Route health injection

The Route Health Injection (RHI) service interacts with the BIRD Internet Routing Daemon to start or stop the flow of traffic to this HAProxy Enterprise node depending on the health of the network and your load balanced servers. RHI is useful for scaling out an HAProxy Enterprise cluster in an active/active manner, ensuring high availability by relying on well established routing network protocols.

The RHI service adds this HAProxy Enterprise node as a route in BIRD’s configuration using a custom route table named volatile. BIRD then broadcasts these routes to peer routers using the BGP, RIP, or OSPF protocol. If either a frontend or a backend is down, then the RHI service removes the route from the volatile table, notifying BIRD to stop advertising this HAProxy Enterprise node as a route on the network, diverting the flow of traffic to the other HAProxy Enterprise node in the active-active cluster. You can configure ECMP on your router to load balance traffic to both HAProxy Enterprise nodes via the advertised routes.

Configure Route Health Injection Jump to heading #

1. Install the RHI module using your package manager:

   apt yum zypper pkg

   nix
   sudo apt-get install hapee-extras-rhi

   nix
   sudo apt-get install hapee-extras-rhi

   nix
   sudo yum install hapee-extras-rhi

   nix
   sudo yum install hapee-extras-rhi

   nix
   sudo zypper install hapee-extras-rhi

   nix
   sudo zypper install hapee-extras-rhi

   nix
   sudo pkg install hapee-extras-rhi

   nix
   sudo pkg install hapee-extras-rhi

   This installs the hapee-extras-route package too, which is our version of the BIRD Internet Routing Daemon. The daemon is stored as /opt/hapee-extras/sbin/hapee-route.

2. Create a socket for the Runtime API.

   The RHI service needs to connect to the Runtime API to collect information about the health of your frontends and backends. Add a new stats socket line to the global section of your HAProxy Enterprise configuration. This exposes the Runtime API as the socket /var/run/hapee-extras/hapee-lb.sock:

   haproxy
   global
     stats socket /var/run/hapee-extras/hapee-lb.sock user hapee-lb group hapee mode 660

   haproxy
   global
     stats socket /var/run/hapee-extras/hapee-lb.sock user hapee-lb group hapee mode 660

3. Configure the RHI service.

   • Edit the file /etc/hapee-extras/hapee-rhi.cfg.

     The default configuration contains an example:

     hapee-rhi.cfg
     text
     # Inject the 10.200.200.200/32 address into the route daemon if
     # all the backends "be_static" and "be_app" are up.
     10.200.200.200/32 = all(b:be_static,b:be_app)

     hapee-rhi.cfg
     text
     # Inject the 10.200.200.200/32 address into the route daemon if
     # all the backends "be_static" and "be_app" are up.
     10.200.200.200/32 = all(b:be_static,b:be_app)

     This file contains a list of routes that the RHI service should add to BIRD, but only if a given rule returns true; a rule checks the status of one or more frontends or backends to see if they are up or down. A backend is treated as down if all servers fail their health checks or if you manually disable the servers. A frontend is down if you disable it manually.

     For example, the following line uses the all rule to announce the 192.168.1.10/32 IP only when both the be_static and be_app backend are up and running. When the condition is false, the IP is removed from the list of advertised routes:

     hapee-rhi.cfg
     text
     192.168.1.10/32 = all(b:be_static,b:be_app)

     hapee-rhi.cfg
     text
     192.168.1.10/32 = all(b:be_static,b:be_app)

     Or, the following line uses the any rule to advertise the IP if either the be_app or be_app2 backends are up and running:

     hapee-rhi.cfg
     text
     192.168.1.10/32 = any(b:be_app,b:be_app2)

     hapee-rhi.cfg
     text
     192.168.1.10/32 = any(b:be_app,b:be_app2)

   • Save the configuration and then enable and restart the service:

     nix
     sudo systemctl enable hapee-extras-rhi
     sudo systemctl restart hapee-extras-rhi

     nix
     sudo systemctl enable hapee-extras-rhi
     sudo systemctl restart hapee-extras-rhi

4. Add iptables rules to route traffic to the HAProxy Enterprise socket:

   nix
   sudo iptables -t mangle -N DIVERT
   sudo iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT
   sudo iptables -t mangle -A DIVERT -j MARK --set-mark 1
   sudo iptables -t mangle -A DIVERT -j ACCEPT

   nix
   sudo iptables -t mangle -N DIVERT
   sudo iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT
   sudo iptables -t mangle -A DIVERT -j MARK --set-mark 1
   sudo iptables -t mangle -A DIVERT -j ACCEPT

5. Edit the HAProxy Enterprise configuration file, /etc/hapee-2.8/hapee-lb.cfg:

   • In the frontend section, change the addresses on the bind lines so that they use a new IP address that is not yet assigned to one of the network interfaces.

   • Because the IP addresses are not actually configured on the network interface, configure transparent binding by adding the transparent argument to the bind lines. This indicates that the IP address should be bound even though it does not belong to the local machine. Packets targeting this address will be intercepted as if the address were locally configured. This feature uses the kernel’s TPROXY feature, which has been available since Linux kernel 2.2.

   haproxy
   frontend www
     bind 192.168.1.10:80 name http transparent
     bind 192.168.1.10:443 name https ssl crt site.pem transparent

   haproxy
   frontend www
     bind 192.168.1.10:80 name http transparent
     bind 192.168.1.10:443 name https ssl crt site.pem transparent

6. Save the changes and then restart the service.

   nix
   sudo systemctl reload hapee-2.8-lb

   nix
   sudo systemctl reload hapee-2.8-lb

   Each HAProxy Enterprise node should be assigned the same IP address.

7. Configure BIRD for BGP or OSPF, which are used to advertise routes to peer routers.

   • Edit the file /etc/hapee-extras/hapee-route.cfg.

   • Add a section for either BGP or OSPF, depending on which protocol you intend to use for advertising routes to peers. Within it, add an export line that advertises routes from the volatile table, vol1.

     An example BGP configuration section:

     hapee-route.cfg
     text
       protocol bgp r1 {
       local 192.168.0.101 as 65001;
       neighbor 192.168.0.1 as 65001;
       graceful restart on;
       import none;
       
       # advertise the IP route
       export where proto = "vol1";
     }

     hapee-route.cfg
     text
       protocol bgp r1 {
       local 192.168.0.101 as 65001;
       neighbor 192.168.0.1 as 65001;
       graceful restart on;
       import none;
       
       # advertise the IP route
       export where proto = "vol1";
     }

     In this example:

     • the local directive refers to the IP address assigned to this HAProxy Enterprise node’s network interface and assigns the Autonomous System Number 65001.
     • the neighbor directive refers to the layer 3 device, such as the gateway router, with which we are establishing a BGP session.
     • the neighbor directive refers to the layer 3 device, such as the gateway router, with which we are establishing a BGP session.

     An example OSPF configuration section:

     hapee-route.cfg
     text
     protocol ospf anycast {
       tick 2;
       import none;
       
       # advertise the IP route
       export where proto = "vol1";
       
       area 0.0.0.0 {
         stub no;
         interface "eth0" {
            hello 10;
            retransmit 6;
            cost 10;
            transmit delay 5;
            dead count 4;
            wait 50;
            type broadcast;
         };
       };
     }

     hapee-route.cfg
     text
     protocol ospf anycast {
       tick 2;
       import none;
       
       # advertise the IP route
       export where proto = "vol1";
       
       area 0.0.0.0 {
         stub no;
         interface "eth0" {
            hello 10;
            retransmit 6;
            cost 10;
            transmit delay 5;
            dead count 4;
            wait 50;
            type broadcast;
         };
       };
     }

   • Save the configuration and then restart the service:

     nix
     sudo systemctl restart hapee-extras-route

     nix
     sudo systemctl restart hapee-extras-route

   • Repeat these steps for the hapee-extras-route6 service if using IPv6.

8. Verify that RHI added a route to BIRD by calling the show route command. The IP should display.

   nix
   sudo /opt/hapee-extras/bin/hapee-route-cli show route

   nix
   sudo /opt/hapee-extras/bin/hapee-route-cli show route

   output
   text
   BIRD 1.6.3 ready.
   192.168.1.10/32    dev auto [vol1 18:54:15] * (0)

   output
   text
   BIRD 1.6.3 ready.
   192.168.1.10/32    dev auto [vol1 18:54:15] * (0)

   When you disable all servers in the backend, the command should not return this route.

9. Configure ECMP on your peer router to distribute traffic to the bound IP.

Volatile table Jump to heading #

BIRD stores routes in routing tables, with each table associated with a particular protocol such as BGP or OSPF. The RHI service adds its own table named volatile, which allows it to add routes to BIRD dynamically.

To see the volatile table definition, edit the BIRD configuration.

1. Edit the file /etc/hapee-extras/hapee-route.cfg.

2. Scroll down to the protocol volatile section.

   hapee-route.cfg
   text
   protocol volatile vol1 {
     #  gateway <ip>
   }

   hapee-route.cfg
   text
   protocol volatile vol1 {
     #  gateway <ip>
   }

   By default, BIRD announces routes through the gateway configured on the network interface, but you can specify a different network gateway by uncommenting the gateway directive and typing its IP address.

   For example:

   hapee-route.cfg
   text
   protocol volatile vol1 {
     gateway 192.168.1.244
   }

   hapee-route.cfg
   text
   protocol volatile vol1 {
     gateway 192.168.1.244
   }

   You can add more volatile tables to support advertising routes for different frontends:

   hapee-route.cfg
   text
   protocol volatile vol1 {
   }
   protocol volatile vol2 {
   }

   hapee-route.cfg
   text
   protocol volatile vol1 {
   }
   protocol volatile vol2 {
   }

   Then, prefix each route in the RHI service’s configuration, /etc/hapee-extras/hapee-rhi.cfg, with a table’s name:

   hapee-rhi.cfg
   text
   vol1%192.168.1.10/32 = all(b:be_static,b:be_app)
   vol2%192.168.1.11/32 = any(b:k8s_servers)

   hapee-rhi.cfg
   text
   vol1%192.168.1.10/32 = all(b:be_static,b:be_app)
   vol2%192.168.1.11/32 = any(b:k8s_servers)

Rules syntax Jump to heading #

This section describes the syntax of the RHI configuration file.

text
<network>[,<network>,[...]] = <agg>(<b:|f:><name>[,<b:|f:><name>,[...]])

text
<network>[,<network>,[...]] = <agg>(<b:|f:><name>[,<b:|f:><name>,[...]])

See also Jump to heading #

• The BIRD Internet Routing Daemon
• transparent reference