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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/configuration/loadbalancing/index.rst | 319 | ||||
| -rw-r--r-- | docs/configuration/loadbalancing/reverse-proxy.rst | 289 | ||||
| -rw-r--r-- | docs/configuration/loadbalancing/wan.rst | 315 |
3 files changed, 612 insertions, 311 deletions
diff --git a/docs/configuration/loadbalancing/index.rst b/docs/configuration/loadbalancing/index.rst index 18f01347..382bd0d7 100644 --- a/docs/configuration/loadbalancing/index.rst +++ b/docs/configuration/loadbalancing/index.rst @@ -1,315 +1,12 @@ -:lastproofread: 2023-01-27 - .. _load-balancing: -WAN load balancing -================== - -Outbound traffic can be balanced between two or more outbound interfaces. -If a path fails, traffic is balanced across the remaining healthy paths, -a recovered path is automatically added back to the routing table and used by -the load balancer. The load balancer automatically adds routes for each path to -the routing table and balances traffic across the configured interfaces, -determined by 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). - -Let's assume we have two DHCP WAN interfaces and one LAN (eth2): - -.. code-block:: 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:: - - WAN Load Balacing should not be used when dynamic routing protocol is - used/needed. This feature creates customized routing tables and firewall - rules, that makes it incompatible to use with routing protocols. - -Balancing Rules ---------------- - -Interfaces, their weight and the type of traffic to be balanced are defined in -numbered balancing rule sets. The rule sets are executed in numerical order -against outgoing packets. In case of a match the packet is sent through an -interface specified in the matching rule. If a packet doesn't match any rule -it is sent by using the system routing table. Rule numbers can't be changed. - -Create a load balancing rule, it can be a number between 1 and 9999: - -.. code-block:: 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 -**************** - -Let's expand the example from above and add weight to the interfaces. -The bandwidth from eth0 is larger than eth1. Per default, outbound traffic is -distributed randomly across available interfaces. Weights can be assigned to -interfaces to influence the balancing. - -.. code-block:: none - - set load-balancing wan rule 1 interface eth0 weight 2 - set load-balancing wan rule 1 interface eth1 weight 1 - -66% of traffic is routed to eth0, eth1 gets 33% of traffic. - -Rate limit -********** - -A packet rate limit can be set for a rule to apply the rule to traffic above or -below a specified threshold. To configure the rate limiting use: - -.. code-block:: 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 -******************************* - -Outgoing traffic is balanced in a flow-based manner. -A connection tracking table is used to track flows by their source address, -destination address and port. Each flow is assigned to an interface according -to the defined balancing rules and subsequent packets are sent through the -same interface. This has the advantage that packets always arrive in order if -links with different speeds are in use. - -Packet-based balancing can lead to a better balance across interfaces when out -of order packets are no issue. Per-packet-based balancing can be set for a -balancing rule with: - -.. code-block:: none - - set load-balancing wan rule <rule> per-packet-balancing - -Exclude traffic -*************** - -To exclude traffic from load balancing, traffic matching an exclude rule is not -balanced but routed through the system routing table instead: - -.. code-block:: none - - set load-balancing wan rule <rule> exclude - - -Health checks -------------- - -The health of interfaces and paths assigned to the load balancer is -periodically checked by sending ICMP packets (ping) to remote destinations, -a TTL test or the execution of a user defined script. If an interface fails the -health check it is removed from the load balancer's pool of interfaces. -To enable health checking for an interface: - -.. code-block:: 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 nexthop on the path to the destination, ``ipv4-address`` can be set to -``dhcp`` - -.. code-block:: none - - set load-balancing wan interface-health <interface> nexthop <ipv4-address> - -Set the number of health check failures before an interface is marked as -unavailable, range for number is 1 to 10, default 1. Or set the number of -successful health checks before an interface is added back to the interface -pool, range for number is 1 to 10, default 1. - -.. code-block:: none - - set load-balancing wan interface-health <interface> failure-count <number> - set load-balancing wan interface-health <interface> success-count <number> - -Each health check is configured in its own test, tests are numbered and -processed in numeric order. For multi target health checking multiple tests -can be defined: - -.. code-block:: 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 be sent ICMP packets to, address can be an IPv4 - address or hostname -* ``test-script``: A user defined script must return 0 to be considered - successful and non-zero to fail. Scripts are located in /config/scripts, - for different locations the full path needs to be provided -* ``ttl-limit``: For the UDP TTL limit test the hop count limit must be - specified. The limit must be shorter than the path length, an ICMP time - expired message is needed to be returned for a successful test. default 1 -* ``type``: Specify the type of test. type can be ping, ttl or a user defined - script - -Source NAT rules ----------------- - -Per default, interfaces used in a load balancing pool replace the source IP -of each outgoing packet with its own address to ensure that replies arrive on -the same interface. This works through automatically generated source NAT (SNAT) -rules, these rules are only applied to balanced traffic. In cases where this -behaviour is not desired, the automatic generation of SNAT rules can be -disabled: - -.. code-block:: none - - set load-balancing wan disable-source-nat - -Sticky Connections ------------------- -Inbound connections to a WAN interface can be improperly handled when the reply -is sent back to the client. - -.. image:: /_static/images/sticky-connections.jpg - :width: 80% - :align: center - - -Upon reception of an incoming packet, when a response is sent, it might be -desired to ensure that it leaves from the same interface as the inbound one. -This can be achieved by enabling sticky connections in the load balancing: - -.. code-block:: none - - set load-balancing wan sticky-connections inbound - -Failover --------- - -In failover mode, one interface is set to be the primary interface and other -interfaces are secondary or spare. Instead of balancing traffic across all -healthy interfaces, only the primary interface is used and in case of failure, -a secondary interface selected from the pool of available interfaces takes over. -The primary interface is selected based on its weight and health, others become -secondary interfaces. Secondary interfaces to take over a failed primary -interface are chosen from the load balancer's interface pool, depending -on their weight and health. Interface roles can also be selected based on rule -order by including interfaces in balancing rules and ordering those rules -accordingly. To put the load balancer in failover mode, create a failover rule: - -.. code-block:: none - - set load-balancing wan rule <number> failover - -Because existing sessions do not automatically fail over to a new path, -the session table can be flushed on each connection state change: - -.. code-block:: none - - set load-balancing wan flush-connections - -.. warning:: - - Flushing the session table will cause other connections to fall back from - flow-based to packet-based balancing until each flow is reestablished. - -Script execution ----------------- - -A script can be run when an interface state change occurs. Scripts are run -from /config/scripts, for a different location specify the full path: - -.. code-block:: 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. System will become unresponsive if script - does not return! - -Handling and monitoring ------------------------ - - -Show WAN load balancer information including test types and targets. -A character at the start of each line depicts the state of the test - -* ``+`` successful -* ``-`` failed -* a blank indicates that no test has been carried out - -.. code-block:: 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: - -.. code-block:: 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 -******* +############## +Load-balancing +############## -.. code-block:: none +.. toctree:: + :maxdepth: 1 + :includehidden: - restart wan-load-balance + wan + reverse-proxy diff --git a/docs/configuration/loadbalancing/reverse-proxy.rst b/docs/configuration/loadbalancing/reverse-proxy.rst new file mode 100644 index 00000000..24f26af0 --- /dev/null +++ b/docs/configuration/loadbalancing/reverse-proxy.rst @@ -0,0 +1,289 @@ + +.. _load-balancing: + +############# +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 +------- + +.. 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 + +.. cfgcmd:: set load-balancing reverse-proxy service <name> port + <port> + + Create service `<name>` to listen on <port> + +.. cfgcmd:: set load-balancing reverse-proxy service <name> mode + <tcp|http> + + Configure service `<name>` mode TCP or HTTP + +.. cfgcmd:: set load-balancing reverse-proxy service <name> backend + <name> + + Configure service `<name>` to use the backend <name> + +.. cfgcmd:: set load-balancing reverse-proxy service <name> ssl + certificate <name> + + Set SSL certeficate <name> for service <name> + + +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. + +.. cfgcmd:: set load-balancing reverse-proxy service <name> rule <rule> + domain-name <name> + + Match domain name + +.. 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 + +.. 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 + +.. cfgcmd:: set load-balancing reverse-proxy service <name> rule <rule> + set backend <name> + + Assign a specific backend to a rule + +.. cfgcmd:: set load-balancing reverse-proxy service <name> rule <rule> + redirect-location <url> + + Redirect URL to a new location + + +Backend +------- + +.. cfgcmd:: set load-balancing reverse-proxy backend <name> balance + <balance> + + Load-balancing algorithms to be used for distributind requests among the + vailable 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 tp tje server wotj the fewest + active connections + +.. cfgcmd:: set load-balancing reverse-proxy backend <name> mode + <mode> + + Configure backend `<name>` mode TCP or HTTP + +.. cfgcmd:: set load-balancing reverse-proxy backend <name> parameters + http-check + + Enable layer 7 HTTP health check + +.. 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 + +.. cfgcmd:: set load-balancing reverse-proxy backend <name> server + <name> port <port> + + Set the address of the backend port + +.. cfgcmd:: set load-balancing reverse-proxy backend <name> server + <name> check + + Active health check backend server + +.. cfgcmd:: set load-balancing reverse-proxy backend <name> server + <name> send-proxy + + Send a Proxy Protocol version 1 header (text format) + +.. cfgcmd:: set load-balancing reverse-proxy backend <name> server + <name> send-proxy-v2 + + Send a Proxy Protocol version 2 header (binary format) + + + +Gloabal +------- + +Global parameters + +.. cfgcmd:: set load-balancing reverse-proxy global-parameters max-connections + <num> + + Limit maximum number of connections + +.. cfgcmd:: set load-balancing reverse-proxy global-parameters ssl-bind-ciphers + <ciphers> + + Limit allowed cipher algorithms used during SSL/TLS handshake + +.. cfgcmd:: set load-balancing reverse-proxy global-parameters tls-version-min + <version> + + Specify the minimum required TLS version 1.2 or 1.3 + + +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: + +.. code-block:: 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. + +.. code-block:: 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`` + +.. code-block:: 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 reverse-proxy terminate SSL. + +The ``http`` service is lestens 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. + +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. + + +.. code-block:: 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 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' + diff --git a/docs/configuration/loadbalancing/wan.rst b/docs/configuration/loadbalancing/wan.rst new file mode 100644 index 00000000..18f01347 --- /dev/null +++ b/docs/configuration/loadbalancing/wan.rst @@ -0,0 +1,315 @@ +:lastproofread: 2023-01-27 + +.. _load-balancing: + +WAN load balancing +================== + +Outbound traffic can be balanced between two or more outbound interfaces. +If a path fails, traffic is balanced across the remaining healthy paths, +a recovered path is automatically added back to the routing table and used by +the load balancer. The load balancer automatically adds routes for each path to +the routing table and balances traffic across the configured interfaces, +determined by 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). + +Let's assume we have two DHCP WAN interfaces and one LAN (eth2): + +.. code-block:: 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:: + + WAN Load Balacing should not be used when dynamic routing protocol is + used/needed. This feature creates customized routing tables and firewall + rules, that makes it incompatible to use with routing protocols. + +Balancing Rules +--------------- + +Interfaces, their weight and the type of traffic to be balanced are defined in +numbered balancing rule sets. The rule sets are executed in numerical order +against outgoing packets. In case of a match the packet is sent through an +interface specified in the matching rule. If a packet doesn't match any rule +it is sent by using the system routing table. Rule numbers can't be changed. + +Create a load balancing rule, it can be a number between 1 and 9999: + +.. code-block:: 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 +**************** + +Let's expand the example from above and add weight to the interfaces. +The bandwidth from eth0 is larger than eth1. Per default, outbound traffic is +distributed randomly across available interfaces. Weights can be assigned to +interfaces to influence the balancing. + +.. code-block:: none + + set load-balancing wan rule 1 interface eth0 weight 2 + set load-balancing wan rule 1 interface eth1 weight 1 + +66% of traffic is routed to eth0, eth1 gets 33% of traffic. + +Rate limit +********** + +A packet rate limit can be set for a rule to apply the rule to traffic above or +below a specified threshold. To configure the rate limiting use: + +.. code-block:: 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 +******************************* + +Outgoing traffic is balanced in a flow-based manner. +A connection tracking table is used to track flows by their source address, +destination address and port. Each flow is assigned to an interface according +to the defined balancing rules and subsequent packets are sent through the +same interface. This has the advantage that packets always arrive in order if +links with different speeds are in use. + +Packet-based balancing can lead to a better balance across interfaces when out +of order packets are no issue. Per-packet-based balancing can be set for a +balancing rule with: + +.. code-block:: none + + set load-balancing wan rule <rule> per-packet-balancing + +Exclude traffic +*************** + +To exclude traffic from load balancing, traffic matching an exclude rule is not +balanced but routed through the system routing table instead: + +.. code-block:: none + + set load-balancing wan rule <rule> exclude + + +Health checks +------------- + +The health of interfaces and paths assigned to the load balancer is +periodically checked by sending ICMP packets (ping) to remote destinations, +a TTL test or the execution of a user defined script. If an interface fails the +health check it is removed from the load balancer's pool of interfaces. +To enable health checking for an interface: + +.. code-block:: 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 nexthop on the path to the destination, ``ipv4-address`` can be set to +``dhcp`` + +.. code-block:: none + + set load-balancing wan interface-health <interface> nexthop <ipv4-address> + +Set the number of health check failures before an interface is marked as +unavailable, range for number is 1 to 10, default 1. Or set the number of +successful health checks before an interface is added back to the interface +pool, range for number is 1 to 10, default 1. + +.. code-block:: none + + set load-balancing wan interface-health <interface> failure-count <number> + set load-balancing wan interface-health <interface> success-count <number> + +Each health check is configured in its own test, tests are numbered and +processed in numeric order. For multi target health checking multiple tests +can be defined: + +.. code-block:: 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 be sent ICMP packets to, address can be an IPv4 + address or hostname +* ``test-script``: A user defined script must return 0 to be considered + successful and non-zero to fail. Scripts are located in /config/scripts, + for different locations the full path needs to be provided +* ``ttl-limit``: For the UDP TTL limit test the hop count limit must be + specified. The limit must be shorter than the path length, an ICMP time + expired message is needed to be returned for a successful test. default 1 +* ``type``: Specify the type of test. type can be ping, ttl or a user defined + script + +Source NAT rules +---------------- + +Per default, interfaces used in a load balancing pool replace the source IP +of each outgoing packet with its own address to ensure that replies arrive on +the same interface. This works through automatically generated source NAT (SNAT) +rules, these rules are only applied to balanced traffic. In cases where this +behaviour is not desired, the automatic generation of SNAT rules can be +disabled: + +.. code-block:: none + + set load-balancing wan disable-source-nat + +Sticky Connections +------------------ +Inbound connections to a WAN interface can be improperly handled when the reply +is sent back to the client. + +.. image:: /_static/images/sticky-connections.jpg + :width: 80% + :align: center + + +Upon reception of an incoming packet, when a response is sent, it might be +desired to ensure that it leaves from the same interface as the inbound one. +This can be achieved by enabling sticky connections in the load balancing: + +.. code-block:: none + + set load-balancing wan sticky-connections inbound + +Failover +-------- + +In failover mode, one interface is set to be the primary interface and other +interfaces are secondary or spare. Instead of balancing traffic across all +healthy interfaces, only the primary interface is used and in case of failure, +a secondary interface selected from the pool of available interfaces takes over. +The primary interface is selected based on its weight and health, others become +secondary interfaces. Secondary interfaces to take over a failed primary +interface are chosen from the load balancer's interface pool, depending +on their weight and health. Interface roles can also be selected based on rule +order by including interfaces in balancing rules and ordering those rules +accordingly. To put the load balancer in failover mode, create a failover rule: + +.. code-block:: none + + set load-balancing wan rule <number> failover + +Because existing sessions do not automatically fail over to a new path, +the session table can be flushed on each connection state change: + +.. code-block:: none + + set load-balancing wan flush-connections + +.. warning:: + + Flushing the session table will cause other connections to fall back from + flow-based to packet-based balancing until each flow is reestablished. + +Script execution +---------------- + +A script can be run when an interface state change occurs. Scripts are run +from /config/scripts, for a different location specify the full path: + +.. code-block:: 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. System will become unresponsive if script + does not return! + +Handling and monitoring +----------------------- + + +Show WAN load balancer information including test types and targets. +A character at the start of each line depicts the state of the test + +* ``+`` successful +* ``-`` failed +* a blank indicates that no test has been carried out + +.. code-block:: 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: + +.. code-block:: 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 +******* + +.. code-block:: none + + restart wan-load-balance |