利用varnish构建httpd缓存服务器

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varnish如何存储缓存对象：

    file: 单个文件；不支持持久机制；

    malloc: 缓存在内存中；

    persistent：基于文件的持久存储；（此方式不建议使用）

vcl：配置缓存系统的缓存机制；【线程中缓存功能的工作机制】
一、在vs2和vs3上安装http

写入文件，内容一个为on vs2，另一个为on vs3

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[iyunv@vs2 ~]# yum install http [iyunv@vs2 ~]# for i in {1..10}; do echo "web$i on vs2" > /var/www/html/test$i.html; done [iyunv@vs2 ~]# ls /var/www/html/ test10.html  test2.html  test4.html  test6.html  test8.html test1.html   test3.html  test5.html  test7.html  test9.html [iyunv@vs2 ~]# systemctl start httpd.service

二、安装varnish（在centos7上安装4.0.3版本）

1	[iyunv@vs1 ~]# yum install varnish

三、varnish主程序的配置文件

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[iyunv@vs1 ~]# vim /etc/varnish/varnish.params # Varnish environment configuration description. This was derived from # the old style sysconfig/defaults settings # Set this to 1 to make systemd reload try to switch vcl without restart. RELOAD_VCL=1 # Main configuration file. You probably want to change it. VARNISH_VCL_CONF=/etc/varnish/default.vcl    #读取vcl配置文件的位置 # Default address and port to bind to. Blank address means all IPv4 # and IPv6 interfaces, otherwise specify a host name, an IPv4 dotted # quad, or an IPv6 address in brackets. # VARNISH_LISTEN_ADDRESS=192.168.1.5 VARNISH_LISTEN_PORT=6081    #监听的服务端口为6081 # Admin interface listen address and port VARNISH_ADMIN_LISTEN_ADDRESS=127.0.0.1    #监听的管理地址为本机 VARNISH_ADMIN_LISTEN_PORT=6082    #监听的管理端口为6082 # Shared secret file for admin interface VARNISH_SECRET_FILE=/etc/varnish/secret    #密钥文件位置 # Backend storage specification, see Storage Types in the varnishd(5) # man page for details. VARNISH_STORAGE="file,/var/lib/varnish/varnish_storage.bin,1G"    #缓存以文件的方式的存储位置和大小 #VARNISH_STORAGE="malooc,256M"    #以内存方式缓存，缓存大小为256M # Default TTL used when the backend does not specify one VARNISH_TTL=120    #联系后端服务器超时时长 # User and group for the varnishd worker processes VARNISH_USER=varnish    #主进程所使用的用户 VARNISH_GROUP=varnish    #主进程所使用的组 # Other options, see the man page varnishd(1)    #进程选项，线程池的最大值最小值和超时时长 DAEMON_OPTS="-p thread_pool_min=5 -p thread_pool_max=500 -p thread_pool_timeout=300"

四、varnish的命令行管理工具

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[iyunv@vs1 ~]# varnishadm -S /etc/varnish/secret -T 127.0.0.1:6082 help       help [<command>]    #获取帮助信息 ping [<timestamp>]    #测试服务器是否正常 auth <response>    # quit                #退出 banner status            #显示服务器状态信息 start            #启动子进程 stop            #停止子进程 vcl.load <configname> <filename>    #载入哪个文件为配置文件 vcl.inline <configname> <quoted_VCLstring> vcl.use <configname>                #使用哪个vcl文件 vcl.discard <configname>            #删除哪个vcl文件 vcl.list                     #列出所有可用的vcl文件 param.show [-l] [<param>]            #显示运行时参数 param.set <param> <value>                panic.show                     #显示恐慌信息，显示进程或子进程上次挂掉的原因 panic.clear                                        #清除恐慌信息 storage.list                                        #显示缓存信息 vcl.show [-v] <configname>                        #显示vcl文件的详细信息，vcl编译前的样子 backend.list [<backend_expression>]                #显示后端服务器列表 backend.set_health <backend_expression> <state>    #手动上线下线后端服务器 ban <field> <operator> <arg> [&& <field> <oper> <arg>]...    #清理缓存中的缓存对象 ban.list                                             #显示定义的清理缓存规则

varnish的访问日志

1 2	[iyunv@vs1 ~]# varnishlog [iyunv@vs1 ~]# varnishtop

varnish的统计信息

1	[iyunv@vs1 ~]# varnishstat

五、vcl配置文件的说明

http://book.varnish-software.com/4.0/chapters/VCL_Basics.html

http://book.varnish-software.com/4.0/_images/simplified_fsm.svg

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vcl_recv    接收请求 cacheable    判断是否为可缓存对象 incache        判断hash后的结果是否存在 vcl_hash    可缓存对象hash计算 vcl_hit    缓存中命中 vcl_miss    缓存中未命中 vcl_fetch    获取后端内容 vcl_deliver    构建缓存发送 vcl_pipe        客户端请求的方法不是常见方法时，直接交给后端服务器处理 vcl_pass        不检查缓存直接从后端服务器取 vcl_error    varnish直接返回错误响应

六、vcl配置文件

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[iyunv@vs1 ~]# cp /etc/varnish/default.vcl /etc/varnish/test.vcl [iyunv@vs1 ~]# vim /etc/varnish/test.vcl # 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; # Default backend definition. Set this to point to your content server. backend vs2 {    #定义后端主机vs2     .host = "172.16.24.102";     .port = "80";     .probe = {    #对后端主机的test1进行进行健康状态检测         .url = "/test1.html";         } } backend vs3 {     .host = "172.16.24.104";     .port = "80";     .probe = {         .url = "/test1.html";         } } #import directors;    #加载directors模块，在负载均衡轮询时要用到 #sub vcl_init {        #轮询方式的负载均衡 #    new mycluster = directors.round_robin(); #    mycluster.add_backend(vs2); #    mycluster.add_backend(vs3); #} sub vcl_recv {     # Happens before we check if we have this in cache already.     #     # Typically you clean up the request here, removing cookies you don't need,     # rewriting the request, etc.           #url中开头带有login或者admin的直接从后端主机取结果不缓存     if (req.url ~ "(?i)^/login" || req.url ~ "(?i)^/admin") {           return(pass);     }     #url以jpg,png,gif结尾的直接发给vs2，其他的都发给vs3     if (req.url ~ "(?i)\.(jpg|png|gif)$") {         set req.backend_hint = vs2;     } else {         set req.backend_hint = vs3;     } #    set req.backend_hint = mycluster.backend();    #负载均衡集群 #如果客户端请求为PRI返回405，如果请求的为非GET,HEAD,PUT,POST,TRACE,OPTIONS,DELETE都直接发给后端主机处理     if (req.method == "PRI") {         /* We do not support SPDY or HTTP/2.0 */         return (synth(405));     }     if (req.method != "GET" &&       req.method != "HEAD" &&       req.method != "PUT" &&       req.method != "POST" &&       req.method != "TRACE" &&       req.method != "OPTIONS" &&       req.method != "DELETE") {         /* Non-RFC2616 or CONNECT which is weird. */         return (pipe);     }     if (req.method != "GET" && req.method != "HEAD") {         /* We only deal with GET and HEAD by default */         return (pass);     }     if (req.http.Authorization || req.http.Cookie) {         /* Not cacheable by default */         return (pass);     }     return (hash); } sub vcl_backend_response {     # Happens after we have read the response headers from the backend.     #     # Here you clean the response headers, removing silly Set-Cookie headers     # and other mistakes your backend does. } sub vcl_deliver {     # Happens when we have all the pieces we need, and are about to send the     # response to the client.     #     # You can do accounting or modifying the final object here.     #如果缓存能命中就在返回值中插入HIT,未命中则插入MISS     if (obj.hits>0) {         set resp.http.X-Cache = "HIT";     } else {         set resp.http.X-Cache = "MISS";     } } [iyunv@vs1 ~]# varnishadm -S /etc/varnish/secret -T 127.0.0.1:6082 vcl.load test2 test.vcl 200         VCL compiled. vcl.use test2 200         VCL 'test2' now active

七、测试

在vs2上上传一张dog.jpg，在vs3上不上传任何图片