varnish

安装：

yum install epel-release
rpm --nosignature -i https://repo.varnish-cache.org/redhat/varnish-4.0.el6.rpm
yum install varnish gcc varnish-libs-devel-4.0.3 -y

稍微配置：

vi /etc/sysconfig/varnish　　修改listen port为80

vi /etc/varnish/default.vcl　　添加backend web server

web缓存核心技术：

http://mp.weixin.qq.com/s?__biz=MzIyMDA1MzgyNw==&mid=2651968866&idx=1&sn=25554c31eac32e78664b962412f515de&chksm=8c349d4ebb431458bef22609db7e9e76d33035ad92c31cbb2d201d13ce94bb8203c69ab9fb33&scene=21#wechat_redirect

引用自：　　http://467754239.blog.51cto.com/4878013/1577216

# Configure VCL
 
probe static_chk {    #静态网页的健康状态检查
        .url = "/test.html";
        .interval = 2s;
        .timeout = 2s;
        .expected_response = 200;
}
probe dynamic_chk {    #动态网页的健康状态检查
        .url = "/test.php";
        .interval = 2s;
        .timeout = 2s;
        .expected_response = 200;
}
backend apache01 {    #静态请求负载均衡1
        .host = "192.168.0.108";
        .port = "80";
                .probe = static_chk;
}
backend apache02 {    #静态请求负载均衡2
        .host = "192.168.0.110";
        .port = "80";
                .probe = static_chk;
}
backend nginx01 {    #动态请求分发地址
        .host = "192.168.0.100";
        .port = "80";
                .probe = dynamic_chk;
}
 
director myload random {    #分发器和调度算法
        .retries = 2;
        {
                .backend = apache01;
                .weight = 1;
        }
        {
                .backend = apache02;
                .weight = 1;
        }
}
sub vcl_recv {
        set req.http.X-Forward-For = client.ip;    #记录客户端的ip地址
        if (req.url ~ ".(html)$" ) {
                return(lookup);
        }
        if (req.url ~ ".(php)$") {  #如果请求的是php文件则将请求发送给nginx代理的服务器
                set req.backend = nginx01;
        }else{
                set req.backend = myload; #如果请求的是html文件则将请求发送给myload代理的服务器
        }
}
sub vcl_fetch {
        if (req.request == "GET" && req.url ~ ".(html|jpg|jpeg)$") {
                set beresp.ttl = 3600s;
        }
}
 
sub vcl_deliver {            #记录命中和未命中的变量设定
        if (obj.hits > 0) {
                set resp.http.X-Cache = "HIT from" + " " + server.ip;
        } else {
                set resp.http.X-Cache = "MISS";
        }
        return(deliver);
}

引用自：　　http://www.cnblogs.com/xiaocen/p/3715266.html

#
# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and http://varnish-cache.org/trac/wiki/VCLExamples for more examples.
# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;
import directors;
probe backend_healthcheck { # 创建健康监测
    .url = /health.html;
    .window = 5;
    .threshold = 2;
    .interval = 3s;
}
backend web1 {    # 创建后端主机
    .host = "static1.lnmmp.com";
    .port = "80";
    .probe = backend_healthcheck;
}
backend web2 {
    .host = "static2.lnmmp.com";
    .port = "80";
    .probe = backend_healthcheck;
}
backend img1 {
    .host = "img1.lnmmp.com";
    .port = "80";
    .probe = backend_healthcheck;
}
backend img2 {
    .host = "img2.lnmmp.com";
    .port = "80";
    .probe = backend_healthcheck;
}
vcl_init {    # 创建后端主机组，即directors
    new web_cluster = directors.random();
    web_cluster.add_backend(web1);
    web_cluster.add_backend(web2);
    new img_cluster = directors.random();
    img_cluster.add_backend(img1);
    img_cluster.add_backend(img2);
}
acl purgers {    # 定义可访问来源IP
        "127.0.0.1";
        "192.168.0.0"/24;
}
sub vcl_recv {
    if (req.request == "GET" && req.http.cookie) {    # 带cookie首部的GET请求也缓存
        return(hash);
}
    if (req.url ~ "test.html") {    # test.html文件禁止缓存
        return(pass);
    }
    if (req.request == "PURGE") {    # PURGE请求的处理
        if (!client.ip ~ purgers) {
            return(synth(405,"Method not allowed"));
        }
        return(hash);
    }
    if (req.http.X-Forward-For) {    # 为发往后端主机的请求添加X-Forward-For首部
        set req.http.X-Forward-For = req.http.X-Forward-For + "," + client.ip;
    } else {
        set req.http.X-Forward-For = client.ip;
    }
    if (req.http.host ~ "(?i)^(www.)?lnmmp.com$") {    # 根据不同的访问域名，分发至不同的后端主机组
        set req.http.host = "www.lnmmp.com";
        set req.backend_hint = web_cluster.backend();
      } elsif (req.http.host ~ "(?i)^images.lnmmp.com$") {
            set req.backend_hint = img_cluster.backend();
      }
        return(hash);
    }
sub vcl_hit { # PURGE请求的处理
    if (req.request == "PURGE") {  
        purge;
        return(synth(200,"Purged"));
    }
}
sub vcl_miss {    # PURGE请求的处理
    if (req.request == "PURGE") {
        purge;
        return(synth(404,"Not in cache"));
    }
}
sub vcl_pass {    # PURGE请求的处理
    if (req.request == "PURGE") {
        return(synth(502,"PURGE on a passed object"));
    }
}
sub vcl_backend_response { # 自定义缓存文件的缓存时长，即TTL值
    if (req.url ~ ".(jpg|jpeg|gif|png)$") {
        set beresp.ttl = 7200s;
    }
    if (req.url ~ ".(html|css|js)$") {
        set beresp.ttl = 1200s;
    }
    if (beresp.http.Set-Cookie) { # 定义带Set-Cookie首部的后端响应不缓存，直接返回给客户端
        return(deliver);
    }
}
sub vcl_deliver {
    if (obj.hits > 0) {    # 为响应添加X-Cache首部，显示缓存是否命中
        set resp.http.X-Cache = "HIT from " + server.ip;
    } else {
        set resp.http.X-Cache = "MISS";
    }
}

http://xiaodong88.blog.51cto.com/1492564/1304988/　　varnish

https://www.varnish-cache.org/docs/4.0/whats-new/upgrading.html#directors-have-been-moved-to-the-vmod-directors　　　　4.0改动

4.0改动后新的负载均衡配置：

vcl 4.0;
import directors;
backend apache1 {
    .host = "10.188.12.201";
    .port = "80";
}
backend apache2 {
    .host = "10.188.12.203";
    .port = "80";
}

sub vcl_init {
        new cluster1 = directors.round_robin();
        cluster1.add_backend(apache1);
        cluster1.add_backend(apache2);
}

sub vcl_recv {
set req.backend_hint = cluster1.backend();
}