Function introduction and configuration illustration of F5 Server Load balancer

Based on the huge network structure, the use of cluster servers brings a lot of traffic and other load problems. In contrast, Server Load balancer technology has also emerged. Every technology requires Product Support. Now let's get to know one of F5 Server Load balancer. First, we will introduce the structure and functions of the product.

Many vendors have launched load balancers dedicated to balancing server loads, such as F5 network's BIG-IP, Citrix's NetScaler. F5 BIG-IP ltm's official name is local traffic manager, layer-4-7 Server Load balancer is supported, server Load balancer, application switching, session switching, status monitoring, smart network address translation, General persistence, response error handling, IPv6 gateway, advanced routing, smart port image, SSL Acceleration, smart HTTP compression, TCP optimization, 7th layer rate shaping, content buffering, content conversion, connection acceleration, high-speed cache, Cookie encryption, selective content encryption, application attack filtering, DoS) attack and SYN
Flood Protection, firewall-packet filtering, packet disinfection, and other functions ｡

The following are the main features of F5 BIG-IP as an HTTP Load balancer:

① F5 BIG-IP provides 12 flexible algorithms to distribute all traffic evenly to each server, but to the user, just a virtual server ｡

(2) F5 BIG-IP can confirm whether the application can return the corresponding data to the request. If a server behind the F5 BIG-IP has a service stop, crash and other faults, f5 checks and marks the server as down, so that user access requests are not sent to the faulty server. As long as other servers are normal, user access will not be affected. Once the downtime is fixed, the F5 BIG-IP will automatically verify that the application has responded correctly to the customer request and resume delivery to the server ｡

F5 BIG-IP with dynamic session persistence function ｡

④ F5 BIG-IP irules function can do HTTP content filtering, according to different domain name, URL, the access request is sent to different servers ｡

Below, configure the F5 BIG-IP ltm v9.x Load balancer with instance:

①. Assume that the domain name blog.s135.com is resolved to the Internet/Internet virtual IP address of the F5 Server Load balancer: 61.1.1.3 (vs_squid), and there is a server pool (pool_squid) under the virtual IP address ), the server pool contains two real Squid servers (192.168.1.11 and 192.168.1.12 )｡

② If the Squid cache is not hit, the system will request F5's intranet virtual IP Address: 192.168.1.3 (vs_apache), which has a default server pool (pool_apache_default ), the server pool contains two real Apache servers (192.168.1.21 and 192.168.1.22). When the virtual IP address matches the iRules rule, it will access another server pool (pool_apache_irules ), the server pool also contains two real Apache servers (192.168.1.23 and 192.168.1.24 )｡

③ In addition, the default gateways of all real servers point to the internal network IP address of the F5 Server Load balancer, that is, 192.168.1.2 ｡

④ All real servers access the Internet through the snat ip address 61.1.1.4 ｡