Varnish 负载均衡后端服务器定义后端主机列表：
vim /etc/varnish/default.vcl
# Default backend definition. Set this to point toyour content server.
backend websrv1 {
.host ="192.168.2.223";
.port ="80";
.probe = {
.url ="/index.htm";
}
}
backend websrv2 {
.host ="192.168.2.224";
.port ="80";
.probe = {
.url ="/index.htm";
}
}
import directors; #导入directors
#[root@node230 varnish]# man vmod_directors 配置命令详解
sub vcl_init {
newmycluster = directors.round_robin(); #定义集群,后端服务器轮询
mycluster.add_backend(websrv1);
mycluster.add_backend(websrv2);
}
sub vcl_recv {
set req.backend_hint = mycluster.backend();
}
动态加载vcl文件：
[root@node230 ~]# varnishadm -S /etc/varnish/secret -T192.168.2.230:6082
vcl.list
200
active 0boot
vcl.load test2 test.vcl
200
VCL compiled.
vcl.use test2
200
VCL 'test2' now active
vcl.list
200
available 0boot
active 0test2
在varnish服务器上可以看到负载均衡器效果：
一个请求同时到后端两台服务器上去取数据
varnishd 24295 varnish 26u IPv4 736836 0t0 TCP node230:52496->192.168.2.223:http(ESTABLISHED
)
varnishd 24295varnish 27u IPv4 736837 0t0 TCP node230:45026->192.168.2.224:http(ESTABLISHED
)
varnishd 24295varnish 28u IPv4 736838 0t0 TCP node230:52500->192.168.2.223:http(ESTABLISHED
)
varnishd 24295varnish 29u IPv4 736839 0t0 TCP node230:45030->192.168.2.224:http(ESTABLISHED
)
负载均衡算法
sub vcl_init {
new mycluster = directors.round_robin(); #定义集群,后端服务器轮询
mycluster.add_backend(websrv1);
mycluster.add_backend(websrv2);
}
其它算法：
fallback
random
round_robin
hash
