Nginx 代理 varnish 的姿勢
以前做網站的時候遇到了網站的訪問量很大，而導致后端處理程序響應超時而導致的一些問題。當時采用的架構是nginx+php-fastcgi，同事想到了用nginx-proxycache來做頁面緩存，效果也還行。下面我想介紹一下varnish的使用技巧
準備
varnish嚴格來說是可以當作一個代理服務器的軟件，直接將 HTTP 請求轉發到 php-cgi ,然后交給php處理,varnish會獲取經過php處理后的數據,最后返回給瀏覽器。如圖
但是，現在 php-fastcgi 已經被逐漸淘汰了，也就是說我們一般情況下不會使用 php-fastcgi ，那么我們不能直接將varnish與php組合，因為php-fpm的交互方式為socket，而不再是監聽本機的9000端口
所以我們必須找一個的媒介,連接 varnish 和 php-fpm , nginx 可以扮演這個媒介,如下圖：
那么問題來了，根據研究發現， varnish 處理 http 請求不如 nginx 那么高效。所以如果我們讓 nginx 做前鋒，這樣就更完美了。那我們需要怎么才能達到這個目的呢，下面我們來整理一下流程
下面就來實現一下圖三的架構吧。
事先需要準備 nginx , varnish , php-fpm , php 這些軟件，OS是 ubuntu ，所有軟件都可以用 apt-get install 來安裝，不了解包名全稱的話可以先 apt-get update ，更新一下源，然后再用 apt-cache search xxx 來查找軟件包名
安裝完 varnish 后，可以使用 service varnish 回車，查看可操作選項 * Usage: /etc/init.d/varnish {start|stop|restart|reload|force-reload|configtest} ,一般安裝完畢后，系統會自動啟動 varnish 的, nginx 也是一樣,便不贅述了
配置
安裝完所需的軟件后，下面需要配置這些軟件，來實現這個架構
nginx部分
vi /etc/nginx/nginx.conf
http {
## proxy global setting
proxy_connect_timeout 5;
proxy_read_timeout 60;
proxy_send_timeout 5;
proxy_buffer_size 16k;
proxy_buffers 4 64k;
proxy_busy_buffers_size 128k;
##END
## cache proxy pass
upstream cache {
server 127.0.0.1:6081;
}
##END
## php proxy pass
upstream php {
server 127.0.0.1:8080;
}
##END
# Basic Settings
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
server_tokens off;
#depend on nginx-extras 需要安裝nginx-extras才能定義Server
more_set_headers 'Server: Bird-shark';
# server_names_hash_bucket_size 64;
# server_name_in_redirect off;
include /etc/nginx/mime.types;
default_type application/octet-stream;
##
# SSL Settings
##
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
##
# Logging Settings
##
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
##
# Gzip Settings
##
gzip on;
gzip_disable "msie6";
gzip_vary on;
gzip_proxied any;
gzip_comp_level 6;
gzip_buffers 16 8k;
gzip_http_version 1.1;
gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;
##
# Virtual Host Configs
##
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}
vi /etc/nginx/sites-available/default
server {
listen 80 default_server;
listen [::]:80 default_server;
index index.html index.htm index.php;
server_name localhost;
location ~ .*\.(gif|jpg|png|css|js|flv|ico|swf|html)$ {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://cache;
}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
location / {
proxy_pass http://php;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass_header Server;
}
}
server {
listen 8080;
root /var/www/html;
index index.html index.htm index.php;
location / {
if (!-e $request_filename){
rewrite ^(.*)$ /index.php?s=$1 last;
break;
}
try_files $uri $uri/ =404;
}
location ~ ^(.+\.php)(.*)$ {
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_intercept_errors on;
fastcgi_buffers 8 128k;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
}
}
varnish部分
vi /etc/varnish/default.vcl
vcl 4.0;
# Default backend definition. Set this to point to your content server.
backend default {
.host = "127.0.0.1";
.port = "8080";
}
acl purgers {
"localhost";
#"103.22.188.169";
}
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.
if (req.restarts == 0) {
unset req.http.X-Purger;
}
if(req.method == "PURGE"){
if(!client.ip ~ purgers){
return(synth(405,"Not Allowed."));
}
return (purge);
#ban("obj.http.x-url ~ " + req.url);
}
if(req.method == "GET" && req.url ~ "\.(js|css|jpg|png|gif|swf|jpeg|ico)$"){
unset req.http.cookie;
}
}
sub vcl_backend_response {
#set beresp.http.x-url = bereq.url;
if (bereq.url ~ "\.(js|css|jpg|png|gif|swf|jpeg|ico)$") {
unset beresp.http.Cache-Control;
unset beresp.http.set-cookie;
set beresp.ttl = 10h;
set beresp.http.Cache-Control = "max-age=36000";
set beresp.do_gzip = true;
}
if(bereq.url ~ "\.html$"){
set beresp.ttl = 10m;
set beresp.do_gzip = true;
unset beresp.http.Cache-Control;
unset beresp.http.Pragma;
set beresp.http.Cache-Control = "max-age=600";
unset beresp.http.Expires;
}
}
sub vcl_deliver {
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT from " + req.http.host;
#set resp.http.X-Cache-Hits = obj.hits;
} else {
set resp.http.X-Cache = "MISS from " + req.http.host;
}
if (req.http.X-Purger) {
set resp.http.X-Purger = req.http.X-Purger;
}
unset resp.http.X-Powered-By;
unset resp.http.Server;
unset resp.http.Via;
unset resp.http.X-Varnish;
unset resp.http.Age;
#unset resp.http.x-url; # Optional
}
sub vcl_hit {
if (req.method == "PURGE") {
return (synth(200,"Purged."));
}
}
sub vcl_miss {
if (req.method == "PURGE") {
return (synth(404,"Purged."));
}
}
sub vcl_purge {
if (req.method == "PURGE") {
#set req.http.X-Purge = "Purged";
ban("req.url ~ "+req.url);
#return (restart);
set req.method = "GET";
set req.http.X-Purger = "Purged";
return (restart);
}
}
sub vcl_hash {
hash_data(req.url);
if (req.http.host) {
hash_data(req.http.host);
} else {
hash_data(server.ip);
}
if (req.http.cookie) {
hash_data(req.http.cookie);
}
if (req.http.Accept-Encoding ~ "gzip") {
hash_data("gzip");
} elseif (req.http.Accept-Encoding ~ "deflate") {
hash_data("deflate");
}
}
測試&分析
1. 在不使用緩存模塊的情況下
vi /etc/nginx/sites-available/default
#location ~ .*\.(gif|jpg|png|css|js|flv|ico|swf|html)$ {
# proxy_set_header Host $host;
# proxy_set_header X-Real-IP $remote_addr;
# proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
# proxy_pass http://cache;
#}
先用chrome瀏覽器訪問查看請求頭
我們再使用curl,在服務器上執行以下命令
curl -k -v 'http://192.168.99.1/Public/Home/images/t_navigation_logo.png' -H 'Pragma: no-cache' -H 'Accept-Encoding: gzip, deflate, sdch' -H 'Accept-Language: zh,en;q=0.8,zh-CN;q=0.6' -H 'Upgrade-Insecure-Requests: 1' -H 'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36' -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8' -H 'Connection: keep-alive' --compressed
發現有輸出內容。
然后，反選disable cache
然后在服務器上執行以下命令
curl -k -v 'http://192.168.99.1/Public/Home/images/t_navigation_logo.png' -H 'If-None-Match: "57c6b733-1962"' -H 'Accept-Encoding: gzip, deflate, sdch' -H 'Accept-Language: zh,en;q=0.8,zh-CN;q=0.6' -H 'Upgrade-Insecure-Requests: 1' -H 'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36' -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8' -H 'Connection: keep-alive' -H 'If-Modified-Since: Wed, 31 Aug 2016 10:53:39 GMT' --compressed
發現只返回了頭部信息，然而沒有內容返回
然后我們比較兩個命令 發現區別就在 -H 'Pragma: no-cache' 和 -H 'If-Modified-Since: Wed, 31 Aug 2016 10:53:39 GMT' -H 'If-None-Match: "57c6b733-1962"'
57c6b733-1962 這串字符對應的是服務器響應給瀏覽器的 ETag 部分的內容，然后我們修改一下部分的內容
curl -k -v 'http://192.168.99.1/Public/Home/images/t_navigation_logo.png' -H 'If-None-Match: "57c6b733-1234"' -H 'Accept-Encoding: gzip, deflate, sdch' -H 'Accept-Language: zh,en;q=0.8,zh-CN;q=0.6' -H 'Upgrade-Insecure-Requests: 1' -H 'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36' -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8' -H 'Connection: keep-alive' -H 'If-Modified-Since: Wed, 31 Aug 2016 10:53:39 GMT' --compressed
在服務器端執行一下。發現有內容返回，所以這個 ETag 相當于 token ，它不是由 nginx 隨便生成的，且跟請求鏈接應是一一對應的，用來標識緩存的,當服務器返回的狀態為 304 的時候,這時候我們瀏覽器會直接找到本地的緩存數據
2. 在使用緩存模塊的情況下
vi /etc/nginx/sites-available/default
location ~ .*\.(gif|jpg|png|css|js|flv|ico|swf|html)$ {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://cache;
}
用瀏覽器查看響應頭
發現 X-Cache:MISS from 192.168.99.1 .這表示緩存未命中，然后我們刷新 X-Cache:HIT from 192.168.99.1 ，這時候發現已經命中了。
對于已經命中的資源文件，我們如果將其刪除會出現什么效果呢，答案是，其依然可以訪問，除非重啟或者將緩存清除
但是對PURGE顯然是不對外公開的,以下是服務器端用curl清除varnish緩存的命令
curl -v -k -X PURGE http://localhost/Public/Home/css/t_navigation.css
結語
varnish 是一款內存類型的緩存軟件，而非nginx擴展proxy_cache那種物理緩存類型的軟件，存取速度比較快,但是也有弊端，重啟后所有緩存得重寫。不管怎么說，什么架子都適用的場景，要想滿足業務需求還是得搗鼓透徹，而我也只是將我想到的給實現出來，畢竟資源和精力都是有限的，也就隨便玩玩，諸位看客看看就好，別太認真，知道怎么回事兒就行。
來自：https://segmentfault.com/a/1190000006853425