefix-list
- configuration/service/salt-minion
- configuration/system/updates

Refreshes 3 existing canaries whose MD content changed via the
cfgcmd/opcmd single-line body fix on myst/current fc19ab5c:

- configuration/firewall/global-options
- configuration/firewall/groups
- configuration/policy/route

All 11 sourced from origin/myst/current. Net: 106 -> 114 canaries.

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* fix: re-import md-cloud-init.md (block 3 fix from myst/current)

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* feat(swap): import .md files and webp transition from myst/current

Selective import from origin/myst/current (cf9c9b34):
- Add/update 255 .md files (full MyST conversion plus webp ref updates)
- Delete 175 PNG/JPG from docs/_static/images (webp twins already present)
- Delete 5 autotest topology.png (webp twins already present)

Preserved on swap (untouched):
- All .rst files (incremental swap pattern)
- conf.py, _ext/, _include/*.txt, .gitignore
- 115 canary md-*.md files
- 7 superpowers/specs/*.md design docs
- Logos vyos-logo.png / vyos-logo-icon.png (referenced by conf.py)

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* chore(swap): remove canary md-*.md files and docs/superpowers

- Remove 115 canary md-*.md files (incremental swap helpers no longer needed)
- Remove 8 files under docs/superpowers (project planning/design docs that
  shouldn't ship in the documentation tree)

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* docs: address Copilot review feedback on imported MyST pages

Fix issues flagged by Copilot review on PR #1857 (the same content lives
in myst/current as the canonical source):

Real bugs:
- site-2-site-cisco.md: replace curly quote (U+2019) with ASCII apostrophe
- rsa-keys.md: fix typo "key-pair nam>>" → "key-pair name>"
- vmware.md: lowercase admonition directive (:::{NOTE} → :::{note})
- vpp/configuration/nat/index.md: remove blank line inside {include} fence

Grammar:
- vpp/configuration/interfaces/loopback.md: "bounded" → "bound"
- vpp/configuration/sflow.md: "VyOS support" → "VyOS supports"
- vpp/requirements.md: "bypass" → "bypasses"
- vpp/configuration/dataplane/interface.md: "configures" → "configure"

CI linter (IP addresses):
- nmp.md: wrap 8.8.8.8 example with stop/start_vyoslinter
- lac-lns.md: wrap LNS config block (contains 8.8.8.8)
- wan-load-balancing.md: wrap whole file (illustrative non-RFC IPs)
- policy/examples.md: replace 192.0.1.1 with RFC 5737 192.0.2.1

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* fix(swap): address Copilot review feedback on swap infrastructure

Category D — drop obsolete canary mechanism settings:
- conf.py: remove '**/md-*.md' from exclude_patterns (no canaries left)
- Makefile: replace malformed '*/_build/*' with '$(BUILDDIR)/**' and drop
  the '*/md-*' ignore (canary files no longer exist)

Category C — script robustness:
- import_myst.py:
  * list_myst_files() now raises SystemExit on git ls-tree failure instead
    of silently returning [] (would have masked typo'd --source refs)
  * list_rst_files() skips _build/ when scanning for .rst stems
  * import_page() rejects stems containing '..' or absolute paths and
    re-checks that the resolved destination stays under docs_dir
  * --dry-run uses a separate "would_import" counter; summary line now
    distinguishes dry-run from actual imports
- swap_sources.py:
  * parse_swap_list() reads with explicit encoding='utf-8'
  * do_restore() validates state file version + entry shape before
    renaming files; raises with actionable message on corruption
  * State file reads/writes use explicit encoding='utf-8' throughout

_swap.txt:
- Wrap long comment line to satisfy 80-character doc-linter limit

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* refactor(swap): rename imported .md files to md- prefix for swap mechanism

Restore the canary file naming convention that swap_sources.py expects:
the imported MyST pages now live as docs/<dir>/md-<name>.md alongside
the existing docs/<dir>/<name>.rst, so swap_sources.py --swap can rename
them into place at build time.

- 254 .md files renamed (every page with a matching .rst counterpart)
- 2 MyST-only pages left at their final names (no .rst exists, no swap
  needed): docs/copyright.md, docs/automation/terraform/terraformvyos.md

All 114 stems listed in docs/_swap.txt now have a corresponding
md-<name>.md source file ready to swap in.

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* docs: address CodeRabbit review feedback on imported MyST pages

Fix issues flagged by CodeRabbit on PR #1857. All issues are pre-existing
in the upstream RST docs and inherited by the MyST conversion.

Real bugs:
- inter-vrf-routing-vrf-lite.md: invalid IPv6 next-hop "2001:db8::*" →
  "2001:db8::1"
- ipsec-pa-route-based.md: vendor mislabel "Cisco" → "Palo Alto"
  (header on line 39 and "Monitoring on Cisco side" section heading)
- bgp-ipv6-unnumbered.md: AS number mismatch between configuration and
  verification output for both routers (Router A: 65020 → 64496;
  Router B: 65021 → 64499)
- qos.md: class 30 used "match ADDRESS20" instead of ADDRESS30 — broke
  the documented pattern (classes 10/20/30 → ADDRESS10/20/30)

Security:
- OpenVPN_with_LDAP.md: redact full PEM private key material from the
  three "set pki ... private key '...'" lines and from the embedded
  OpenVPN client <key> block; replace with <REDACTED> / ...REDACTED...
  placeholders. Public certificates retained.

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* feat(swap): default to serving MyST for all swapped pages

Replace the previously-curated 114-stem _swap.txt with the full set of
254 imported md-prefixed pages, so MD is served by default at build
time. To revert any specific page back to RST, remove its stem from
_swap.txt (or comment it out).

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* fix(ext): handle RST fallback in CmdInclude when _renderer absent

`cmdincludemd` is in `myst_fence_as_directive`, so MyST routes
fence blocks through `render_fence → render_restructuredtext →
MockRSTParser`. In that path `self.state` is a plain docutils Body
with no `_renderer`, crashing the build.

Fall back to `nested_parse` when `_renderer` is unavailable so the
directive works in both MyST and RST/MockRSTParser contexts.

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* feat(conf): copy .md sources into HTML output for plain-text serving

Adds a build-finished hook that mirrors every .md file from the Sphinx
source tree into the HTML output directory verbatim, making unrendered
MyST sources accessible alongside HTML renders at the same URL path.

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* docs: address review feedback from PR #1857

Fix conversion artifacts, typos, grammar errors, and technical
inaccuracies flagged by automated code review (Copilot + CodeRabbit).

Infrastructure: add root-level md-*.md exclusion to conf.py,
fix sphinx-autobuild ignore globs in Makefile.

Content: fix curly quotes, invalid Go panic() calls, shell quoting
in cURL examples, incorrect firewall command paths, typos across
22 documentation files, remove duplicate sections.

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---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

3 files changed, 831 insertions, 0 deletions

diff --git a/docs/configuration/loadbalancing/md-haproxy.md b/docs/configuration/loadbalancing/md-haproxy.md
new file mode 100644
index 00000000..d60c5248
--- /dev/null
+++ b/docs/configuration/loadbalancing/md-haproxy.md
@@ -0,0 +1,510 @@
+---
+lastproofread: '2026-04-06'
+---
+
+# HAproxy
+
+```{include} /_include/need_improvement.txt
+```
+
+HAProxy is a load balancer and proxy server that provides
+high-availability, load balancing, and proxying for TCP (level 4) and
+HTTP-based (level 7) applications.
+
+## Configuration
+
+Service configuration specifies the port to bind to. Backend
+configuration defines the load balancing method and specifies the backend
+servers.
+
+### Service
+
+```{cfgcmd} set load-balancing haproxy service \<name\> listen-address \<address\>
+
+Set the IP address for the service to bind to. By default, the service
+listens on all IPv4 and IPv6 addresses.
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> port \<port\>
+
+Create service *<name>* to listen on \<port\>
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> mode \<tcp|http\>
+
+Configure service *<name>* mode TCP or HTTP
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> backend \<name\>
+
+Configure service *<name>* to use the backend \<name\>
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> ssl certificate \<name\>
+
+Set the SSL certificate \<name\> for service \<name\>. You can define
+multiple certificates.
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> http-response-headers \<header-name\> value \<header-value\>
+
+Set custom HTTP headers to include in all responses.
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> logging facility \<facility\> level \<level\>
+
+Specify facility and level for logging.
+For an explanation on {ref}`syslog_facilities` and
+{ref}`syslog_severity_level`,
+see tables in the syslog configuration section.
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> timeout client \<seconds\>
+
+Set the maximum inactivity time on the client side for this service.
+Value range 1-3600 seconds.
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> http-compression algorithm \<gzip | deflate | identity | raw-deflate\>
+
+Set the compression algorithm to be used when compressing HTTP responses.
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> http-compression mime-type \<mime-type\>
+
+Set the list of HTTP response MIME types which haproxy will attempt to
+compress, if received uncompressed from backend server.
+```
+
+#### Rules
+
+Rules control and route incoming traffic to specific backends based on
+predefined conditions. Rules define matching criteria and specify actions
+to perform.
+
+```{cfgcmd} set load-balancing haproxy service \<name\> rule \<rule\> domain-name \<name\>
+
+Match domain name
+```
+
+````{cfgcmd} set load-balancing haproxy service \<name\> rule \<rule\> ssl \<sni\>
+
+```{eval-rst}
+SSL match Server Name Indication (SNI) option:
+ * ``req-ssl-sni`` SSL Server Name Indication (SNI) request match
+ * ``ssl-fc-sni`` SSL frontend connection Server Name Indication match
+ * ``ssl-fc-sni-end`` SSL frontend match end of connection Server Name
+
+    Indication
+```
+````
+
+````{cfgcmd} set load-balancing haproxy service \<name\> rule \<rule\> url-path \<match\> \<url\>
+
+Define URL path matching rules for a specific service. Use this command
+to specify how to match the URL path against incoming requests.
+
+```{eval-rst}
+The available options for <match> are:
+ * ``begin`` Matches the beginning of the URL path
+ * ``end`` Matches the end of the URL path.
+ * ``exact`` Matches the URL path exactly.
+```
+````
+
+```{cfgcmd} set load-balancing haproxy service \<name\> rule \<rule\> set backend \<name\>
+
+Assign a specific backend to a rule
+```
+
+```{cfgcmd} set load-balancing haproxy service \<name\> rule \<rule\> redirect-location \<url\>
+
+Redirect URL to a new location.
+```
+
+### Backend
+
+````{cfgcmd} set load-balancing haproxy backend \<name\> balance \<balance\>
+
+Specify the load balancing algorithm for distributing requests among
+available servers.
+
+```{eval-rst}
+Balance algorithms:
+ * ``source-address`` Distributes requests based on the source IP address
+   of the client.
+ * ``round-robin`` Distributes requests in a circular manner,
+   sequentially sending each request to the next server in line.
+ * ``least-connection`` Distributes requests to the server with the fewest
+   active connections.
+```
+````
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> mode \<mode\>
+
+Configure backend *<name>* mode TCP or HTTP.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> server \<name\> address \<x.x.x.x\>
+
+Set the address of the backend server that receives incoming traffic.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> server \<name\> port \<port\>
+
+Set the address of the backend port.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> server \<name\> check
+
+Active health check backend server.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> server \<name\> check port \<port\>
+
+Set an alternative port number for health checks.
+Overrides the default server port used for TCP/HTTP checks.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> server \<name\> send-proxy
+
+Send a Proxy Protocol version 1 header (text format).
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> server \<name\> send-proxy-v2
+
+Send a Proxy Protocol version 2 header (binary format).
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> ssl ca-certificate \<ca-certificate\>
+
+Use SSL encryption for backend requests and authenticate the backend
+against ``<ca-certificate>``.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> ssl no-verify
+
+Use SSL encryption for backend requests without validating the server
+certificate.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> http-response-headers \<header-name\> value \<header-value\>
+
+Set custom HTTP headers to include in all responses from the backend.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> logging facility \<facility\> level \<level\>
+
+Specify facility and level for logging.
+For an explanation on {ref}`syslog_facilities` and
+{ref}`syslog_severity_level`,
+see tables in the syslog configuration section.
+```
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> timeout check \<seconds\>
+
+Set the timeout in seconds for established connections.
+Value range 1-3600 seconds.
+```
+```{cfgcmd} set load-balancing haproxy backend \<name\> timeout connect \<seconds\>
+
+Set the maximum time to wait for a connection attempt to a server to succeed.
+Value range 1-3600 seconds.
+```
+
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> timeout server \<seconds\>
+
+Set the maximum inactivity time on the server side.
+Value range 1-3600 seconds.
+```
+
+### Global
+
+Global configuration parameters:
+
+```{cfgcmd} set load-balancing haproxy global-parameters max-connections \<num\>
+
+Limit maximum number of connections
+```
+
+
+```{cfgcmd} set load-balancing haproxy global-parameters ssl-bind-ciphers \<ciphers\>
+
+Limit the cipher algorithms allowed during SSL/TLS handshake.
+```
+
+
+```{cfgcmd} set load-balancing haproxy global-parameters tls-version-min \<version\>
+
+Specify the minimum required TLS version 1.2 or 1.3
+```
+
+
+```{cfgcmd} set load-balancing haproxy global-parameters logging facility \<facility\> level \<level\>
+
+Specify facility and level for logging.
+For an explanation on {ref}`syslog_facilities` and
+{ref}`syslog_severity_level`,
+see tables in the syslog configuration section.
+```
+
+
+```{cfgcmd} set load-balancing haproxy timeout check \<seconds\>
+
+Set the timeout in seconds for established connections.
+Value range 1-3600 seconds. Default is 5 seconds.
+```
+
+
+```{cfgcmd} set load-balancing haproxy timeout client \<seconds\>
+
+Set the maximum inactivity time on the client side.
+Value range 1-3600 seconds. Default is 50 seconds.
+```
+
+
+```{cfgcmd} set load-balancing haproxy timeout connect \<seconds\>
+
+Set the maximum time to wait for a connection attempt to a server to succeed.
+Value range 1-3600 seconds. Default is 10 seconds.
+```
+
+
+```{cfgcmd} set load-balancing haproxy timeout server \<seconds\>
+
+Set the maximum inactivity time on the server side.
+Value range 1-3600 seconds. Default is 50 seconds.
+```
+
+## Health checks
+
+
+### HTTP checks
+
+
+Use HTTP health checks to monitor web applications that provide health status
+information and determine their availability.
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> http-check
+
+Enables HTTP health checks using OPTION HTTP requests against '/' and
+expecting a successful response code in the 200-399 range.
+```
+
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> http-check method \<method\>
+
+Set the HTTP method: ``OPTION``, ``GET``, ``POST``, or ``PUT``.
+```
+
+
+```{cfgcmd} set load-balancing haproxy backend \<name\> http-check uri \<path\>
+
+Set the endpoint to use for health checks.
+```
+
+
+````{cfgcmd} set load-balancing haproxy backend \<name\> http-check expect \<condition\>
+
+Set the expected result condition for a server to be considered healthy.
+
+```{eval-rst}
+Some possible examples are:
+ * ``status 200`` Expecting a 200 response code
+ * ``status 200-399`` Expecting a non-failure response code
+ * ``string success`` Expecting the string success in the response body
+```
+````
+
+### TCP checks
+
+Configure health checks for TCP mode backends. You can configure protocol-aware
+checks for a range of Layer 7 protocols:
+
+````{cfgcmd} set load-balancing haproxy backend \<name\> health-check \<protocol\>
+
+```{eval-rst}
+Available health check protocols:
+ * ``ldap`` LDAP protocol check.
+ * ``redis`` Redis protocol check.
+ * ``mysql`` MySQL protocol check.
+ * ``pgsql`` PostgreSQL protocol check.
+ * ``smtp`` SMTP protocol check.
+```
+````
+
+:::{note}
+If you specify a server to check but do not configure a
+protocol, HAProxy performs a basic TCP health check. A server is online if
+it responds to a connection attempt with a valid `SYN/ACK` packet.
+:::
+## Redirect HTTP to HTTPS
+
+Configure a HAProxy service for HTTP that listens on port 80 and redirects
+incoming requests to HTTPS:
+
+```none
+set load-balancing haproxy service http port '80'
+set load-balancing haproxy service http redirect-http-to-https
+```
+
+You can use a different service name; in this example, `http` is just for
+convenience.
+
+## Examples
+### Level 4 balancing
+
+This configuration enables the TCP reverse proxy for the `my-tcp-api`
+service. Incoming TCP connections on port 8888 are load balanced across the
+backend servers (srv01 and srv02) using the round-robin load balancing
+algorithm.
+
+```none
+set load-balancing haproxy service my-tcp-api backend 'bk-01'
+set load-balancing haproxy service my-tcp-api mode 'tcp'
+set load-balancing haproxy service my-tcp-api port '8888'
+
+set load-balancing haproxy backend bk-01 balance 'round-robin'
+set load-balancing haproxy backend bk-01 mode 'tcp'
+
+set load-balancing haproxy backend bk-01 server srv01 address '192.0.2.11'
+set load-balancing haproxy backend bk-01 server srv01 port '8881'
+set load-balancing haproxy backend bk-01 server srv02 address '192.0.2.12'
+set load-balancing haproxy backend bk-01 server srv02 port '8882'
+```
+
+### Balancing based on domain name
+
+The following configuration demonstrates how to use VyOS
+to achieve load balancing based on the domain name:
+
+The HTTP service listens on TCP port 80.
+
+Rule 10 matches requests with the domain name `node1.example.com` and
+forwards them to the backend `bk-api-01`.
+
+Rule 20 matches requests with the domain name `node2.example.com` and
+forwards them to the backend `bk-api-02`.
+
+```none
+set load-balancing haproxy service http description 'bind app listen on 443 port'
+set load-balancing haproxy service http mode 'tcp'
+set load-balancing haproxy service http port '80'
+
+set load-balancing haproxy service http rule 10 domain-name 'node1.example.com'
+set load-balancing haproxy service http rule 10 set backend 'bk-api-01'
+set load-balancing haproxy service http rule 20 domain-name 'node2.example.com'
+set load-balancing haproxy service http rule 20 set backend 'bk-api-02'
+
+set load-balancing haproxy backend bk-api-01 description 'My API-1'
+set load-balancing haproxy backend bk-api-01 mode 'tcp'
+set load-balancing haproxy backend bk-api-01 server api01 address '127.0.0.1'
+set load-balancing haproxy backend bk-api-01 server api01 port '4431'
+set load-balancing haproxy backend bk-api-02 description 'My API-2'
+set load-balancing haproxy backend bk-api-02 mode 'tcp'
+set load-balancing haproxy backend bk-api-02 server api01 address '127.0.0.2'
+set load-balancing haproxy backend bk-api-02 server api01 port '4432'
+```
+
+### Terminate SSL
+
+The following configuration terminates SSL on the router.
+
+The `http` service listens on port 80 and redirects HTTP requests to
+HTTPS.
+
+The `https` service listens on port 443 with the `bk-default` backend
+and handles HTTPS traffic using the `cert` certificate for SSL termination.
+The HSTS header is set with a 1-year expiry to tell browsers to always use
+SSL for the site.
+
+Rule 10 matches requests with the exact URL path `/.well-known/xxx` and
+redirects them to `/certs/`.
+
+Rule 20 matches requests with URL paths ending in `/mail` or the exact
+path `/email/bar` and redirects them to `/postfix/`.
+
+Global parameters include a maximum connection limit of 4000 and a minimum
+TLS version of 1.3.
+
+```none
+set load-balancing haproxy service http description 'Force redirect to HTTPS'
+set load-balancing haproxy service http port '80'
+set load-balancing haproxy service http redirect-http-to-https
+
+set load-balancing haproxy service https backend 'bk-default'
+set load-balancing haproxy service https description 'listen on 443 port'
+set load-balancing haproxy service https mode 'http'
+set load-balancing haproxy service https port '443'
+set load-balancing haproxy service https ssl certificate 'cert'
+set load-balancing haproxy service https http-response-headers Strict-Transport-Security value 'max-age=31536000'
+
+set load-balancing haproxy service https rule 10 url-path exact '/.well-known/xxx'
+set load-balancing haproxy service https rule 10 set redirect-location '/certs/'
+set load-balancing haproxy service https rule 20 url-path end '/mail'
+set load-balancing haproxy service https rule 20 url-path exact '/email/bar'
+set load-balancing haproxy service https rule 20 set redirect-location '/postfix/'
+
+set load-balancing haproxy backend bk-default description 'Default backend'
+set load-balancing haproxy backend bk-default mode 'http'
+set load-balancing haproxy backend bk-default server sr01 address '192.0.2.23'
+set load-balancing haproxy backend bk-default server sr01 port '80'
+
+set load-balancing haproxy global-parameters max-connections '4000'
+set load-balancing haproxy global-parameters tls-version-min '1.3'
+```
+
+### SSL Bridging
+
+The following configuration terminates incoming HTTPS traffic on the router,
+then re-encrypts the traffic and sends it to the backend server via HTTPS.
+Use this when encryption is required for both paths but you do not want to
+install publicly trusted certificates on each backend server.
+
+Backend service certificates are checked against the certificate authority
+specified in the configuration, which could be an internal CA.
+
+The `https` service listens on port 443 with backend `bk-bridge-ssl` to
+handle HTTPS traffic. It uses certificate named `cert` for SSL termination.
+
+The `bk-bridge-ssl` backend connects to `sr01` server on port 443 via HTTPS
+and checks backend server has a valid certificate trusted by CA `cacert`
+
+```none
+set load-balancing haproxy service https backend 'bk-bridge-ssl'
+set load-balancing haproxy service https description 'listen on 443 port'
+set load-balancing haproxy service https mode 'http'
+set load-balancing haproxy service https port '443'
+set load-balancing haproxy service https ssl certificate 'cert'
+
+set load-balancing haproxy backend bk-bridge-ssl description 'SSL backend'
+set load-balancing haproxy backend bk-bridge-ssl mode 'http'
+set load-balancing haproxy backend bk-bridge-ssl ssl ca-certificate 'cacert'
+set load-balancing haproxy backend bk-bridge-ssl server sr01 address '192.0.2.23'
+set load-balancing haproxy backend bk-bridge-ssl server sr01 port '443'
+```
+
+### Balancing with HTTP health checks
+
+This configuration enables HTTP health checks for backend servers.
+
+```none
+set load-balancing haproxy service my-tcp-api backend 'bk-01'
+set load-balancing haproxy service my-tcp-api mode 'tcp'
+set load-balancing haproxy service my-tcp-api port '8888'
+
+set load-balancing haproxy backend bk-01 balance 'round-robin'
+set load-balancing haproxy backend bk-01 mode 'tcp'
+
+set load-balancing haproxy backend bk-01 http-check method 'get'
+set load-balancing haproxy backend bk-01 http-check uri '/health'
+set load-balancing haproxy backend bk-01 http-check expect 'status 200'
+
+set load-balancing haproxy backend bk-01 server srv01 address '192.0.2.11'
+set load-balancing haproxy backend bk-01 server srv01 port '8881'
+set load-balancing haproxy backend bk-01 server srv01 check
+set load-balancing haproxy backend bk-01 server srv02 address '192.0.2.12'
+set load-balancing haproxy backend bk-01 server srv02 port '8882'
+set load-balancing haproxy backend bk-01 server srv02 check port '8892'
+```
diff --git a/docs/configuration/loadbalancing/md-index.md b/docs/configuration/loadbalancing/md-index.md
new file mode 100644
index 00000000..3241edb7
--- /dev/null
+++ b/docs/configuration/loadbalancing/md-index.md
@@ -0,0 +1,15 @@
+---
+lastproofread: '2026-04-06'
+---
+
+(load-balancing)=
+
+# Load-balancing
+
+```{toctree}
+:includehidden: true
+:maxdepth: 1
+
+wan
+haproxy
+```
diff --git a/docs/configuration/loadbalancing/md-wan.md b/docs/configuration/loadbalancing/md-wan.md
new file mode 100644
index 00000000..a19bbfae
--- /dev/null
+++ b/docs/configuration/loadbalancing/md-wan.md
@@ -0,0 +1,306 @@
+---
+lastproofread: '2026-04-06'
+---
+
+# WAN load balancing
+
+```{todo}
+Convert raw command blocks in this file to cfgcmd/opcmd
+directives for command coverage tracking.
+```
+
+The load balancer distributes outbound traffic across two or more
+interfaces. If a path fails, the load balancer balances traffic across the
+remaining healthy paths. When a path recovers, it is automatically added back
+to the routing table. The load balancer adds routes for each path and
+distributes traffic based on interface health and weight.
+
+In a minimal configuration, the following must be provided:
+> - An interface with a `nexthop`.
+> - One rule with a LAN (inbound-interface) and the WAN (interface).
+
+The following examples uses two DHCP WAN interfaces and one LAN (`eth2`):
+
+```none
+set load-balancing wan interface-health eth0 nexthop 'dhcp'
+set load-balancing wan interface-health eth1 nexthop 'dhcp'
+set load-balancing wan rule 1 inbound-interface 'eth2'
+set load-balancing wan rule 1 interface eth0
+set load-balancing wan rule 1 interface eth1
+```
+
+:::{note}
+Do not use WAN load balancing with dynamic routing protocols. This
+feature creates customized routing tables and firewall rules that are
+incompatible with routing protocols.
+:::
+
+## Load balancing rules
+
+You define interfaces, their weight, and the traffic type to balance in
+numbered rule sets. The load balancer executes rules in numerical order
+against outgoing packets. When a packet matches a rule, it is sent through the
+specified interface. Packets that do not match any rule use the system routing
+table. You cannot change rule numbers.
+
+Create a load balancing rule, it can be a number between 1 and 9999:
+
+```none
+vyos@vyos# set load-balancing wan rule 1
+Possible completions:
+description             Description for this rule
+> destination           Destination
+exclude                 Exclude packets matching this rule from wan load balance
+failover                Enable failover for packets matching this rule from wan load balance
+inbound-interface       Inbound interface name (e.g., "eth0") [REQUIRED]
++> interface            Interface name [REQUIRED]
+> limit                 Enable packet limit for this rule
+per-packet-balancing    Option to match traffic per-packet instead of the default, per-flow
+protocol                Protocol to match
+> source                Source information
+```
+
+
+### Interface weight
+
+By default, the load balancer distributes outbound
+traffic randomly across available interfaces. You can assign weights to
+interfaces to influence the distribution. If `eth0` has more bandwidth
+than `eth1`, you can assign a higher weight to `eth0` to send more
+traffic through it:
+
+```none
+set load-balancing wan rule 1 interface eth0 weight 2
+set load-balancing wan rule 1 interface eth1 weight 1
+```
+
+In this example,\`\`eth0\`\` receives 66% of traffic, and `eth1` receives
+33% of traffic.
+
+### Rate limit
+
+Set a packet rate limit for a rule to apply it to traffic above or below a
+specified threshold. To configure rate limiting, use:
+
+```none
+set load-balancing wan rule <rule> limit <parameter>
+```
+
+- `burst`: Number of packets allowed to overshoot the limit within `period`.
+  Default 5.
+- `period`: Time window for rate calculation. Possible values:
+  `second` (one second), `minute` (one minute), `hour` (one hour).
+  Default is `second`.
+- `rate`: Number of packets. Default: `5`.
+- `threshold`: `below` or `above` the specified rate limit.
+
+### Flow and packet-based balancing
+
+The load balancer balances outgoing traffic by flow. A connection tracking
+table tracks flows by source address, destination address, and port. Each
+flow is assigned to an interface based on the balancing rules, and subsequent
+packets use the same interface. This ensures packets arrive in order when links
+have different speeds.
+
+Packet-based balancing can improve balance across interfaces when packet
+order is not critical. Enable per-packet balancing for a rule with:
+
+```none
+set load-balancing wan rule <rule> per-packet-balancing
+```
+
+
+### Exclude traffic
+
+To exclude traffic from load balancing, traffic matching an exclude rule
+bypasses load balancing and uses the system routing table instead:
+
+```none
+set load-balancing wan rule <rule> exclude
+```
+
+
+## Health checks
+
+The load balancer periodically checks the health of interfaces and paths by
+sending ICMP packets (ping) to remote destinations, performing TTL tests, or
+executing a user-defined script. If an interface fails the health check, the
+load balancer removes it from its interface pool.
+To enable health checking for an interface:
+
+```none
+vyos@vyos# set load-balancing wan interface-health <interface>
+Possible completions:
+failure-count    Failure count
+nexthop          Outbound interface nexthop address. Can be 'dhcp or ip address' [REQUIRED]
+success-count    Success count
++> test          Rule number
+```
+
+Specify the nexthop on the path to the destination. You can set
+`ipv4-address` to `dhcp`.
+
+```none
+set load-balancing wan interface-health <interface> nexthop <ipv4-address>
+```
+
+Set the number of health check failures before the load balancer marks an
+interface as unavailable (range 1-10, default 1). Or set the number of
+successful health checks before adding an interface back to the pool
+(range 1-10, default 1).
+
+```none
+set load-balancing wan interface-health <interface> failure-count <number>
+set load-balancing wan interface-health <interface> success-count <number>
+```
+
+Configure each health check in its own test. Tests are numbered and processed
+in numeric order. You can define multiple tests for multi-target health
+checking:
+
+```none
+vyos@vyos# set load-balancing wan interface-health eth1 test 0
+Possible completions:
+resp-time    Ping response time (seconds)
+target       Health target address
+test-script  Path to user defined script
+ttl-limit    Ttl limit (hop count)
+type         WLB test type
+```
+
+- `resp-time`: The maximum response time for ping in seconds. Range
+  1-30, default `5`.
+- `target`: The target to receive ICMP packets. The address can be an IPv4
+  address or hostname.
+- `test-script`: A user-defined script must return 0 to succeed and
+  non-zero to fail. Scripts reside in `/config/scripts`. For other locations,
+  provide the full path.
+- `ttl-limit`: For the UDP TTL limit test, specify the hop count limit.
+  The limit must be shorter than the path length. The test succeeds when an
+  ICMP time-expired message is returned. Default `1`.
+- `type`: Specify the test type: `ping`, `ttl`, or a user-defined
+  script.
+
+## Source NAT rules
+
+By default, interfaces in a load balancing pool replace the source IP of
+each outgoing packet with their own address to ensure replies arrive on the
+same interface. The load balancer handles this through automatically generated
+Source NAT (SNAT) rules applied only to balanced traffic. To disable the
+automatic generation of SNAT rules when this behavior is not desired, use:
+
+```none
+set load-balancing wan disable-source-nat
+```
+
+
+## Sticky connections
+
+Inbound connections to a WAN interface can be improperly handled when
+replies are sent back to the client.
+
+```{image} /_static/images/sticky-connections.webp
+:align: center
+:width: 80%
+```
+
+When responding to an incoming packet, you may want to ensure the response
+leaves from the same interface as the incoming packet. Enable sticky
+connections in the load balancer to do this:
+
+```none
+set load-balancing wan sticky-connections inbound
+```
+
+
+## Failover
+
+In failover mode, one interface is primary and other interfaces are
+secondary or spare. The load balancer uses only the primary interface. If it
+fails, a secondary interface from the available pool takes over. The load
+balancer selects the primary interface based on its weight and health. Other
+interfaces become secondary. Secondary interfaces are chosen based on their
+weight and health. You can also select interface roles based on rule order by
+including interfaces in balancing rules and ordering those rules accordingly.
+To enable failover mode, create a failover rule:
+
+```none
+set load-balancing wan rule <number> failover
+```
+
+Existing sessions do not automatically fail over to a new path. Flush the
+session table on each connection state change to enable failover:
+
+```none
+set load-balancing wan flush-connections
+```
+
+:::{warning}
+Flushing the session table causes other connections to revert from
+flow-based to packet-based balancing until each flow is reestablished.
+:::
+
+## Script execution
+
+Run a script when an interface state changes. Scripts run from the
+`/config/scripts` directory. To use a script in another location,
+specify the full path:
+
+```none
+set load-balancing wan hook script-name
+```
+
+Two environment variables are available:
+- `WLB_INTERFACE_NAME=[interfacename]`: Interface to be monitored
+- `WLB_INTERFACE_STATE=[ACTIVE|FAILED]`: Interface state
+
+:::{warning}
+Blocking call with no timeout: VyOS becomes unresponsive if the
+script does not return.
+:::
+
+## Handling and monitoring
+
+The following command shows WAN load balancer information including test
+types and targets. The character at the start of each line indicates the test
+state:
+- `+` successful.
+- `-` failed.
+- A blank indicates that no test has been carried out.
+
+```none
+vyos@vyos:~$ show wan-load-balance
+Interface:  eth0
+Status:  failed
+Last Status Change:  Tue Jun 11 20:12:19 2019
+-Test:  ping  Target:
+    Last Interface Success:  55s
+    Last Interface Failure:  0s
+    # Interface Failure(s):  5
+
+Interface:  eth1
+Status:  active
+Last Status Change:  Tue Jun 11 20:06:42 2019
++Test:  ping  Target:
+    Last Interface Success:  0s
+    Last Interface Failure:  6m26s
+    # Interface Failure(s):  0
+```
+
+Show connection data of load balanced traffic:
+
+```none
+vyos@vyos:~$ show wan-load-balance connection
+conntrack v1.4.2 (conntrack-tools): 3 flow entries have been shown.
+Type    State           Src                     Dst                     Packets Bytes
+tcp     TIME_WAIT       10.1.1.13:38040         203.0.113.2:80          203.0.113.2  192.168.188.71
+udp                     10.1.1.13:41891         198.51.100.3:53         198.51.100.3 192.168.188.71
+udp                     10.1.1.13:55437         198.51.100.3:53         198.51.100.3 192.168.188.71
+```
+
+
+### Restart
+
+```none
+restart wan-load-balance
+```