实战一：
backend websrv1 {
.host = "172.16.100.68";
.port = "80";
.probe = {
.url = "/test1.html";
}
}
backend websrv2 {
.host = "172.16.100.69";
.port = "80";
.probe = {
.url = "/test1.html";
}
}
sub vcl_recv {
if (req.url ~ "(?i)\.(jpg|png|gif)$") {
set req.backend_hint = websrv1;
} else {
set req.backend_hint = websrv2;
}
}
实战二：
import directors;
sub vcl_init {
new mycluster = directors.round_robin();
mycluster.add_backend(websrv1);
mycluster.add_backend(websrv2);
}
vcl_recv {
set req.backend_hint = mycluster.backend();
}
负载均衡算法：
fallback, random, round_robin, hash
补充：
移除单个缓存对象
purge用于清理缓存中的某特定对象及其变种(variants)，因此，在有着明确要修剪的缓存对象时可以使用此种方式。HTTP协议的PURGE方法可以实现purge功能，不过，其仅能用于vcl_hit和vcl_miss中，它会释放内存工作并移除指定缓存对象的所有Vary:-变种，并等待下一个针对此内容的客户端请求到达时刷新此内容。另外，其一般要与return(restart)一起使用。下面是个在VCL中配置的示例。
acl purgers {
"127.0.0.1";
"192.168.0.0"/24;
}
sub vcl_recv {
if (req.request == "PURGE") {
if (!client.ip ~ purgers) {
error 405 "Method not allowed";
}
return (lookup);
}
}
sub vcl_hit {
if (req.request == "PURGE") {
purge;
error 200 "Purged";
}
}
sub vcl_miss {
if (req.request == "PURGE") {
purge;
error 404 "Not in cache";
}
}
sub vcl_pass {
if (req.request == "PURGE") {
error 502 "PURGE on a passed object";
}
}
客户端在发起HTTP请求时，只需要为所请求的URL使用PURGE方法即可，其命令使用方式如下：
# curl -I -X PURGE http://varniship/path/to/someurl
生产环境案例一则：
acl purge {
"localhost";
"127.0.0.1";
"10.1.0.0"/16;
"192.168.0.0"/16;
}
sub vcl_hash {
hash_data(req.url);
return (hash);
}
sub vcl_recv {
set req.backend = shopweb;
# set req.grace = 4h;
if (req.request == "PURGE") {
if (!client.ip ~ purge) {
error 405 "Not allowed.";
}
return(lookup);
}
if (req.request == "REPURGE") {
if (!client.ip ~ purge) {
error 405 "Not allowed.";
}
ban("req.http.host == " + req.http.host + " && req.url ~ " + req.url);
error 200 "Ban OK";
}
if (req.restarts == 0) {
if (req.http.x-forwarded-for) {
set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip;
}
else {
set req.http.X-Forwarded-For = client.ip;
}
}
if (req.request != "GET" &&
req.request != "HEAD" &&
req.request != "PUT" &&
req.request != "POST" &&
req.request != "TRACE" &&
req.request != "OPTIONS" &&
req.request != "DELETE") {
/* Non-RFC2616 or CONNECT which is weird. */
return (pipe);
}
if (req.request != "GET" && req.request != "HEAD") {
/* We only deal with GET and HEAD by default */
return (pass);
}
if (req.http.Authorization) {
/* Not cacheable by default */
return (pass);
}
if ( req.url == "/Heartbeat.html" ) {
return (pipe);
}
if ( req.url == "/" ) {
return (pipe);
}
if ( req.url == "/index.jsp" ) {
return (pipe);
}
if (req.http.Cookie ~ "dper=") {
return (pass);
}
if (req.http.Cookie ~ "sqltrace=") {
return (pass);
}
if (req.http.Cookie ~ "errortrace=") {
return (pass);
}
# if ( req.request == "GET" && req.url ~ "req.url ~ "^/shop/[0-9]+$" ) {
if ( req.url ~ "^/shop/[0-9]+$" || req.url ~ "^/shop/[0-9]?.*" ) {
return (lookup);
}
if ( req.url ~ "^/shop/(\d{1,})/editmember" || req.url ~ "^/shop/(\d{1,})/map" || req.url ~ "^/shop/(\d+)/dish-([^/]+)" ) {
return (lookup);
}
return (pass);
# return (lookup);
}
sub vcl_pipe {
return (pipe);
}
sub vcl_pass {
return (pass);
}
sub vcl_hit {
if (req.request == "PURGE") {
purge;
error 200 "Purged.";
}
return (deliver);
}
sub vcl_miss {
if (req.request == "PURGE") {
error 404 "Not in cache.";
}
# if (object needs ESI processing) {
# unset bereq.http.accept-encoding;
# }
return (fetch);
}
sub vcl_fetch {
set beresp.ttl = 3600s;
set beresp.http.expires = beresp.ttl;
#set beresp.grace = 4h;
# if (object needs ESI processing) {
# set beresp.do_esi = true;
# set beresp.do_gzip = true;
# }
if ( req.url ~ "^/shop/[0-9]+$" || req.url ~ "^/shop/[0-9]?.*" ) {
set beresp.ttl = 4h;
}
if ( req.url ~ "^/shop/(\d{1,})/editmember" || req.url ~ "^/shop/(\d{1,})/map" || req.url ~ "^/shop/(\d+)/dish-([^/]+)" ) {
set beresp.ttl = 24h;
}
if (beresp.status != 200){
return (hit_for_pass);
}
return (deliver);
}
sub vcl_deliver {
if (obj.hits > 0){
set resp.http.X-Cache = "HIT";
}
else {
set resp.http.X-Cache = "MISS";
}
set resp.http.X-Powered-By = "Cache on " + server.ip;
set resp.http.X-Age = resp.http.Age;
return (deliver);
}
sub vcl_error {
set obj.http.Content-Type = "text/html; charset=utf-8";
set obj.http.Retry-After = "5";
synthetic {""} + obj.status + " " + obj.response + {""};
return (deliver);
}
sub vcl_init {
return (ok);
}
sub vcl_fini {
return (ok);
}
补充资料：
varnish的线程模型：
cache-worker线程
cache-main线程：此线程只有一个，用于启动caceh；
ban luker：
acceptor：
epoll：线程池管理器
expire：清理过期缓存
varnish定义其最大并发连接数：线程池模型：
thread_pools：线程池个数；默认为2；
thread_pool_max：单线程池内允许启动的最多线程个数；
thread_pool_min
thread_pool_timeout：多于thread_pool_min的线程空闲此参数指定的时长后即被purge；
varnish的param查看及改变：
param.show [-l] [param]
param.set [param] [value]
varnish的命令行工具：
varnishadm,
varnishtop: 内存日志区域查看工具
RxHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.81 Safari/537.36
其中：
RxHeader：称为tag, 基于tag过滤，可使用-i或-x选项；
User-Agent起始的内容：称为日志信息，可使用-I或-X选项进行过滤；
-I regexp: 仅显示被模式匹配到的条目
-X regexp：仅显示不被模式匹配到的条目
-C: 忽略字符大小写；
-d: 显示已有日志；
varnishstat：
-f field, field, ...
-l: 列出所有可用字段
-x: xml输出格式
-j: json输出格式
varnishlog, varnishncsa
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