This appendix describes how to set up a 2-tier, high availability configuration combining the capabilities of two Load Balancer components (the Dispatcher component and the CBR component) along with Caching Proxy.
The server machine set up for Figure 43 is the following:
Figure 43 shows a basic representation of multiple servers (EdgeServer1, EdgeServer2, EdgeServer3) load balancing across multiple backend Web servers. The CBR component uses Caching Proxy to forward requests based on the content of the URL to the backend Web servers. The Dispatcher component is used to load balance the CBR components across the EdgeServers. The high availability feature of the Dispatcher component is used to ensure that requests to the backend servers continue even if the primary high availability machine (EdgeServer1) fails at any time.
Basic Configuration Guidelines:
Caching ON
CacheMemory 128000 K
ReversePass /* http://websrvA.company.com/* http://www.company.com/*
Sample Configuration Files:
The following sample configuration files are similar to files that are created when setting up an Edge Components configuration as shown in Figure 43. The sample configuration files represent the files for the Dispatcher and CBR components of Load Balancer. In the sample configuration, a single Ethernet adapter is used for each of the EdgeServer machines and all addresses are represented within a private subnet. The sample configuration files use the following IP addresses for the specified machines:
Sample Configuration file for Dispatcher component on Primary high availability EdgeServer:
dscontrol executor start
dscontrol cluster add 192.168.1.11 primaryhost 192.168.1.10
dscontrol port add 192.168.1.11:80
dscontrol server add 192.168.1.11:80:edgeserver1 address 192.168.1.10
dscontrol server add 192.168.1.11:80:edgeserver2 address 192.168.1.20
dscontrol server add 192.168.1.11:80:edgeserver3 address 192.168.1.30
dscontrol manager start manager.log 10004
dscontrol highavailability heartbeat add 192.168.1.10 192.168.1.20
dscontrol highavailability backup add primary auto 4567
Sample Configuration file for CBR component on the EdgeServers:
cbrcontrol set loglevel 1
cbrcontrol executor start
cbrcontrol cluster add 192.168.1.11
cbrcontrol port add 192.168.1.11:80
cbrcontrol server add 192.168.1.11:80:webserverA address 192.168.1.71
cbrcontrol server add 192.168.1.11:80:webserverB address 192.168.1.72
cbrcontrol server add 192.168.1.11:80:webserverC address 192.168.1.73
cbrcontrol rule add 192.168.1.11:80:webA_rule type content
pattern (URI=*WSA*)|(URI=*wsA*) priority 21
cbrcontrol rule useserver 192.168.1.11:80:webA_rule webserverA
cbrcontrol rule add 192.168.1.11:80:webB_rule type content
pattern (URI=/WS_B*) priority 22
cbrcontrol rule useserver 192.168.1.11:80:webB_rule webserverB
cbrcontrol rule add 192.168.1.11:80:webC_rule type content
pattern URI=*webC* priority 23
cbrcontrol rule useserver 192.168.1.21:80:webC_rule webserverC