Varnish Proxy Cache

Varnish Proxy Cache

I. Basic varnish knowledge

How Varnish works

1. How varnish works

The client request arrives at the varnish proxy. The accept in the child thread receives the request process and submits it to the worker threads for processing. The worker threads first goes to the object expiry to find the cache, and then goes to the upstream server backend lcatinon to find the resource, return to the varnish proxy to check whether the cache rules are met. If yes, It is cached. If no, it is directly returned to the client.

2. cache Classification

Proxy Cache: the client requests the proxy and first looks for the cache. If the cache does not exist, the proxy finds the resource on the upstream server and caches it on the proxy, and then returns it to the client.

Bypass cache: the client goes to the cache to find the cache. If the cache does not hit the client, the client goes to the upstream server to find the resource and returns it to the local location. Then, the client caches the resource to the cache.

3. Applicable scenarios of Memcache

Disadvantages of memcache: it cannot adapt to real-time updates. If real-time updates occur, the cache does not hit the cache and the hit rate is low.

Apsaradb for memcache supports distributed caching. memcache is not required for mysql master-slave databases. memcache is suitable for multiple mysql cluster environments. In this case, the query performance can be better directly obtained from the mysql cache.

4. Functions of varnish status engines:

Vcl_recv: implements a security policy. It only processes http methods that can be identified and only caches get and head methods. It does not cache user-specific data (Cache policies based on client requests)

Vcl_fetch: cache policies based on server responses

Vcl_pipe: used to send requests directly to the backend host;

Vcl_hash: data source when custom hash is generated

Vcl_pass: used to pass requests directly to the backend host;

Vcl_hit: the operation to be performed when the cached object is found in the cache;

Vcl_miss: the operation to be performed to find the cached object from the cache;

Vcl_deliver: method used to respond the content of a user request to the client;

Vcl_error: Cache Policy for merging error responses on the varnish side;

5. Principle of Varnish Cache

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Structural notes for Varnish Cache

Install and configure Varnish-5.8 in CentOS 2.1.5

The RedHat script uses the CentOS source to update and install Nginx, PHP 5.3, and Varnish.

Using Varnish to build Cache Server notes

Install and configure the cache service Varnish

Preparations for Varnish compilation and Installation

Configuration Optimization of Varnish cache in Linux

Varnish Basic Concepts

Bytes -----------------------------------------------------------------------------------

Ii. varnish experiments

Node1 172.16.11.143 centos6.5 + varnish

Node2 172.16.11.144 centos6.5 + http

1. Software Installation

Http://repo.varnish-cache.org/redhat/varnish-3.0/el6/x86_64/varnish/

Varnish-libs-3.0.5-1.el6.x86_64.rpm

Varnish-3.0.5-1.el6.x86_64.rpm

Varnish-docs-3.0.5-1.el6.x86_64.rpm

Node1

Rpm-ivh varnish-libs-3.0.5-1.el6.x86_64.rpm varnish-3.0.5-1.el6.x86_64.rpm

/Etc/logrotate. d/varnish # Rolling logs

/Etc/rc. d/init. d/varnish # service

/Etc/rc. d/init. d/varnishlog # log

/Var/lib/varnish # shared Cache

/Var/log/varnish # log storage

/Etc/varnish/default. vcl # configuration file

2. Simple proxy configuration

Node1

VARNISH_LISTEN_PORT = 80

VARNISH_STORAGE_SIZE = 64 M # Set the cache size

#

# Backend storage specification

# VARNISH_STORAGE = "file, $ {VARNISH_STORAGE_FILE}, $ {VARNISH_STORAGE_SIZE }"

VARNISH_STORAGE = "malloc, $ {VARNISH_STORAGE_SIZE}" # What is the cache name?

Vim/etc/varnish/default. vcl

Backend default {

. Host = "172.16.11.144 ";

. Port = "80 ";

}

Service varnish restart

Ss-tnl # Check whether the port is listening

Node2

Yum install httpd-y

Vim/var/www/html/index.html

<H1> node2

Service httpd restart

Chkconfig -- add httpd

Chkconfig httpd on

3. Enable the backend server to view the client's access

Node1

Cp/etc/varnish/default. vcl/etc/varnish/test. vcl

Vim/etc/varnish/test. vcl

Sub vcl_recv {

If (req. restarts = 0 ){

If (req. http. x-forwarded-){

Set req. http. X-Forwarded-For =

Req. http. X-Forwarded-For + "," + client. ip;

} Else {

Set req. http. X-Forwarded-For = client. ip;

}

}

Return (lookup );

}

[Root @ localhost ~] # Varnishadm-S/etc/varnish/secret-t fig: 6082

Varnish> vcl. list # view available

200

Active 2 boot

Available 0 test1

Varnish> vcl. load test1 test1.vcl # compile

200

VCL compiled.

Varnish> vcl. use test1 # use

200

Varnish> vcl. list # view available

200

Available 2 boot

Active 0 test1

Node2

Vim/etc/httpd/conf/httpd. conf

LogFormat "% {X-Forwarded-For} I % l % u % t \" % r \ "%> s % B \" % {Referer} I \ "\" % {User-Agent} I \ "" combined

Service httpd reload

######################################## ######################################## #####

Test http: // 172.16.11.143 in a browser

Node2

Tail/var/log/httpd/access_log

172.16.0.101--[04/Sep/2014: 16: 43: 27 + 0800] "GET/favicon. ico HTTP/1.1 "404 288"-"" Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36"

4. Set to check whether the cache is hit

Node1

Vim/etc/varnish/test. vcl

Sub vcl_deliver {

If (obj. hits> 0 ){

Set resp. http. X-Cache = "Hit Via" + "" + server. hostname;

} Else {

Set resp. http. X-Cache = "Miss Via" + "" + server. hostname;

}

Return (deliver );

}

[Root @ localhost ~] # Varnishadm-S/etc/varnish/secret-t fig: 6082

Varnish> vcl. load test2 test1.vcl

200

VCL compiled.

Varnish> vcl. use test2

200

Varnish> vcl. list

200

Available 0 boot

Available 2 test1

Active 0 test2

Access F12 in a browser

5. Precisely set the page without caching

If (req. url ~"~ /Test.html $ "){

Return (pass)

}

Compile and use

Vcl. load test3 test1.vcl

Vcl. use test2

Vcl. list

Browser Test

Http: // 172.16.11.143/test/index.html

Variable usage rules

6. the built-in variables are used in that status engine.

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