nginx Is a very good lightweight reverse proxy server , It can be done easily web And be able to load balance .

nginx adopt upstream To achieve load balancing, the specific configuration is as follows ：

upstream web_project {
    server 127.0.0.1:8080;
    server 127.0.0.1:8081;
}
server {
    location / {
        proxy_pass http://web_project;
    }
}

among web_project by upstream The name is arbitrarily named as the service name or project name ,nginx The default load balancing policy is polling

Other strategies include Weighted polling ：

upstream web_project {
    server 127.0.0.1:8080 weight=1;
    server 127.0.0.1:8081 weight=2;
}

among weight Said the weight , The greater the number , The heavier the load . The second service load in the example is the first one 2 times

In such as ：IP hash:

upstream web_project {
    ip_hash;
    server 127.0.0.1:8080;
    server 127.0.0.1:8081;
}

Same client IP It will be allocated to the same service, which can be used to solve the problem of distribution session Inconsistency .

In such as  fair:

upstream web_project {
server 127.0.0.1:8080;
server 127.0.0.1:8081;
fair;
}

Allocate according to the response time of the service , Priority allocation with short response time

In such as   url_hash：

upstream web_project {
server 127.0.0.1:8080;
server 127.0.0.1:8081;
hash $request_uri;
hash_method crc32;
}

URL hash and IP hash be similar , It's just that URL As hash Source , Availability guarantees that the same request will be assigned to the same service , among hash_method Indicates the hash Algorithm .

Finally, let's have a complete configuration

upstream web_project {
server 127.0.0.1:8080;
server 127.0.0.1:8081;
}
server {
listen 80;
server_name www.zux2.com;
root /home/webroot;
location / {
index index.html;
}
location ~.json$ { # Dynamic request （ All with .json The closing request ） Load balancing ,
proxy_pass http://web_project;
}
}

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