How to assign Nginx upstream

1. Polling (default)

Each request is assigned to a different back-end server in chronological order, and can be automatically rejected if the backend server is down.

2, Weight
Specifies the polling probability, proportional to the weight and access ratios, for situations where the performance of the backend server is uneven.
For example:

Upstream Bakend {
server 192.168.159.10 weight=10;
Server 192.168.159.11 weight=10;
}

3, Ip_hash
Each request is allocated according to the hash result of the access IP, so that each visitor has fixed access to a back-end server that resolves the session issue.
For example:

Upstream resinserver{
Ip_hash;
Server 192.168.159.10:8080;
Server 192.168.159.11:8080;
}

4. Fair (third party)
The response time of the back-end server is allocated to the request, and the response time is short of priority allocation.

Upstream resinserver{
server server1;
Server Server2;
Fair;
}

5. Url_hash (Third Party)

Assign requests by the hash result of the access URL so that each URL is directed to the same back-end server, which is more efficient when the backend server is cached.

Example: Add a hash statement in upstream, the server statement can not write weight and other parameters, Hash_method is the use of the hash algorithm

Upstream resinserver{
server squid1:3128;
Server squid2:3128;
Hash $request _uri;
Hash_method crc32;
}
Tips:
upstream resinserver{#定义负载均衡设备的Ip及设备状态
Ip_hash;
Server 127.0.0.1:8000 down;
Server 127.0.0.1:8080 weight=2;
Server 127.0.0.1:6801;
Server 127.0.0.1:6802 backup;
}

In servers that need to use load balancing, add

Proxy_pass http://resinserver/;
The status of each device is set to:
1.down indicates that the server is temporarily not participating in the load
2.weight by default, the larger the 1.weight, the greater the load weight.
3.max_fails: The number of times that a request failed is allowed defaults to 1. Returns the error defined by the Proxy_next_upstream module when the maximum number of times is exceeded
4.fail_timeout:max_fails the time of the pause after the failure.
5.backup: When all other non-backup machines are down or busy, request the backup machine. So the pressure on this machine is the lightest.

Nginx supports multiple sets of load balancing at the same time, which is used for unused servers.

Client_body_in_file_only set to On can speak the client post data logged to the file to do debug
Client_body_temp_path setting a directory of record files can be set up to 3 levels of directories
The location matches the URL. Can redirect or perform new proxy load balancing