feat: flip swap mechanism on sagitta — MD as primary, RST as override

Mirror of #1899 (current) and #1900 (circinus) for sagitta. Same logic,
same scripts, per-branch file set.

Changes:
- Rename docs/**/md-<stem>.md to docs/**/<stem>.md (drop md- prefix) for
  all 210 stems previously listed in docs/_swap.txt
- Rename docs/**/<stem>.rst to docs/**/rst-<stem>.rst (add rst- prefix)
  for the same 210 stems
- Repurpose docs/_swap.txt as docs/_rst_overrides.txt; initially empty
- conf.py exclude_patterns flipped: rst-*.rst excluded by default
- conf.py runtime-artifact references updated to _rst_override_state.json
  and _md_exclude.txt
- scripts/swap_sources.py imported from current (post-#1899 rewrite, with
  inverted rename direction)
- scripts/import_myst.py and tests/test_import_myst.py deleted (obsolete)
- tests/test_swap_sources.py imported from current (post-#1899 rewrite)

Side-effect: fixes the same 404 on /en/1.4/ View page source links that
#1899 fixed for /en/rolling/ and #1900 fixed for /en/1.5/.

Per-branch differences vs #1899:
- sagitta has 210 stems vs current's 254 (sagitta has no vpp pages and
  fewer current-only features; cli + installation/cloud/aws are still
  RST-only on sagitta pending the title-level fix follow-up)
- otherwise the script/conf.py/test changes are byte-identical with current

Generated by robots https://vyos.io

1 files changed, 485 insertions, 0 deletions

diff --git a/docs/configuration/loadbalancing/reverse-proxy.md b/docs/configuration/loadbalancing/reverse-proxy.md
new file mode 100644
index 00000000..d9719425
--- /dev/null
+++ b/docs/configuration/loadbalancing/reverse-proxy.md
@@ -0,0 +1,485 @@
+# Reverse-proxy
+
+```{include} /_include/need_improvement.txt
+```
+
+VyOS reverse-proxy is 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 is responsible for binding to a specific port,
+while the backend configuration determines the type of load balancing
+to be applied and specifies the real servers to be utilized.
+
+### Service
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> listen-address
+   <address>
+
+  Set service to bind on IP address, by default listen on any IPv4 and IPv6
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> port
+   <port>
+
+  Create service `<name>` to listen on <port>
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> mode
+   <tcp|http>
+
+  Configure service `<name>` mode TCP or HTTP
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> backend
+   <name>
+
+  Configure service `<name>` to use the backend <name>
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> ssl
+   certificate <name>
+
+  Set SSL certificate <name> for service <name>
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name>
+  http-response-headers <header-name> value <header-value>
+
+  Set custom HTTP headers to be included in all responses
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy 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 syslog configuration section.
+
+```
+
+#### Rules
+
+Rules allow to control and route incoming traffic to specific backend based
+on predefined conditions. Rules allow to define matching criteria and
+perform action accordingly.
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> rule <rule>
+   domain-name <name>
+
+  Match domain name
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> rule <rule>
+   ssl <sni>
+
+  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
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> rule <rule>
+   url-path <match> <url>
+
+  Allows to define URL path matching rules for a specific service.
+
+  With this command, you can specify how the URL path should be matched
+  against incoming requests.
+
+  The available options for <match> are:
+   * ``begin`` Matches the beginning of the URL path
+   * ``end`` Matches the end of the URL path.
+   * ``exact`` Requires an exactly match of the URL path
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> rule <rule>
+   set backend <name>
+
+  Assign a specific backend to a rule
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy service <name> rule <rule>
+   redirect-location <url>
+
+  Redirect URL to a new location
+
+```
+
+### Backend
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> balance
+   <balance>
+
+  Load-balancing algorithms to be used for distributed requests among the
+  available servers
+
+  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
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> mode
+   <mode>
+
+  Configure backend `<name>` mode TCP or HTTP
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> server
+   <name> address <x.x.x.x>
+
+  Set the address of the backend server to which the incoming traffic will
+  be forwarded
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> server
+   <name> port <port>
+
+  Set the address of the backend port
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> server
+   <name> check
+
+  Active health check backend server
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> server
+   <name> send-proxy
+
+  Send a Proxy Protocol version 1 header (text format)
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> server
+   <name> send-proxy-v2
+
+  Send a Proxy Protocol version 2 header (binary format)
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> ssl
+   ca-certificate <ca-certificate>
+
+  Configure requests to the backend server to use SSL encryption and
+  authenticate backend against <ca-certificate>
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> ssl no-verify
+
+  Configure requests to the backend server to use SSL encryption without
+  validating server certificate
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name>
+  http-response-headers <header-name> value <header-value>
+
+  Set custom HTTP headers to be included in all responses using the backend
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy 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 syslog configuration section.
+
+```
+
+### Global
+
+Global parameters
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy global-parameters max-connections
+   <num>
+
+  Limit maximum number of connections
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy global-parameters ssl-bind-ciphers
+   <ciphers>
+
+  Limit allowed cipher algorithms used during SSL/TLS handshake
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy global-parameters tls-version-min
+   <version>
+
+  Specify the minimum required TLS version 1.2 or 1.3
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy 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 syslog configuration section.
+```
+
+## Health checks
+
+### HTTP checks
+
+For web application providing information about their state HTTP health
+checks can be used to determine their availability.
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> http-check
+
+  Enables HTTP health checks using OPTION HTTP requests against '/' and
+  expecting a successful response code in the 200-399 range.
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> http-check
+   method <method>
+
+  Sets the HTTP method to be used, can be either: option, get, post, put
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> http-check
+   uri <path>
+
+  Sets the endpoint to be used for health checks
+```
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> http-check
+   expect <condition>
+
+  Sets the expected result condition for considering a server healthy.
+
+  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
+
+Health checks can also be configured for TCP mode backends. You can configure
+protocol aware checks for a range of Layer 7 protocols:
+
+```{eval-rst}
+.. cfgcmd:: set load-balancing reverse-proxy backend <name> health-check <protocol>
+
+  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 be checked but do not configure a
+protocol, a basic TCP health check will be attempted. A server shall be
+deemed online if it responses to a connection attempt with a valid
+`SYN/ACK` packet.
+:::
+
+## Redirect HTTP to HTTPS
+
+Configure the load-balancing reverse-proxy service for HTTP.
+
+This configuration listen on port 80 and redirect incoming
+requests to HTTPS:
+
+```none
+set load-balancing reverse-proxy service http port '80'
+set load-balancing reverse-proxy service http redirect-http-to-https
+```
+
+The name of the service can be different, in this example it is only 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 will be load balanced across the backend
+servers (srv01 and srv02) using the round-robin load-balancing algorithm.
+
+```none
+set load-balancing reverse-proxy service my-tcp-api backend 'bk-01'
+set load-balancing reverse-proxy service my-tcp-api mode 'tcp'
+set load-balancing reverse-proxy service my-tcp-api port '8888'
+
+set load-balancing reverse-proxy backend bk-01 balance 'round-robin'
+set load-balancing reverse-proxy backend bk-01 mode 'tcp'
+
+set load-balancing reverse-proxy backend bk-01 server srv01 address '192.0.2.11'
+set load-balancing reverse-proxy backend bk-01 server srv01 port '8881'
+set load-balancing reverse-proxy backend bk-01 server srv02 address '192.0.2.12'
+set load-balancing reverse-proxy 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 listen on TCP port 80.
+
+Rule 10 matches requests with the domain name `node1.example.com` forwards
+to the backend `bk-api-01`
+
+Rule 20 matches requests with the domain name `node2.example.com` forwards
+to the backend `bk-api-02`
+
+```none
+set load-balancing reverse-proxy service http description 'bind app listen on 443 port'
+set load-balancing reverse-proxy service http mode 'tcp'
+set load-balancing reverse-proxy service http port '80'
+
+set load-balancing reverse-proxy service http rule 10 domain-name 'node1.example.com'
+set load-balancing reverse-proxy service http rule 10 set backend 'bk-api-01'
+set load-balancing reverse-proxy service http rule 20 domain-name 'node2.example.com'
+set load-balancing reverse-proxy service http rule 20 set backend 'bk-api-02'
+
+set load-balancing reverse-proxy backend bk-api-01 description 'My API-1'
+set load-balancing reverse-proxy backend bk-api-01 mode 'tcp'
+set load-balancing reverse-proxy backend bk-api-01 server api01 address '127.0.0.1'
+set load-balancing reverse-proxy backend bk-api-01 server api01 port '4431'
+set load-balancing reverse-proxy backend bk-api-02 description 'My API-2'
+set load-balancing reverse-proxy backend bk-api-02 mode 'tcp'
+set load-balancing reverse-proxy backend bk-api-02 server api01 address '127.0.0.2'
+set load-balancing reverse-proxy backend bk-api-02 server api01 port '4432'
+```
+
+### Terminate SSL
+
+The following configuration terminates SSL on the router.
+
+The `http` service is listens on port 80 and force redirects from HTTP to
+HTTPS.
+
+The `https` service listens on port 443 with backend `bk-default` to
+handle HTTPS traffic. It uses certificate named `cert` for SSL termination.
+HSTS header is set with a 1-year expiry, to tell browsers to always use SSL for site.
+
+Rule 10 matches requests with the exact URL path `/.well-known/xxx`
+and redirects to location `/certs/`.
+
+Rule 20 matches requests with URL paths ending in `/mail` or exact
+path `/email/bar` redirect to location `/postfix/`.
+
+Additional global parameters are set, including the maximum number
+connection limit of 4000 and a minimum TLS version of 1.3.
+
+```none
+set load-balancing reverse-proxy service http description 'Force redirect to HTTPS'
+set load-balancing reverse-proxy service http port '80'
+set load-balancing reverse-proxy service http redirect-http-to-https
+
+set load-balancing reverse-proxy service https backend 'bk-default'
+set load-balancing reverse-proxy service https description 'listen on 443 port'
+set load-balancing reverse-proxy service https mode 'http'
+set load-balancing reverse-proxy service https port '443'
+set load-balancing reverse-proxy service https ssl certificate 'cert'
+set load-balancing reverse-proxy service https http-response-headers Strict-Transport-Security value 'max-age=31536000'
+
+set load-balancing reverse-proxy service https rule 10 url-path exact '/.well-known/xxx'
+set load-balancing reverse-proxy service https rule 10 set redirect-location '/certs/'
+set load-balancing reverse-proxy service https rule 20 url-path end '/mail'
+set load-balancing reverse-proxy service https rule 20 url-path exact '/email/bar'
+set load-balancing reverse-proxy service https rule 20 set redirect-location '/postfix/'
+
+set load-balancing reverse-proxy backend bk-default description 'Default backend'
+set load-balancing reverse-proxy backend bk-default mode 'http'
+set load-balancing reverse-proxy backend bk-default server sr01 address '192.0.2.23'
+set load-balancing reverse-proxy backend bk-default server sr01 port '80'
+
+set load-balancing reverse-proxy global-parameters max-connections '4000'
+set load-balancing reverse-proxy 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 to the backend server via HTTPS.
+This is useful if encryption is required for both legs, 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 reverse-proxy service https backend 'bk-bridge-ssl'
+set load-balancing reverse-proxy service https description 'listen on 443 port'
+set load-balancing reverse-proxy service https mode 'http'
+set load-balancing reverse-proxy service https port '443'
+set load-balancing reverse-proxy service https ssl certificate 'cert'
+
+set load-balancing reverse-proxy backend bk-bridge-ssl description 'SSL backend'
+set load-balancing reverse-proxy backend bk-bridge-ssl mode 'http'
+set load-balancing reverse-proxy backend bk-bridge-ssl ssl ca-certificate 'cacert'
+set load-balancing reverse-proxy backend bk-bridge-ssl server sr01 address '192.0.2.23'
+set load-balancing reverse-proxy backend bk-bridge-ssl server sr01 port '443'
+```
+
+### Balancing with HTTP health checks
+
+This configuration enables HTTP health checks on backend servers.
+
+```none
+set load-balancing reverse-proxy service my-tcp-api backend 'bk-01'
+set load-balancing reverse-proxy service my-tcp-api mode 'tcp'
+set load-balancing reverse-proxy service my-tcp-api port '8888'
+
+set load-balancing reverse-proxy backend bk-01 balance 'round-robin'
+set load-balancing reverse-proxy backend bk-01 mode 'tcp'
+
+set load-balancing reverse-proxy backend bk-01 http-check method 'get'
+set load-balancing reverse-proxy backend bk-01 http-check uri '/health'
+set load-balancing reverse-proxy backend bk-01 http-check expect 'status 200'
+
+set load-balancing reverse-proxy backend bk-01 server srv01 address '192.0.2.11'
+set load-balancing reverse-proxy backend bk-01 server srv01 port '8881'
+set load-balancing reverse-proxy backend bk-01 server srv01 check
+set load-balancing reverse-proxy backend bk-01 server srv02 address '192.0.2.12'
+set load-balancing reverse-proxy backend bk-01 server srv02 port '8882'
+set load-balancing reverse-proxy backend bk-01 server srv02 check
+```